Verdict on current TKO 600 Transmission?

[Anthony]

Originally Posted by decooney

Received an email today that set the record straight for me, with a picture. It sounds like any of the reputable transmission distributors for Tremec have an explanation, details, and reasons behind the locking in gear issue, and the breakage, along with the 3rd gear alignment issues. No further questions.

So what is your decision?

[decooney]

Answer: Proceeding with a new TKO 600, and much less concerned now in a light car. Apparently they have changed a shift fork as well, and noted the gear alignment change as being a planned change. Thanks,

[Excaliber]

There was a REALLY long thread on these issues, particularly about 3rd gear alignment and breakage (see above pic).

There was no "explanation, details, and reasons behind the locking in gear issue" offered by any of the any of the "reputable transmission distributors for Tremec" in that thread or on Club Cobra.

Not sure what that means, but it doesn't feel warm and cozy...

[Jimi G]

Alright guys here is the official answer on the alignment of the third gears, this is the answer I personally received from Tremec. The reason the third gear on the cluster is over a little bit is to allow for the machine that cuts the teeth into the gears. The original 3550's had a two piece cluster which allowed the gears to butt up to one another, but since it was a weaker design than the new one piece cluster they changed it. He also informed me that even though the gear is shifted a bit it did not compromise the contact surfaces between the upper and lower gears. I tried to load a picture of the two shafts but it was to large so I put it into my photos for all to see. I hope this clears things up a little.jimig@standardtransmission.com

[Greg Haile]

Jimi G,

Thank you for the time and effort you've put in on this topic. As a TKO owner who has yet to get on the road, the information you provide is invaluable.

Greg

[Jimi G]

Greg,

Thank you for your kind words Greg, if you or anyone else has anymore questions feel free to let me know, that is what I am here for. jimig@standardtransmission.com

[Excaliber]

Thanks for the explanation Jimi. Heres your pic from your gallery.
Open the pic, right click, select properties, COPY the URL, back here, select 'image', paste.

It appears that 3rd gear is indeed offset toward the rear, due to machining requirements (bottom pic). I assume the TOP pic is the old two piece counter shaft. However, from your explanation it appears that the new one piece results in a stronger counter shaft and is not an issue with 3rd gear breaking teeth.

[keislerNick]

I thinkthe top pic is a 3 piece countershaft.

[Excaliber]

Oh, the old counter shafts were THREE piece? That do sound like a 'weak link'.

[decooney]

Thanks for setting the record straight, Jim.

DC

[Anthony]

Originally Posted by Excaliber

It appears that 3rd gear is indeed offset toward the rear, due to machining requirements (bottom pic). I assume the TOP pic is the old two piece counter shaft. However, from your explanation it appears that the new one piece results in a stronger counter shaft and is not an issue with 3rd gear breaking teeth.

Do you mean 2nd gear?

I think third gear is the first gear on the left. Second gear is the middle gear, and first gear is the gear on the right. Fourth gear (the gear that meshes with the input shaft gear), is just off the picture, on the left

[Excaliber]

OK, 2nd gear is offset toward the front. Point is, the new one piece counter shaft appears to not 'line up' as precisely as the old 3 (or is it 2?) piece counter shaft gear did, for THIRD gear.

However, as Jimi G noted, apparently this is not a serious problem and is not the end reason for at least some trans 'stripping' the teeth on 3rd (as the pic I posted shows).

What the end cause of a trans stripping 3rd gear actually is remains debatable I guess. To heavy a car? Power shifting? Missed shift? Partial shift?

One of the important original questions that arose from the previous thread was: "Is the slight 'mis-alignment' of 3rd gear teeth within acceptable design parameters, is it 'normal'?" Apparently it is within design parameters and it is 'normal' and does not impact the overall strength\rating of the transmission.

[Anthony]

Originally Posted by Excaliber

OK, 2nd gear is offset toward the front. Point is, the new one piece counter shaft appears to not 'line up' as precisely as the old 3 (or is it 2?) piece counter shaft gear did, for THIRD gear.
.

I believe you mean second gear is offset towards the rear, as the right side of the picture is I believe towards the rear of the tranny. The left side of the picture is towards the front.

