Tremec TKX transmission

celentanogj · #1 (**permalink**) 11-24-2021, 01:41 PM

Looking for some info on the TKX tranny, anyone using the TKX?
I have a 428 would like to know if it's worth the time and money to swap out my Richmond tranny (5th gear is 1-1) for the TKX unit.
Btw my rear end ratio is 2.88

Grubby · #2 (**permalink**) 11-24-2021, 05:09 PM

You will need to change rear gear to. Expensive swap.

If you really don’t like the Richmond - do it.

If the Richmond operates well, you really wouldn’t gain anything by swapping. Yours acts like the TKX w/3:54 rear.

John

Bojets · #3 (**permalink**) 11-25-2021, 06:29 AM

Love mine

cycleguy55 · #4 (**permalink**) 11-25-2021, 09:47 AM

If I was starting over I'd go with the TKX. I have a Richmond that was just re-built, so I'm sticking with that.

eschaider · #5 (**permalink**) 11-26-2021, 08:49 AM

Quote:

Originally Posted by Grubby

You will need to change rear gear to. Expensive swap.

If you really don’t like the Richmond - do it.

If the Richmond operates well, you really wouldn’t gain anything by swapping. Yours acts like the TKX w/3:54 rear.

John

And your Richmond, with its 1:1 fifth gear, is physically stronger in top gear (1:1) than the TKX is in either of it's two different (0.82 and 0.64) overdrive top gears — not that any of us do a lot of performance style driving in top gear.

Ed

ERA174 · #6 (**permalink**) 11-26-2021, 10:00 AM

Depends on what you’re looking to accomplish. If you just want lower rpm at highway speed, you may be happy with the TKX with 0.82 overdrive and your current rear differential gear ratio. You will first need to evaluate if your current engine configuration will be happy running at the lower rpm. You should play with some of the calculators available online to compare what you currently have and where you’re looking to go. This calculator is one of the more basic ones. https://spicerparts.com/calculators/...rpm-calculator

eschaider · #7 (**permalink**) 11-26-2021, 01:51 PM

You may want to be a little circumspect about the use of the Spicer calculator. If you put in a ring and pinion gear ratio of 2.73 with a tire height of 711mm (28 inches), set the engine RPM to 2000 rpm and use a 0.82 over drive for the top gear in the transmission, the Spicer calculator has you at essentially 120mph (119.74).

For the same specs the Tremec calculator puts you at 74 mph and the Second Strike gearing calculator puts you very close to the Tremec numbers although you need to scale the output because they do not offer a 2.73 ring and pinion alternative.

FWIW real world driving experience lands between the Tremec and Second Strike numbers. Online calculators are definitely useful, they just need to be validated before using. Some are better than others. I would have expected the Spicer calculator to be spot on but — it wasn't.

Ed

ERA174 · #8 (**permalink**) 11-26-2021, 03:52 PM

“Spicer calculator has you at essentially 120mph (119.74).”
Ed, I believe you input one of the parameters into the Spicer calculator incorrectly. When I used the Spicer calculator it appeared to me to be accurate.
Also, additional advice to OP, evaluate what first gear in a TKX with your 2.88 differential ratio will do to the hole shot compared to your current transmission, can you live with any difference? I have a 3.08 rear differential and went from a close ratio toploader to a wide ratio toploader, which suited me better.

nkb · #9 (**permalink**) 11-28-2021, 09:10 AM

I found this calculator very useful in assessing transmission gear ratios, diff ratio, tire sizes: http://westfield-world.com/Gear_ratio_shifts.xls

Provides speeds in gears and rpm changes between gears at selected shift points. Validated against my real world experience.