Replacement transmission

[celentanogj]

In my CCX cobra I have the old Rchmond 4+1 transmission ( 5th gear is 1-1), so far the tranny is operating great but I found out that Richmond has not made replacement parts for this tranny for several years and so far I haven't found anyone that stock parts for the unit. My question is what would be a good replacemnt for the tranny? As I said the tranny so far is working great (knock on wood) but just in case something happens what would be a replacement? The cobra has a 2.88 rearend so most OD's wouldn't work well, I was thinking of just going to a WR toploader. The Richmond has the 26 spline input and the rear is 32 spline. Additional info on the vehicle it has the 428FE tq was rated at 544.

[C5GTO]

I just replaced a Richmond 4+1 in my Cobra with a Tremec TKX. The old trans is just sitting around collecting dust. I believe all the parts in it are fine. If you'd be interested in a "spare parts" trans, I'll make you a good deal on it.

I did the replacement as the car has 3.5 rear end ratio and it did need the OD to keep RPMs within reason at highway speeds.

Send me a PM if interested and we can work out details.

[C5GTO]

I just replaced a Richmond 4+1 in my Cobra with a Tremec TKX. The old trans is just sitting around collecting dust. I believe all the parts in it are fine. If you'd be interested in a "spare parts" trans, I'll make you a good deal on it.

I did the replacement as the car has 3.5 rear end ratio and it did need the OD to keep RPMs within reason at highway speeds.

Send me a PM if interested and we can work out details.

[eschaider]

OP, I think Joel may have the short way home for you if you guys have the same gearsets in your boxes. Spare Richmond parts are always good to have around. Depending on the different ratios Richmond offered, it is possible that you two may have a parts swap ability that will look more like a remove and replace.

I use a 2.73 R&P with a TKO (same as a TKX ratio-wise) that has the 0.82 overdrive. With a 295 x 55 rear tire 2000 rpm in fifth gear is right around 70 mph. Not as good as my BMW, but if I want that, then a 295 x 65 tire brings me in around 1850 rpm at 70 mph.

Be careful of too tall a gearing. If your idle is lumpy and does not smooth out until about 2000 rpm, then you want to be cautious about using top gears that drop you below 2000 rpm on the highway. On the other hand, if you have good low-speed engine torque, the RR trans and your 2.88 are a dream made in heaven.

One more follow-on thought: With the Tremec's 2.87 first gear (in both the TKO and TKX), even a 2.88 R&P will provide you with an 8.27 first gear, which makes for a pretty frisky first gear experience — something to consider?

[celentanogj]

Thank you for the response. I am using 295/50-15 which are 26 1/2" diameter, I was considering the TKX, when if I get to that point I'll have to do more research in the fitment of the TKX in the cobra. I have a Lakewood bellhousing currently with the Richmond transmission and I'm, sure that it's not just a matter of swapping in the TKX and all will fit.

[eschaider]

If you can find a 295x55 tire, your tire diameter will be closer to 28 inches. The for sure selection for that diameter is M/T 295x55 ET STREET® S/S tire.

[Grubby]

I think you will need more gear with a TKX. I have a moderate built 427 with 600 horsepower and 3:54 rear. ERA recommends 3.31 or 3.54 with their builds.

For what it is worth, I would try to work a deal on the Richmond trans noted above.

John

[CHANMADD]

My rear wheels are 27" diameter. I got the TKX with the 0.068 od. My rear is a 2.88 lsd. Its awesome for me,. 80mph in 5th gear is about 1800 rpm, 2000, gives close to 90.. very easy cruise on the freeway , even with the sidepipes.

[eschaider]

Originally Posted by Grubby

I think you will need more gear with a TKX. I have a moderate built 427 with 600 horsepower and 3:54 rear. ERA recommends 3.31 or 3.54 with their builds.

For what it is worth, I would try to work a deal on the Richmond trans noted above.

John

I think our seat of the pants dyno is significantly impacted by low-speed engine torque, John. If the engine was built for bottom end and midrange torque, it should be OK. On the other hand, if it was built for midrange and top-end, maybe not so much.

I should have elaborated on that a bit more. Typically, if you have a problem with smooth, predictable engine behavior below 2000 rpm, the engine was probably built as a midrange / top-end performer, and you are spot on; it will take a taller gear to get the car to perform the way our seat of the pants dyno would prefer. On the other hand, if you have a robust low-speed torque curve, the engine won't even break a sweat.

PD-blown engines, whether using Screw or Eaton TVS rotors, would be examples of engines with robust low-speed torque. N/A engines with frisky cams would be examples of engines at the other end of the spectrum with robust midrange and top-end power but lacking in low-speed torque.

Strokers with moderate camming will fit the middle ground very nicely and provide you with good low-speed power, although you might prefer a R&P that looks more like a 3.08 or so.