[hssss]

Originally Posted by eschaider

I just checked my new TKO 4617. The countershaft alignment problem that Greg (Fordfan) has also exists in my new, never used, still in the box untill I opened it TKO.

My transmission appears to have the countershaft shimmed backward towards the rear of the case. The effect of the apparent shimming was to share the total misalignment between second and third gear rather than having third gear absorbing the total misalignment. Come to think of it, the rearward placement of the countershaft will affect every mainshaft gear that meshes with it!

When I bought the transmission the reseller strongly encouraged me to have them 'blueprint' the box before shipping. The cost was just under a hundred bucks. For cheap money I thought what the heck, why not, its just good insurance in case the factory missed something that could come back to haunt me later.

I am now of the opinion the reseller already knew of the problem and in 'blueprinting' was attempting to stack the longevity deck as best as possible by spreading the load reduction across multiple gears, given the Tremec design flaw.

This problem appears to be a Tremec design error. More significantly it defies rational thinking that the folks at minimally Tremec and probably Keisler were unaware of the design error. It is even more troubling that Keisler would misrepresent the cause of failure as a partially engaged third gear resulting from a missed shift.

What each of us, with a TKO 600 TCET4617 appears to have is a transmission with a faulty countershaft design that does not fully engage the tooth face of one or more mainshaft gears. Greg (Fordfan) was aggressive enough in his cry for help and the potential of a broad based foul play that at least one of the websites he posted on (Club Cobra) unraveled the ball of fishing twine.

Keisler is a major disappointment, along with Tremec. It could well be that Tremec advised their dealer network that Tremec would not honor warranties for failed third gear gearsets. The dealers, in this case Keisler, in turn then assigned the cause of failure to the owner with misrepresentations and disingenuous statements because they wouldn't/couldn't carry the expense of warranting Tremec's design error.

Tremec has the real responsibility to both stand good for the repairs and most importantly to produce a countershaft replacement that engages all mainshaft gears correctly. Resellers like Keisler need to be very carefully scrutinized to determine if they deserve our business. Keisler's behavior and deliberate attempts to obfuscate the truth really give reason for pause and reflection.

Ultimately each of us will have to make his own decision. When you do, think about the events that have transpired here, put yourself in Greg's (Fordfan's) place and ask yourself if this is fair treatment and how would you feel if the tables were turned. Remember that if you have a TKO 600 (and probably 500 also) this failure could be just down the road waiting for you!

Ed

Tko600 Warning!!!!

[Eliems]

Mine seems to be the TCET 5008, installed last spring, is this the same TKO 600 having all the problems?

[hssss]

I'm building a 1400 lb car with 500+hp/tq and 315 R1s my answer is to use a fresh T5 I have till it breaks or I have the $ for a Gforce T5 with Dog Face gears. I like how the T5 shifts better anyhow.

Power shifting? Missed shift? Partial shift? All these would result in the syncro teeth on the gear being worn and that dosn't seem to be the case.

[JAC]

Mine is the 5008 model also, hope it's ok.

[eschaider]

When manufacturers test their designs they will typically test to failure. The test they use is normally a continuous load test. When we use our transmissions in the ways that we do when we drive our cars we do not subject the transmission to a nice smooth continuous load like grandma on her way to church.

I am not privy to the Tremec test results but I would be surprised if the transmissions would not support somewhere between 2x and 3x their rated torque capacities under continuous load. I also suspect the ultimate failure point to be closer to 2x than 3x.

When ever you transmit power through two gears the heat treatment, gear material, tooth design, gear face (tooth) width and center to center distance between the two gears determines their strength and ultimate torque transmission capability.

Jimi G from Standard is telling the story straight! The folks at Tremec cut corners for manufacturing simplicity and cost when they went to the one piece countershaft. The gear hob (the tool that cuts the teeth) needs a chip channel to push out the chips from the freshly hobbed gear. With out the chip channel the cutter would bottom and jam or break in the freshly cut chips.

Remember how to determine load capacity for the gear set from my paragraph 3 above. If you cut the face contact by 50% you have 50% of the torque capacity of the same gear set with full face contact. Why do you think Tremec lines up all the other gear sets correctly. Third is the bastard child, sacrificed for manufacturing cost reductions.

