TKO Upgrade

[eschaider]

Originally Posted by MaSnaka

Thanks for all the info guys. Eshader you are the only one I have heard with a complaint about the Tremec TKO600. Very discouraging to hear. Does any one else have trouble with shifting and worse 3rd gear getting chewed up? Not sure I'm interested in a 6th gear though. ...


Thanks,
John

If you will be driving the car in a less than 'spirited' and/or non -competitive manner the TKO600 is a fine transmission. If you drive it in a competitive fashion and attempt to rapidly change gears from second to third it will not cooperate the way it is delivered from Tremec.

Some guys call it notchy some guys call it other names but rapidly changing gears from second to third is a problem in the transmission as delivered by Tremec since time immemorial. Attempts at doing it more often than not end up in a missed shift from second to third.

The problem is the interlock timing that Tremec built into the shift detents on the internal shift rods to prevent engaging two gears at the same time. They erred on their design in a fashion that precludes rapid gear changes. Changing shifters, synchronizers, trans fluid, shucks even the air pressure in your right from tire has no effect on the underlying design miscue. On the oither hand, Tremec does have replacement shifter rods that will correct the interlock timing whoops and importantly also the second to third shift quality.

The third gear alignment problem is present in all TKO600's according to Tremec engineering. The issue (reportedly) had to do with their transition from a two piece countershaft on the TKO500, that was prone to shear it's woodruff key under load, to the newer design TKO600 one piece countershaft. Now instead of shearing a countershaft key we can shear teeth off of two gears at exactly the same time!

To provide clearance for the machining chips the gear hob creates as the countershaft third gear is hobbed, Tremec needed to leave a gap for the chips to escape. That gap (between the countershaft second and third gears) is the origin of the 3rd gear countershaft misalignment with the mainshaft third gear. When they changed the gear placement on the countershaft they did not do the same for the main shaft.

As long as you do not hook up your tires in third gear under full power and/or do not have a relatively robust engine you are not likely to have a problem. On the other hand if you nave a relatively robust engine and you also hook up in third you are in a dance with the devil. It is unlikely (but not impossible) to break it on the first attempt however repeated WOT third gear operation with the tires hooked will kill it.

Part of the good news is that WOT in third gear is a relatively inspiring phenomena in one of these cars and most people (unless they are racing) don't do that very often, if at all. If you do then the game of Russian Transmission Roulette is alive, well and on.

When I had my TKO600 modified by Liberty I believe the cost of all the parts was about $400. I don't remember if there was also a labor charge or if it was included. Either way, price wise your TKO very quickly looks like a T-56 Magnum — pricewise. A telephone call to Liberty can quickly get you the current pricing. Don't forget to add freight up and back unless you intend to do the mods yourself. And of douse don't forget this only corsets the shifting problems. You still have the nicely misaligned third gear problem.

As the Liberty rep at the time suggested to me I would have been better off to use the T56 if I were starting fresh w/o any parts bought yet.

Here are the dimensions from Tremec for a TKO;



Here are the dimensions from Tremec for a T-56 Magnum;



While not exactly the same they are close enough either transmission can easily be made to fit.

It simply comes down to builder preferences and what is important to you — as do most choices in these cars.


Ed

[blykins]

I would refrain from using absolutes...

I have numerous 600's in road race, drag race, and super hot street stuff and have never had a customer break a gear. This is up to 600-650 hp, launching on wrinkle walls and shifting at 7000.

[eschaider]

Originally Posted by blykins

I would refrain from using absolutes...

I have numerous 600's in road race, drag race, and super hot street stuff and have never had a customer break a gear. This is up to 600-650 hp, launching on wrinkle walls and shifting at 7000.

I understand what you are saying Brent and while the third gear breakage was (to my knowledge) not experienced at launch in first or third gear it was experienced in a gear change from second to third, in a drag car, with a medium power level (but torquey) big block, in a heavier car than a Cobra.

The Tremec designed third gear misalignment in their TKO600 transmissions unnecessarily loads the engaged third gear, gear teeth higher than they would otherwise be loaded with a full face contact design. Whenever you do that to a driving and driven set of gears they will fail sooner than the same gears with full face contact — it's just the mechanics of the gear system. This is a similar phenomena to getting the pinion depth wrong on a ring and pinion. Will they fail right away? Probably not. Will they fail sooner than a properly set up ring and pinion, yup.

