Does the new Tremec TKX fit the latest MK4?

[elspanishgeek]

Hi,

Title says it all! I'm reading that there a few different dimensions for the new Tremec TKX compared to the TKO and was wondering if it fits and mounts just like the TKO on the latest kit for the MK4 Roadster? Also if the Tremec 500/600 compatible driveshafts work with it? Though I'm guessing this one is true given that both have a 31 diameter output spline.

Many thanks in advance!

[CaptB]

Boy I hope so, I just ordered a Blueprint 347 and TKX. The salesperson advised that it was a direct replacement for the TKO..

[edwardb]

Everything I've read and seen confirms the TKX has the same length, input shaft dimensions, spline counts, bell housing pattern, and feature set as the TKO. Doesn't have the rear mounts that have to be cut off the TKO. Also doesn't have the option for the very front location for the shifter. But I've never seen a build that used that. Same options for the reversible rear shifter and a midshift. The case has a smaller cross section, but since the TKO fits obviously the TKX should fit even easier. Maybe make it a bit easier to drop out just the transmission () which gets talked about quite a bit.

All looks good to me and with the new features certainly seems like the right choice once they become more widely available.

[CaptB]

Everything I've read and seen confirms the TKX has the same length, input shaft dimensions, spline counts, bell housing pattern, and feature set as the TKO. Doesn't have the rear mounts that have to be cut off the TKO. Also doesn't have the option for the very front location for the shifter. But I've never seen a build that used that. Same options for the reversible rear shifter and a midshift. The case has a smaller cross section, but since the TKO fits obviously the TKX should fit even easier. Maybe make it a bit easier to drop out just the transmission () which gets talked about quite a bit.

All looks good to me and with the new features certainly seems like the right choice once they become more widely available.

What you posted is what I understand is the ground truth. Would be nice to have someone that's successfully installed a TKX sound off but there may not be anyone who's done that yet.

[GoDadGo]

Guys,

If I can stuff a ZF S6-40 in a Roadster, then a TKX should be a breeze to install because the ZF is the same length, but a lot fatter.
If I were to do a future build, the TKX would be the likely transmission since the ZF Gearbox has been out of production since 1996.
I really think the TKO 500 & 600 series will be going away as the newer TKX gains popularity.

http://www.zfdoc.com/techinfo.htm

Steve

[ggunter]

Steve, off topic but I was just looking at your car and I like your side view mirrors. They appear pretty functional. Where did you get them and is the right side mirror convexed?

[GoDadGo]

Steve, off topic but I was just looking at your car and I like your side view mirrors. They appear pretty functional. Where did you get them and is the right side mirror convexed?

Gary,

The mirrors are for a 356 Porsche and do come in Flat and Convex types and they do work well with No Shake What So Ever!

https://sierramadrecollection.com/35...T5-p20310.html
https://sierramadrecollection.com/35...T5-p18328.html

I did Flats on both sides and wish I would have gone with the Convex type instead, especially on the passenger side.

Steve

[elspanishgeek]

Guys,

If I can stuff a ZF S6-40 in a Roadster, then a TKX should be a breeze to install because the ZF is the same length, but a lot fatter.
If I were to do a future build, the TKX would be the likely transmission since the ZF Gearbox has been out of production since 1996.
I really think the TKO 500 & 600 series will be going away as the newer TKX gains popularity.

http://www.zfdoc.com/techinfo.htm

Steve

Steve, I will be calling Blueprint next week to schedule my 306 (or 347, I'm still flip-flopping every other day, hahaha) with the new TKX. Looks like I may be one of the first ones? Will definitely share my experience with it!

Everything I've read and seen confirms the TKX has the same length, input shaft dimensions, spline counts, bell housing pattern, and feature set as the TKO. Doesn't have the rear mounts that have to be cut off the TKO. Also doesn't have the option for the very front location for the shifter. But I've never seen a build that used that. Same options for the reversible rear shifter and a midshift. The case has a smaller cross section, but since the TKO fits obviously the TKX should fit even easier. Maybe make it a bit easier to drop out just the transmission () which gets talked about quite a bit.

All looks good to me and with the new features certainly seems like the right choice once they become more widely available.

Helpful as always, Paul! Thank you!

[CaptB]

Steve, I will be calling Blueprint next week to schedule my 306 (or 347, I'm still flip-flopping every other day, hahaha) with the new TKX. Looks like I may be one of the first ones? Will definitely share my experience with it!





Helpful as always, Paul! Thank you!

