Hello everyone,

I'm building a Lamborghini LP640 kit car on a stretched 86 Fiero frame and I just picked up my 2002 Series II 3800 from a Pontiac GTP. My question is related to transmission choices for my car and I was checking to see if there was anything out there that is better than the stock transmission. I open to options and hoping that you guys can help me decide on whether to keep it automatic and go with a newer replacement transmission or convert everything over to a manual transmission. Personally I like the idea of a manual car but the coversion seems like it would be very complex.

Here are the things that I'm looking for:

1. At least six gears.
2. If I was to stick with an automatic, I would like to use paddle shifters without making the investment in the Master Shifter kit ($2,500). Is there a GM or other tap shift system and transmission that can be used?
3. If converting to a manual transmission, I will need a dependable linkage system and peddals ect.
4. The tranmission should mate up to the 3800 with minimal fabrication (adapter plates are ok)
5. It must be strong enough to handle 350 - 400 HP from the 3800

Any help is appreciated and thanks in advance,

No-Bull

If you're going to stick with auto, you basically have no real options for a 6 speed right now. Sure, the 6t70/6t75 are available with the right bell housing pattern, but they are much more complex transmissions, and nobody has worked out how to control them independently of the ECM with the engine they came bolted to. So if you want a 6 speed, your only real current option is the F40 out of the G6 GTP. No 3800s came with the 6 speed auto.

If you want auto + tapshift, you'll want to stick with the 4t65e. Some cars came with the option, and I believe there has been at least one install using a fabricated paddle shift setup with this trans.

If you want a much easier install, and want a manual, the F23 Getrag is also highly recommended, and much cheaper/easier to install than the F40, as it can use standard axles. For auto though, stick with the 4t65e-HD, perhaps with some upgraded parts.

Just do a little searching...This has been gone over a 100 times over and over.....All you will need to know has been asked and can be found with the search function....

Your "best" bet is going to be a stock 4speed 4t65e, without tap shifting...

Trying to use tap shift is quite foolish due to the fact that you are not running a dual clutch transmission.

Thanks guys.

I did a search and did find a lot of information on this however I figured that it would be best to ask in a new thread since this was a multi topic question (which transmission and auto vs. manual). Also I know that new things are always being tried when it comes to interchanging parts from the bin and I wanted to make sure I was getting the most up to date information.

The help is greatly appreciated and if anyone else has anything to suggest then please feel free to add to this topic.

No-Bull

Since you will have to room, how about you mount everything longitudinal. Get something like a Porsche trans and it should meet your requirements.

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Turbo 3800 E85 5spd spec5
11.53@126.7

search for information on mating a 4t80e to a 3800sc, you can get a transmission controller for $500 that gives you tap shift capability.

quote Originally posted by jasonfox: search for information on mating a 4t80e to a 3800sc, you can get a transmission controller for $500 that gives you tap shift capability.

Nothing any more special about that trans then a 65E....Add more weight for nothing....I agree with Justin.....

quote Originally posted by jasonfox: search for information on mating a 4t80e to a 3800sc, you can get a transmission controller for $500 that gives you tap shift capability.

The "tap shift" idea again is completely impractical, as you get no overrunn when downshifting (engine braking), and you are only going to "tap shift" between 2nd and 3rd gears under any throttle.

The G50 porche trans route is not a cheap one, look at spending well into the 5-8k range just to get a trans in a car, another 1500-2500 should get the clutch/flywheel/adapter plate.

quote Originally posted by MstangsBware: Nothing any more special about that trans then a 65E....Add more weight for nothing....I agree with Justin.....

It's built incredibly tougher than a 4t65e with larger internal components, but yes it does add another 100 pounds which is somewhat parasitic to weight.

Considering they can be had for $50 to $100 I would think they would be an acceptable solution.

quote Originally posted by jasonfox: It's built incredibly tougher than a 4t65e with larger internal components, but yes it does add another 100 pounds which is somewhat parasitic to weight. Considering they can be had for $50 to $100 I would think they would be an acceptable solution.

Tougher than what? A factory stock 65e in my fiero ran faster times than 99.9% of the entire 3800 community for YEARS and YEARS of constant abuse.... A mildly built one should have no problems handling 450whp forever.

The 4T65 got a bad name in the 3800 community because they can and do fail (they have plenty of failure prone parts, just search the web sometime). In the Fiero community, however, the trans is pushing a car 1000 pounds lighter than it was intended to. I believe this is why the 4T65 seems to hold up well in a Fiero. If you try doing this stuff with a Grand Prix or a Bonneville, you will likely destroy the trans after 300-350 hp range.

As for the 4T80, in my opinion, it's too big, too heavy, too complex to wire up electronically, and too expensive to rebuild if needed. But that's just me.