manual transmission swap...suggestions?

[graphicjunki]

Being that my car is just now back up and running, I am trying to decide if I want to keep this beefed up TH400, or get a manual. The 400 is cool, and it shifts PLENTY hard...Plus I love the way the car squats when I put it in gear. But knowing that the TH400 is such a power leach it has me thinking of replacing it. Then I start wondering which way to go...plus, who doesn't like going through the gears of a manual?!

But there are so many options out there for manuals, and I only know about a couple. Mainly the T5 and T56. Both of which are known to have only 300-400lbft thresholds without dumping a ton of $$ into them.

So if you were to do this, which route would you go, with visions of hitting 600lbft torque in the end. Considerations of manual vs hydrolic clutch being kept in mind also.

If I switch out the auto, I'm going to go with a 200R4 or 700R4.

Thanks.

[72SBVet]

You might buy a Viper tranny as the T56 was originally designed for the Viper program. I have a T56 an am going to beef it up with Liberty Gear components.

[tektrans]

th400 does suck up some hp however with a decent converter the 400 will out accelerate any stick shift car any day.
You'll gain some dyno ponies but you'll be slower for sure.

[6880 Mike]

Originally Posted by graphicjunki

...which route would you go...

Keep the TH400.

[gtr1999]

I thought about the same thing when I had my 72's TH400 out years ago. Since I didn't plan on driving more then 1000 miles a year I rebuilt the Th400 and installed a set of 336 gears in diff. It works out pretty nice but then I'm not racing it although I built it to handle about double the hp I have.
The OD would have been nice but I just don't drive it much anymore so it wasn't worth it plus the value is higher with the original trans in it.

If you are going to a manual then you might as well get the OD trans, my son was blowing up ST-10's with 500hp all the time. He now has a Liberty Gear built Tremic which is face plated, he likes it. Me...a M-20 Muncie, 350hp, and 336's is all I would need.

[phantomjock]

Have you considered going with a full manual throttle valve assembly on the TH400? Acts like a clutchless manual.
Just thinking out loud. Options to consider.
This from the TCI web Site:

Making the right shift at the right time is critical to getting the most performance from your transmission. The new TCI® TH400 Full Manual Shift Valve Body with Low Gear Engine Braking is the best way to deliver quick shift response times and clean neutral shifting. Best of all, the full engine braking in low gear is perfect for rock crawling and 4x4 applications where utilizing the engine’s compression drag to help traverse the most extreme terrains is a useful feature.

The TCI® TH400 Full Manual Valve Body with Low Gear Engine Braking is the perfect set-up not only for heavy off road usage, but is great for hot street/strip cars where a forward shift pattern valve body ensures reliable transmission gear selection. As with all TCI® valve bodies,installation is a simple bolt-in procedure for any GM TH400 transmission with all necessary parts included and performance is guaranteed due to the rigorous TCI® quality control standards.

I got their similar set up for my 200-4R. No engine brake but kept my electric lock up for the converter. 4.11 rear end.

Can't wait to LAUNCH!
Cheers - Jim

hehehe I wanna see a C3-rock crawler, but the rest of the info looks very interesting.

[7TRoadster]

TKO 600 5sp with overdrive 5th. Two overdrive ratios are available. Good to 600 foot pounds and there are offset shifter options to fit the Corvettes. Also bellhousings are available for this trans that bolt up to an LSX platform if you ever decide to go that direction.

This would be mostly a bolt in setup, modifying your cross member to be removable will make this a straight forward swap. You may have to mod your drive line or get a special U Joint.

Don't forget you will also need a clutch to support 600ftlb and a bell housing too. $$$$ The bucks add up real quick.

With a bundle of cash under the mattress the biggest challenges will be contorting your body under the dash to swap out your pedal configuration, deciding to go with mechanical or hydraulic clutch actuation and installing either one. Electric switches changed or replaced.

Console components are easy to replace but not necessarily cheap. Maybe a good idea to search here to see if someone has made a list of all the parts you will need for the swap. Differing years will be different of course.

Let's see.............. Trans $2600, clutch, pressure plate, flywheel and bell housing $1500. Hydraulic throw out bearing kit, $450, clutch and brake pedal setup $200 used, console components $400.......... If you do all the work yourself my guess with a new trans $4750 plus or minus 10%.

I'm not trying to throw water on your fire, just consider all the work involved and costs associated before deciding the swap is a good idea. An old mans $.02

I'm not an auto guy so cannot give any direction on moving to one of the later model autos. Seems easier than a swap over to manual but that is just a guess.

Best of luck and keep us posted on what you decide.

[72SBVet]

Shop around for pedal assemblies as I got mine off of eBay for around $90 shipped. Changing the pedals is a pita, but I'm stripping my car down to nothing so it'll be easier for me to do.

[graphicjunki]

Wow... You guys really know how to squash an idea! LOL!

I believe that the trans already has some kind of shift kit in it, as I said...even when it ran like crap, when it shifted from 1st to second it slammed. I went to TCI's web site and saw their street fighter valve body. Gives you manual/auto. My father in law swears it has this already...I will have to check because I haven't yet. But if it doesn't, maybe I will look into that.

It just sucks to know that I'm losing as much as 50 hp!

Thanks.

[72SBVet]

From what I'm understanding your Turbo 400 is already rebuilt?....I'm selling mine so whatever I get will go towards my current T56. I dumped $1800 into the 400, but even though it's a race ready trans I want to shift gears not just leave it in D and go. Good luck on whatever you decide to do

[graphicjunki]

I only know what I've been told. And from all the crap I've come across on this car, I'm not really believing anything until I know first hand. I've never driven anything with a TH400...so I don't know how they behave normally. But when I got the car it ran like crap. Even then, when it shifted from 1-2, it slammed you into your seat. My father in law told me that he was told it had a shift kit and a auto/manual valve body.
I have only driven it in D...so I can't attest to the valve body.

[tektrans]

well you cant put a manual valve body equipped trans in "drive" as far as I know. U probably have a shift kit in the trans. U'd have to shift a MVB it into the gear you want and you'd need a different shifter like this one so you could hit it into gear without overshifting into the next gear.

[phantomjock]

I did a similar research effort before making my full reverse manual-throttle body (RMVB) choice for my auto. There is a real good thread over at Pirate4x4 that specifically relates to the TH400. You might consider looking it over; "The DEFINITIVE TH400 valve body/shift kit thread" rather than copy and post some here. Shows some nice gated shifters - but I'm going with a ratchet shifter B&M Stealth Pro for my install. I'll start a thread when I get to the interior.

Cheers - Jim

[graphicjunki]

That was a great read. Thanks! I'm thinking the pro kit...

[tektrans]

Mine is rmvb as well.