Look at the gear set alignments in a Jerico five speed at this url http://www.jericoperformance.com/5.html there are no misalignments. Check the Liberty site at http://www.libertysgears.com/picture.htm again no misalignments. These are purpose built performance transmissions. The Tremec units we have purchased should employ comparable design quality. They don't have to be as strong, they certainly don't cost as much. But the design should not cut corners.

Because we do not use these transmissions like grandma on her way to church the continuous load failure model can be misleading. The shock loads on a gear change under power are much more damaging to the transmission than a continuous load from the same engine car combination. This is further aggravated if your tires are hooked up with a good clutch and a clean but fast shift into third gear. That clean fast shift puts spectacular momentary loads on the gear. Anything less than full tooth contact is a significant reduction in gear life.

Think about it. If Tremec did not need the face width why did they spend the money in steel, tooling, manufacturing time and engineering time to put it there. Across thoudands of units this is not inconsequential! The real answer is the gear tooth face width was not an accident. It was an intentional design decision necessary to support planned torque loads. When manufacturing got the job of making the unit they discovered the design engineer and the manufacturing engineer didn't communicate as well as they should have. The short way home was to offset the countershaft gear and get on with manufacturing.

You and I are the victims. First and second without drag tires are hard to hook up. Third gear is a different story. Make a fast clean shift into third under power without breaking the tires loose. The outcome could be quite devastating for third gear. Like Bogart said in Casablanca, 'maybe not today or maybe not tomorrow, but someday'. I think someday is closer than we may think.

Unlike Keisler's representation of a missed shift causing the damage, quite to the contrary a clean shift under power with the tires hooked up and enough torque is what will kill third gear.

From what Tremec told me the TKO500 and TKO600 both suffer the misalignment.


Ed

[Anthony]

Originally Posted by eschaider

When ever you transmit power through two gears the heat treatment, gear material, tooth design, gear face (tooth) width and center to center distance between the two gears determines their strength and ultimate torque transmission capability.

Remember how to determine load capacity for the gear set from my paragraph above. If you cut the face contact by 50% you have 50% of the torque capacity of the same gear set with full face contact. Why do you think Tremec lines up all the other gear sets correctly. Third is the bastard child, sacrificed for manufacturing cost reductions.

Because we do not use these transmissions like grandma on her way to church the continuous load failure model can be misleading. The shock loads on a gear change under power are much more damaging to the transmission than a continuous load from the same engine car combination. This is further aggravated if your tires are hooked up with a good clutch and a clean but fast shift into third gear. That clean fast shift puts spectacular momentary loads on the gear. Anything less than full tooth contact is a significant reduction in gear life.

Unlike Keisler's representation of a missed shift causing the damage, quite to the contrary a clean shift under power with the tires hooked up and enough torque is what will kill third gear.

From what Tremec told me the TKO500 and TKO600 both suffer the misalignment.

We are not talking about a 50% reduction in tooth contact area, maybe a 5-10%, and I'm not sure that at these smaller levels of misalignment the reduction in strength is linear with the reduction in contact area (length). You may be right though. A mechanical engineer needs to respond. The failure may have occurred even if the gears were aligned properly, but that still doesn't excuse the misalignment issue.

In addition, although I think the torque capability is related to the distance between gears, I would think specifically, it's the radius of each gear factoring in the amount of torque multiplication, based on its ratio, which determines the actual force on the gear teeth, possibly different for each gear set. If you have 500 ft lbs out of the engine, if 1st gear is 3:1, then you should have close to 1500ft-lbs coming out the tail shaft. The actual forces on all the teeth from the input shaft to the output shaft should be calculatable, because the power is being transmitted through 4 gears ( two sets of gears). This would give the relative loading of each specific gear.

[RICK LAKE]

If there is no problem with either of these trans, why are a couple of trans shops selling updated kits with straighter gear angle and different designed shafts. G-Force is one, there are a couple of others. It seams under semi normal driving this trans holds up ok. Under racing conditions that's another story. Has anybody checked the fluid or drain plug for metal? Do you guys change the trans fluid once a year? Who is running what fluid wieght? Any additives being used? The kits say that the HP and torque ratings are up in the 900 hp after the kits are installed. Need more real data for this problem. Rick Lake Happy Holidays