Questions about a Manual Swap (Page 1/2)
MichiganReefer FEB 15, 07:38 PM
Hi all. I have an 88GT Auto that I'm going to be doing a fresh build of an L67 and swap it into my car. I have the 4t65e-hd that came with my engine, and my initial thoughts have been to just have it rebuilt by a shop and run it because it's an easy thing to do with the mounts available all over. I'm now having second thoughts because these transmissions have historically been unreliable and came to the thought of manually swapping my Fiero. I know this is a big job and far easier to buy another Fiero that already is a standard transmission, but I'm curious how involved it is. I've looked at some historical posts, but I have some questions. I know I need the clutch pedal, master cylinder, slave cylinder, and hydraulic lines right of the bat.

1) What I want to know what manual transmission, at this point in time, is my best option to pair with a built L67 I expect to have about 350whp? I see the 5 speed getrag, F23, and F40 seem to be the most mentioned in previous posts.

2) Where can I find mounts for the respective transmission, and do they bolt directly to the 3800 flange?

3) What is my best option for the shifter mechanism?

4) Any other things I should be considering?

[This message has been edited by MichiganReefer (edited 02-15-2022).]

olejoedad FEB 15, 08:35 PM
Historically unreliable?
MichiganReefer FEB 15, 09:45 PM
Not from personal experience, but the impression I got from reading old posts- people need to rebuild them frequently. Clutch plate related things. If my impression is wrong, I'm happy to use the 4t65e-hd I have. I take it you've had positive experiences with it?
olejoedad FEB 15, 11:23 PM
Done dozens of swaps, its the most reliable tranny you will find.

If you have doubts about your particular transmission, contact Triple Edge Performance for a rebuild.
Dennis LaGrua FEB 16, 01:28 PM
IMO, stay with the 4T65eHD. Its compatible and strong enough to handle over 300HP reliably. Converting over to stick is a difficult process and buys you less. Remember no human can shift as fast as an 3800/automatic can in a Fiero. When tenths of a second count the automatic has it. That could make a difference between winning or losing the race.

------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

Patrick FEB 16, 03:54 PM

quote
Originally posted by Dennis LaGrua:

Remember no human can shift as fast as an 3800/automatic can in a Fiero. When tenths of a second count the automatic has it. That could make a difference between winning or losing the race.



Dennis, I read and re-read the OP's opening post, and I see no reference to him building a race car.
Never dismiss the FUN factor of driving a sporty car with a manual transmission.
Raydar FEB 16, 10:08 PM
I have done two auto-to-manual Fiero swaps. One of them is a hydraulic TOB Getrag (aka New Venture T550) bolted to a 4.9.

My opinion? For the 3800, stick with the 4T65E. It's already matched to the engine, and since the engine is a supercharged version, the trans will already have "performance aspirations".

(Conversely, the 4T60E that comes with the Caddy was designed to do nothing quickly. It's designed to move a 4000 lb Caddy down the road as smoothly as possible. The car was quick as hell with the automatic. It was just boring to drive.)

As others will certainly tell you, the gearing of most any of the manual transmissions is less than optimal for the 3800. (To be fair, it's even worse, paired with the 4.9.)
You'll blow through 1st gear in a huge hurry.

With all of that said... if you really want to row through the gears, then go for it. It's a pain in the azz to do, but it's pretty much a bolt-in. I'm quite happy with the results, even considering the non-optimal gear ratios.
Strangely enough, the hardest part is actually converting the pedals to the manual configuration. The next hardest part is getting the clutch hydraulic line up into the front compartment, where it will connect to the clutch master cylinder.

[This message has been edited by Raydar (edited 02-16-2022).]

Larryinkc FEB 16, 10:53 PM


Courtesy of the Manual Gearbox Preservation Society

https://tmgps.org/

We are the guardians of a dying art. The purveyors of a craft born of necessity, but beloved for its spirit. We travel with purpose regardless of our destination. Every corner an opportunity for the perfect downshift, every stop a new starting line. We find joy in those fleeting moments between ratios; the crescendo of rpm, the gentle click of the gate, the building inertia in our chest as the drivetrain becomes whole again. We are the masters of our machines. We are The Manual Gearbox Preservation Society!
Patrick FEB 17, 12:08 AM

quote
Originally posted by Larryinkc:

Manual Gearbox Preservation Society
MichiganReefer FEB 17, 10:15 AM
Thanks for everybody's input- especially your's Raydar. Yeah I'm not making a racecar, but I might pretend it will be on occasions. My experience so far with manual transmissions was an afternoon with one of the 6.2l Camaros last year. I've wanted to have a manual for fun and to practice more, but maybe that should be a separate vehicle. Seems for now I'll stick with the 4t65e-hd since it is the most popular opinion. Hey who knows, if it does blow up maybe I will manual swap.

For those of you who have done this swap, what was your process on making sure it's Fiero ready? I got it with the Engine from an 05 Monte Carlo SS with unknown miles and not sure if it works. Engine tear down looked uneventful, but I'm not confident in poking around the transmission myself. Have you guys just sent it as is and swaped it right on the Fiero, or have you taken it to a mechanic for them to go over and refresh? Just want to make sure I'm smart with my parts and my money.

[This message has been edited by MichiganReefer (edited 02-17-2022).]