While it is not an absolute that you will get shot every time you play Russian Roulette, it is true that the more often you play the more likely you are to get shot, again sort of a similar phenomena here. I think the number of Cobra's who can load their third gear, gears to their breaking threshold is relatively small, more because of the car weight and the spectacular experience available in car at WOT in third gear. That however does not mean that they will not fail. Importantly if and when they do fail the attendant gear tooth shrapnel is capable of expanding the scope of the failure if it gets into other gear sets inside the transmission.

So where is that magic line in the sand you don't want to cross? I can't say with any certainty. We do know Tremec claims the transmission is rated at 600 ft/lbs. They don't say if that is true for all gears some gears or only one set of gears. They also, to my knowledge, don't say if that is a sustained torque loading or a shock loading like we might see launching the car in a drag race style fashion. My suspicion (and that's all it is — a suspicion) is it is a continuous duty loading for a single gear set probably first gear.

If that is true (and that's a big if) it means 600 ft/lbs of torque and more represent a potential component failure threshold in third gear, again if everything is hooked up and really transmitting that much torque. How often can you do it with the misaligned gears? I don't believe there is any test data to give insight to that elusive number. However, we do know it happens and we do know those gears are misaligned 0.140" (if you believe Tremec).

Does this mean we should all forsake our TKO600's, probably not. Is it appropriate to make the knowledge available to someone who is contemplating the purchase of a new Tremec transmission? I think so. I know I would have liked to have had the knowledge before spending my monies and I think others might also. Will it or should it change everyone's mind? I doubt it and I don't think so but it will make some reconsider what they are about to buy and potentially allow them to make a better decision — for themselves.

In the final analysis if you are going to spend $2,400+ on a transmission why not buy the most robust unit with the highest torque rating and the best shifting qualities that will fit into your car for the dollars that you are about to spend?


Ed

[blykins]

Ed,

I appreciate all your input that you provide on Club Cobra and I usually take time to read your posts and digest your information.

However, in this one instance, I'm going to have to strongly disagree with the information you have provided.

Just in case I was out in left field, I emailed my Tremec supplier, since he is a dealer and is a Tremec-authorized repair facility, and asked him how many instances he has seen where the 3rd gear has eaten itself away or the cluster shaft gear has been eaten away because of misalignment.

His reply is that it's a new one to him, and if that were the case, he would be seeing a lot of irregular gear patterns, 3rd gear bearing cage damage, or just warranty repairs in general to fix the issue.

As I mentioned before, I've never heard of this, and I sell quite a few TKO's, as well as put them behind a lot of hipo engines that I provide. Some of them go behind road race engines, some go behind drag race engines, and some go behind 650-700 hp street engines.

Now, with that being said, the TKO's don't have a reputation of being the best shifters, especially at higher rpms. This gets better as the trans wears in, but we often do upgrades to correct gear cone and synchronizer hub surface finish, as well as upgrading the shift finger, blocking rings, etc. That usually takes care of the shifting issue, all the way up to 7500 rpm.

The TKO 600 is rated for 600 lb-ft of continuous torque on a trans dyno. If I'm not mistaken, this is rated in all gears except for overdrive. I can recheck this.

The Magnum T-56 is not (IMO) the solution to everyone's needs. In addition to the extra requirements to fit them behind some engine combinations, they are much more expensive, about 4" longer in length past the bellhousing, and much bigger around. This proves to be a big issue in some transmission tunnels, and in the case of a Cobra replica, with an already short driveshaft, shaving another 4" off the body length doesn't leave much.

The one failure from 8 years ago, that you have talked about and showed pictures of, seems to have been an isolated case. I just don't agree with making a blanket statement that says that all TKO's are timebombs, or that each prospective buyer needs to sit down and let this weigh heavily on their mind.

In my own mind, it's a non-issue.

[joyridin']

I put a T56 in my car. It is a HUGE transmission in physical size and it is heavy. Looking back, I would have been much better off with a TKO 600. I got the T56 at such a good deal, it was hard to pass up at the time.

The only time I use 6th is on the highway cruising at 70 MPH or above. You cannot use it for anything less than that. The RPM's even with 3.70 gears are just too low unless you have EFI and other additions to make your car drivable at very low RPM's. I use 5th gear most of the time at 70 MPH or less on the highway.

