Car currently has a 5 spd. I may want to convert it to an auto. Yes, I know that's weird! 
What bolt-up options do I have for a transverse transmission that can take some drag racing abuse, bolt up to a 3800, minimal communication with the ECU, and has simple after-market support?
I'm seeing:
4T60-E
4T60E-HD
4T65-E
4T65E-HD
But I don't know the advantages/ disadvantages to each.
Any others??
The TH125 takes a fair amount of abuse and is light. I believe that a 2.8L converter will bolt to your flywheel and give you about a 2700rpm stall.
Look at 1988 Cavalier
Maybe I should have mentioned I will have about 300 hp.
In reply to John Brown:
I can't use the flywheel. It's a custom piece, and not OK with the NHRA. I need to convert to a flexplate.
Fair to assume either the TH125 flexplate or the 3800 flexplate will work?
300hp is no issue. Many V8 Fieros have gone 11/12's with TH125s.
Yes flexplate (honestly I was half asleep at my desk writing that) and I believe there is an SFI version of the flexplate through someone.
Actually, let me reword something...
My mention of the ECU may sound like I am computer averse. That's not correct- I actually need to be able to shift the trans with an after-market computer.
What I meant was I don't want a modern trans that is married to the ECU or the VIN. I need to have something I can modify (and I'm not too smart), but also shift electronically (after-market).
4t60e(or 65e) can be controlled via non gm computer means. I know a guy that built a simple circuit board to paddle shift one, knowing which solenoids in the valve body are powered for which gears.
For race only i would consider the 125 as it has less working parts and less weight by far. The only thing it has computer control is converter lockup much like a 80's lockup th350. The 4t60 non E needs a properly adjusted tv cable like a 700r4 or itll burn up
I know plenty more f 5-6 speed swapped L67 cars. Why is the flywheel custom? I thought they just used a 3.8 camaro one.
If you don't need overdrive the TH125 is still pretty much the unit I would suggest.
It's durable, efficient and cheap if you do break one!
patgizz wrote: Why is the flywheel custom? I thought they just used a 3.8 camaro one.
Because FWD?
I don't know. I didn't put it in there.
In reply to John Brown:
You've got mail (and I have no idea why I don't have your email address) 
In reply to patgizz:
Yes, the paddle shift is kind of the idea.
SVreX wrote: In reply to patgizz: Yes, the paddle shift is kind of the idea.
I remember mocking Guido with a paddle shifter idea, considered sending him a miniature oar to go with the boat anchor he was building... he certainly outperformed my expectations 
In reply to John Brown:
I didn't say paddle shift IS the idea, I said KIND OF.
And I don't plan on making a paddle shifter out of a dildo.
Well, i could see building a shifter that has micro switches on it where each position switches the solenoids to command one gear. I have a plethora of gm service manuals and wiring diagram books with trans stuff for the th125 through the 65e.
If you wire them wrong you get limp mode, leaving you with 2-3 only. I did that once. Finally someone can use my knowledge of fwd gm trash! I really would love to build one more all out fwd gm car, i miss my 5 speed turbo grand prix. Was actually considering an L67 GTP last week, then I remembered i have 11 cars. Wish i had something to offer for the 5 speed but we just sold a good 4t65e to my dads neighbor.
There are different final drives based on the platform too, and there is a magic combo of chain and sprockets to the final drive that make a 3.73FDR. I had one built like that and it turned the 3.4 dohc from sleepy off the line to hard pulling all the way through.
patgizz wrote: There are different final drives based on the platform too, and there is a magic combo of chain and sprockets to the final drive that make a 3.73FDR. I had one built like that and it turned the 3.4 dohc from sleepy off the line to hard pulling all the way through.
Is this the 4t65E that has the adjustable final drive? Although a chain sounds breakable......
In reply to bentwrench:
They used that trans in the supercharged full size H body stuff, 300hp shouldn't be an issue.
The chain is arguably the strongest part of the transmission
patgizz wrote: 4t60e(or 65e) can be controlled via non gm computer means. I know a guy that built a simple circuit board to paddle shift one, knowing which solenoids in the valve body are powered for which gears.
The GM Ecotec performance manual TELLS you how to do this. After you adapt a 4T60 to the engine, of course.
patgizz wrote: The chain is arguably the strongest part of the transmission
When I was talking to some front drive 3800 drag racers, they told me that the chain breaks fairly readily and there are upgrades available.
This is at somewhat north of 300hp, admittedly.
Rest of the trans gives up much quicker, i've nuked several of them in the 300hp range 
Plus slicks. Those guys break constantly. Axles, diffs, pretty much anything in a 4t60e breaks on slicks with cranked up boost
Ayup.
I was considering an AWDized one for the middle of my Rabbit. (Long story) I got scared off by the tales of breakage and breakage and breakage, given that I wanted silly Group B power (big turbo + supercharged 3800) in a small mid engined car. The Porsche 930 CV joint adapters looked very nice, though, and adaptable to driveshaft flanges.
But the tales of breakage... never mind!
There's always the 4T80 but that trans is a gigantic beast, like a modern day TH425.
This is for racing. Lightweight, strong, and easily serviceable all count.
So far, looks like the TH125 is winning...
You'll need to log in to post.