Here's a little math that I did when deciding to order the 306 or the 347 (all costs were option 2-carb'd with the TKX):
302 cost $9,664 which is 235HP and costs $41.12 per HP
306 cost $12,980 which is 370HP and costs $35.10 per HP
347 cost $13,780 which is 410HP and costs $33.60 per HP
427 cost $19320 which is 485HP and costs $39.83 per HP

My point is that the difference between the 306 and 347 is $800 more and you are adding 40 HP at the lowest per HP cost of any engine they have.

I just ordered the 347 w/the TKX. They told me 10-12 weeks on delivery. They said if I ordered a 302 or 306 that time would be longer because those engine models make less money and they are so busy they are building the money making engines (347) before the others.

Good luck in your choice.

[GoDadGo]

Here is a recent video that the Holley Performance Group put out on the TKX Transmission.

https://youtu.be/FQbqXbav_jk

[elspanishgeek]

Here's a little math that I did when deciding to order the 306 or the 347 (all costs were option 2-carb'd with the TKX):
302 cost $9,664 which is 235HP and costs $41.12 per HP
306 cost $12,980 which is 370HP and costs $35.10 per HP
347 cost $13,780 which is 410HP and costs $33.60 per HP
427 cost $19320 which is 485HP and costs $39.83 per HP

My point is that the difference between the 306 and 347 is $800 more and you are adding 40 HP at the lowest per HP cost of any engine they have.

I just ordered the 347 w/the TKX. They told me 10-12 weeks on delivery. They said if I ordered a 302 or 306 that time would be longer because those engine models make less money and they are so busy they are building the money making engines (347) before the others.

Good luck in your choice.

You are right, the 347 is the best deal, but I'm also concerned with 400HP+ on a car that is barely over a ton. I want to be able to use 5th gear! I want the car to bite but not maul. And I know that is a completely individual experience, not commenting that there is a right or wrong here. My hesitation is just if the 347 is just gonna be too much.

[edwardb]

You are right, the 347 is the best deal, but I'm also concerned with 400HP+ on a car that is barely over a ton. I want to be able to use 5th gear! I want the car to bite but not maul. And I know that is a completely individual experience, not commenting that there is a right or wrong here. My hesitation is just if the 347 is just gonna be too much.

No, 400 HP is not too much. Sure you can have less and still have a blast. Once completed, you won't see too many taking power out of their builds. Usually they're adding power. Start with a reasonable amount IMO. That pedal on the right in the footbox? That's the accelerator and you get to decide how much of that HP to use. How much is too much is talked about a lot. And I agree that crazy numbers are often on the edge of performance and the power is not easy to manage. But a well tuned 400 HP 347 IMO is not hard to manage and in the sweet spot for a pushrod engine. Had one in my #7750. A bit more than 400 because it was a higher end build. But it was a great runner and loved how it fit into the chassis.

Not sure what you're concern is for 5th gear. Again, properly tuned and with the right trans and diff ratios, will cruise with ease. I'd recommend the 0.68 5th gear TKX and 3.55 diff. A well proven combination. Plenty quick but also cruises at a decent RPM.

[elspanishgeek]

CaptB and Paul, y'all convinced me! Just put down the deposit for a 347 and asked them to swap the TKX they offer with the 0.81 5th gear to the 0.68 one. I knew this forum was gonna be an awesome part of the experience but I wasn't expecting it until I actually started the build. Thank you for sharing your advice!

Now gotta find some Cobra/Powered by Ford covers, hahaha.

[Jim1855]

Another very good review that should answer most questions.

https://www.youtube.com/watch?v=ryeUq3tGNQw

Size, shifting, gearing and many other differences, upgrades and similarities are offered.

It's a bolt in replacement for the TKO-5/600 with benefits.

Jim

[CaptB]

CaptB and Paul, y'all convinced me! Just put down the deposit for a 347 and asked them to swap the TKX they offer with the 0.81 5th gear to the 0.68 one. I knew this forum was gonna be an awesome part of the experience but I wasn't expecting it until I actually started the build. Thank you for sharing your advice!

Now gotta find some Cobra/Powered by Ford covers, hahaha.

Nice job! I can't wait and it's a long 10 weeks plus, but I'm looking forward to its arrival.

[juddster]

Mike Forte is always a good resource for these type of questions.

[CaptB]

Mike Forte is a good resource for nearly all questions.

FYI, I ordered my 8.8 from him and along with the Blueprint 347/TKX I'm confident I've spend my money wisely. He's got engines too, albeit at a higher price, but by the time I talked to him about my axle, I'd already ordered from Blueprint.