[bobcowan]

Originally Posted by blykins

Ed,

The one failure from 8 years ago, that you have talked about and showed pictures of, seems to have been an isolated case. I just don't agree with making a blanket statement that says that all TKO's are timebombs, or that each prospective buyer needs to sit down and let this weigh heavily on their mind.

In my own mind, it's a non-issue.

Maybe I'v been lucky, and I can only comment on one TKO (mine). I'v been beating the stuffings out of my trans for nearly a decade. High rpm shifts can sometimes be difficult. And it is just a little bit notchy; overall I like the feel. But it's holding up well (knock on wood).

[eschaider]

Originally Posted by blykins

Ed,

I appreciate all your input that you provide on Club Cobra and I usually take time to read your posts and digest your information.

However, in this one instance, I'm going to have to strongly disagree with the information you have provided.

...

The one failure from 8 years ago, that you have talked about and showed pictures of, seems to have been an isolated case. I just don't agree with making a blanket statement that says that all TKO's are timebombs, or that each prospective buyer needs to sit down and let this weigh heavily on their mind.

In my own mind, it's a non-issue.

I think we are actually closer together in our positions than you might suspect Brent.

My summary comments about the transmission were:

Originally Posted by eschaider

If that is true (and that's a big if) it means 600 ft/lbs of torque and more represent a potential component failure threshold in third gear, again if everything is hooked up and really transmitting that much torque. How often can you do it with the misaligned gears? I don't believe there is any test data to give insight to that elusive number. However, we do know it happens and we do know those gears are misaligned 0.140" (if you believe Tremec).

I went on to say;

Originally Posted by eschaider

Does this mean we should all forsake our TKO600's, probably not. Is it appropriate to make the knowledge available to someone who is contemplating the purchase of a new Tremec transmission? I think so. I know I would have liked to have had the knowledge before spending my monies and I think others might also. Will it or should it change everyone's mind? I doubt it and I don't think so but it will make some reconsider what they are about to buy and potentially allow them to make a better decision — for themselves.

I suspect what may have wrankled your (and possibly others) sensibilities was the clarity of the failure description and the publication of the Tremec design miscue in terms of gear tooth face alignment. I can well appreciate how the sudden awareness of a design flaw of that type in anyone's transmission can cause anxieties that did not previously exist — after all I own one also. It is however, none the less important and our obligation to be as informed and knowledgeable as reasonably possible so we can best decide for ourselves. I believe I also spoke to that in my closing paragraph where I said;

Originally Posted by eschaider

Does this mean we should all forsake our TKO600's, probably not. Is it appropriate to make the knowledge available to someone who is contemplating the purchase of a new Tremec transmission? I think so. I know I would have liked to have had the knowledge before spending my monies and I think others might also. Will it or should it change everyone's mind? I doubt it and I don't think so but it will make some reconsider what they are about to buy and potentially allow them to make a better decision — for themselves.

I think it is better for a potential purchaser of these types of components to have as much information as possible, both good and bad, prior to making a purchase decision about these or for that matter any other high value component in the car. When we use that information in our own decision/selection processes we will not all come up with the same choices but, we will come up with choices we think are best — for our own builds. Which when you think about it, is what the world's largest non-biased cobra site is supposed to be about and among other things foster? [Although in as much as we all own Cobra's we might have just a smidgen of bias ...)

In fact in my closing few sentences I suggest;

Originally Posted by eschaider

In the final analysis if you are going to spend $2,400+ on a transmission why not buy the most robust unit with the highest torque rating and the best shifting qualities that will fit into your car for the dollars that you are about to spend?

I chose to ambiguously identify that transmission because it could have been a variety of the Tremec offerings, a Richmond, a Top Loader, a G-Force or one of a number of other transmission alternatives. It is after all what the builder determined to be best for his purposes and his build given the information available to him at the time of selection/purchase.

In the end I don't think we are actually all that far apart. BTW I genuinely do enjoy and appreciate your perspective, input and insightful commentary on the site here.


Ed

[blykins]

I mainly had trouble with these statements:

"As long as you do not hook up your tires in third gear under full power and/or do not have a relatively robust engine you are not likely to have a problem. On the other hand if you nave a relatively robust engine and you also hook up in third you are in a dance with the devil. It is unlikely (but not impossible) to break it on the first attempt however repeated WOT third gear operation with the tires hooked will kill it."

"This is a royal PITA when everything goes right. When things go bump in the dark it'll blow you mind and your patience. This is something Tremec has known about for a decade (maybe more) and chosen to do absolutely nothing about!"

"While it is not an absolute that you will get shot every time you play Russian Roulette, it is true that the more often you play the more likely you are to get shot, again sort of a similar phenomena here. I think the number of Cobra's who can load their third gear, gears to their breaking threshold is relatively small, more because of the car weight and the spectacular experience available in car at WOT in third gear. That however does not mean that they will not fail. Importantly if and when they do fail the attendant gear tooth shrapnel is capable of expanding the scope of the failure if it gets into other gear sets inside the transmission."

Those statements infer that:

1. Any car with a TKO 600, a handful of horsepower, and good traction will most likely shatter 3rd gear.

Of course that's not true. I forgot to mention the '69 Mustang that belongs to a customer of mine with a 529 inch Boss headed big block...740 hp and 700 lb-ft of torque. No issues.

2. There are instances throughout the world of TKO 600's breaking 3rd gears and clustershafts because of a 'known' manufacturing defects and they choose to simply not do anything about it.

Of course that's not true either. If I were a multi-million dollar company making 1000's of transmissions at a time, I most likely wouldn't do a re-design, tooling change, etc., for just ONE instance of a failure.

3. Using a TKO 600 is just like rolling the dice everyday...

There were many insinuations in your posts Ed that were based on ONE known failure and, honestly, just a lot of your own opinions.

Thousands upon thousands of people read these posts and there's just no reason for misinformation to be passed around.

[eschaider]

Originally Posted by blykins

I mainly had trouble with these statements:

"As long as you do not hook up your tires in third gear under full power and/or do not have a relatively robust engine you are not likely to have a problem. On the other hand if you nave a relatively robust engine and you also hook up in third you are in a dance with the devil. It is unlikely (but not impossible) to break it on the first attempt however repeated WOT third gear operation with the tires hooked will kill it."

You are correct Brent, I think the absolute in my last sentence could have / should have been picked more artfully and carefully. To state, 'you will kill it', is not fair nor appropriate. There are any number of cars who will not possess sufficient torque, traction or weight to damage the transmission. What we do know is there are those that do, can and have. It is not speculation it is a matter of fact. What we don't know is how many, what types or how frequently.

Originally Posted by blykins

"This is a royal PITA when everything goes right. When things go bump in the dark it'll blow you mind and your patience. This is something Tremec has known about for a decade (maybe more) and chosen to do absolutely nothing about!"

This is simply a statement of fact. Unless you have taken the time and effort to shorten and modify one of the TKO600 mainshaft third gears to accept the replaceable synchronizer teeth like the high gear input shaft uses, you simply have no frame of reference with which to judge the process against. After the shortening and machining to look like the input shaft's replaceable synchronizer register, the job is not complete until a corresponding spacer is sized, machined and fit between second gear and third gear to properly position third with its driven countershaft equivalent, correcting the tooth face misalignment.

When I contacted Tremec engineering about this problem in late 2006 (if I recall correctly) to make them aware of it, they told me they knew when they designed the transmission that there was a misalignment and it amounted to ~0.140" (according to Tremec's doc at the time) moreover it was necessary in order to manufacture the one piece TKO600 countershaft. When I suggested the third gear fix to the problem the engineer informed me the transmission had never failed in service — a rather amazing service record for any mechanical device! When I sent him a pic of the destroyed gears he indicated the T-56 was the company's focus going forward and the TKO was what it was.

While you were not party to that conversation, I was. It represented a callous lack of regard for a known (to Tremec) problem and depending on application a discoverable problem for the end user of the transmission. It also said the company was focusing on other products going forward and not putting any further maintenance or development efforts into this particular transmission or problem.

That is all right and that is also the company's right and privilege. It is also something the purchaser/end user ought to at least be aware of in his selection process.

Originally Posted by blykins

"While it is not an absolute that you will get shot every time you play Russian Roulette, it is true that the more often you play the more likely you are to get shot, again sort of a similar phenomena here. I think the number of Cobra's who can load their third gear, gears to their breaking threshold is relatively small, more because of the car weight and the spectacular experience available in car at WOT in third gear. That however does not mean that they will not fail. Importantly if and when they do fail the attendant gear tooth shrapnel is capable of expanding the scope of the failure if it gets into other gear sets inside the transmission."

Those statements infer that:

1. Any car with a TKO 600, a handful of horsepower, and good traction will most likely shatter 3rd gear.

Of course that's not true. I forgot to mention the '69 Mustang that belongs to a customer of mine with a 529 inch Boss headed big block...740 hp and 700 lb-ft of torque. No issues.

The inference you have drawn is in fact your own and not mine, nor my words. My respective words are in blue above. While you are absolutely entitled to your own interpretation and inferences it is noteworthy it is your interpretation, your words and your inferences not mine nor what I said.

Originally Posted by blykins

2. There are instances throughout the world of TKO 600's breaking 3rd gears and clustershafts because of a 'known' manufacturing defects and they choose to simply not do anything about it.

Of course that's not true either. If I were a multi-million dollar company making 1000's of transmissions at a time, I most likely wouldn't do a re-design, tooling change, etc., for just ONE instance of a failure.

Those are not my words Brent. Those are your words. My words from post #8 above were:

This is a royal PITA when everything goes right. When things go bump in the dark it'll blow you mind and your patience. This is something Tremec has known about for a decade (maybe more) and chosen to do absolutely nothing about!

The PITA comment was a direct reference to the remanufacturing effort associated with modifying the mainshaft third gear. The immediately following sentence which you can see in blue above is quite different than what you have asserted I have said, when in fact I did not.

Originally Posted by blykins

3. Using a TKO 600 is just like rolling the dice everyday...

There were many insinuations in your posts Ed that were based on ONE known failure and, honestly, just a lot of your own opinions.

You may choose (for whatever reason) to season the wording to fit your own purposes and that is alright — for your purposes. For my part I attempted to stay as factual as possible. The words in your point #3 above are again your words not mine.

Once again and concisely in one spot, the facts are as follows;

It is a fact that,

◉ Third gear has a 0.140" countershaft/mainshaft mismatch according to Tremec,

◉ Tremec has known of this mismatch since the design phase of the TKO600,

◉ Tremec intends to do nothing about the mismatch,

◉ Tremec stated the transmission has never failed in service, (in fairness they probably meant third gear),

◉ Despite their representations to the contrary, third gear has failed in service at least one time we are all aware of,

◉ We do not have an adequately broad enough view of the total TKO600 product sales to know how many more have failed and Tremec will not assist,

◉ We do know one has failed,

◉ We do know anything that has failed once can fail again,

◉ We are not privy to the threshold conditions necessary to fail the transmission,

◉ It is to our advantage to know about this type of failure when selecting a transmission so we can select in our own best interests.

I think the bulleted facts above can easily stand on their own. I don't believe I have intentionally included my opinions but rather stayed very close to known fact. If you have an example of my use of an opinion as fact I will certainly restate the bullet to reflect fact and remove or retract the opinion.

Originally Posted by blykins

Thousands upon thousands of people read these posts and there's just no reason for misinformation to be passed around.

I could not agree more with you on that point Brent. That is why it is important for potential transmission shoppers to know about this kind of 'stuff'. Maybe it will be a non issue for their build but on the other hand maybe it will not.

If it falls into the maybe it will not category, or close enough they don't want to take a chance, then we are doing for someone else what I would think most of us would hope someone would do for us if roles were reversed. That's a fairly honorable endeavor no matter how you look at it.


Ed

[blykins]

Thanks for your words, Ed.

I can only say that I wish every mechanical component that I come into contact with only had one instance of failure in over 8 years, across THOUSANDS of samples. That is an excellent record, and to be honest, if I were Tremec, I wouldn't address it either.

Considering the amount of people that frequent this site, I've yet to see anyone else who has ever mentioned anything else about this particular problem. Further more, my distributor who has seen hundreds and hundreds of these transmissions, had never heard of this problem before.

I would consider that a stellar product and it only further causes me to endorse it in the future.

I only wish to deal with parts that have high reputations. There are crankshafts that I will use and not use. There are rods that I will use and not use. There are even clutches that I will or will not use. In my years of selling clutches, I have only had one McLeod issue and no RAM clutch issues (aside from installation errors, etc.) that I can remember. It seems like the TKO has proven itself along side of those products.

[Lightingrod]

I have been trying to get around to swapping to a TKO-600 for over a year now! I now have a built GM 700R-4 in it now. I'm not happy with the converter, @ 3000 rpm stall I may have went a bit high for the cam I have. One would think that at 62 years old I would know myself a bit better? Mild cam and carb will be enough, NOT!

I have the CRII peddle setup and a Monza V8 bellhousing. I'm planning to go with a light weight flywheel and a good single disc clutch. I'm going to pull engine and trans out and do a cam and intake swap while I'm at it! I'm going up from the Comp 280 AR (.550" lift, 280*) to the 300 AR (.575" lift, 300*) and from an RPM Air Gap to a Victor single plan intake! This is on a SBC 388, 10-1 CR with AFR 210 Race Ready Heads (2.08" x 1.60" valves), it also has a Rev Kit on it. It should pull strong to 6700-7000 but the torque is going to take a pretty big hit below 3500. SOoooo I'm going to also put a (50-75 hp) NOS TopShot on it. This should keep even my old foolish azz happy at least for a while?

I have an drum brake 8.8" with 4.11 gears and a disc brake 8.8" with I don't know what! My plan is to leave the 4.11rearend in and see what's up with the RR TKO .82 5th. If 4.11 is to much I'll go with 3.73-3.55 when I install the disc brake rear.

If anyone is running a TKO, what shifter position are you using?

This will get DONE this winter!

:-)

[Silversmith]

Very good post, thanks to all.

[RET_COP]

I've been on the Ford websites a lot over the years and those guys Hamer the crap out of those transmissions, faceplated and all and i never heard of breaking third gear. Ive seen a lot of carnage in my years of drag racing, could this isolated incident just be a bad third gear from a metallurgy standpoint. I mean this stuff happens. I don't doubt that the .140 is an issue but does it directly result in a breakage problem the we all know about? Im not seeing that.

[RET_COP]

Tko 600RR steeda tri ax with a nice steeda shifter, in the rear position. 3.27 rear im on the fence about switching to 3.55. Trans has notchy shifting but does get better. After 500 miles it showed improvement. Without some work its not the best powershifting trans. I have a cable set up and i found out through experience when i slightly pre loaded the throughout bearing i had a big improvement in power shifting and speed shifting. Thats cable mind you.

[MaSnaka]

I'm still in. Waiting on back ordered short input shaft to use with my existing bell housing. I'm patient.

John

[Lightingrod]

Originally Posted by RET_COP

Tko 600RR steeda tri ax with a nice steeda shifter, in the rear position. 3.27 rear im on the fence about switching to 3.55. Trans has notchy shifting but does get better. After 500 miles it showed improvement. Without some work its not the best powershifting trans. I have a cable set up and i found out through experience when i slightly pre loaded the throughout bearing i had a big improvement in power shifting and speed shifting. Thats cable mind you.

What shifter position; rear-center-front?

[RET_COP]

Rear position

[Lightingrod]

^^Duh^^ Should have read your post a little better!

Do you think the mid position would be better? As in $350.00 better? I looked at your photos and I think the rear position would work for me, I have my seat all the way back!

thanks,

[RET_COP]

You can take some measurements and figure where it would be and see if it's worth it. The rear position worked great for me.

[eschaider]

Originally Posted by RET_COP

I've been on the Ford websites a lot over the years and those guys Hamer the crap out of those transmissions, faceplated and all and i never heard of breaking third gear. Ive seen a lot of carnage in my years of drag racing, could this isolated incident just be a bad third gear from a metallurgy standpoint. I mean this stuff happens. I don't doubt that the .140 is an issue but does it directly result in a breakage problem the we all know about? Im not seeing that.

The torque capacity for a gear set is a function of the steel used, the gear centers, the tooth style and also the face width of the gear teeth. The T56 Magnum has the same gear centers as a regular T56. The box's strength comes from increased tooth face contact (width), improves materials and also tooth pitch angle.

If you have a gear that is 1" wide and you make no changes other than reducing the tooth contact (face width) by 50% the torque capacity of the gear has been reduced by 50%. This is exactly (other than the percentage) what has happened to third gear in the TKO 600's. The torque capacity reduction is linear with gear tooth face width reduction.


Ed