3800 Series II L36 + 4 speed manual? (Page 1/2)
AsaBergman SEP 10, 08:26 AM
First if your response if "search the forums" don't reply. Thank you and God bless.

The swap I have in mind is a 3800 Series II naturally aspirated plus a 4 speed 4.10 transmission. Strictly a daily driver. Question is will the 4.10 transmission survive just normal calm daily driving with a L36? No clutch dumps, no drag strip, none of that.

Second question. Will all the internals from a 4.10 fit into the v6 case? I have all the tools required to rebuild a 4 speed already.
olejoedad SEP 10, 10:06 AM
No, it won't hold up.
Yes, the parts will interchange.
Additionally....
The shift cables on the four speed will need to be rerouted to clear the 3800 exhaust.
The 4.10 ratio is a terrible choice for the 3800.
AsaBergman SEP 10, 12:15 PM

quote
Originally posted by olejoedad:

No, it won't hold up.
Yes, the parts will interchange.
Additionally....
The shift cables on the four speed will need to be rerouted to clear the 3800 exhaust.
The 4.10 ratio is a terrible choice for the 3800.



Unfortunate that it won't hold up. I also have an MY8 but I'll assume that also won't hold up either. Will have to look into an F23 or F40.
I'll have to respectfully disagree on the ratio being a terrible choice. Most people doing a 3800 swap in a Fiero have different goals. I have another car running an L67 with a 4.08 diff ratio and it works very well for me.
Thanks for the response.
pmbrunelle SEP 10, 12:18 PM

quote
Originally posted by AsaBergman:
Second question. Will all the internals from a 4.10 fit into the v6 case? I have all the tools required to rebuild a 4 speed already.



Yes, but where "internals" refers to the three shafts (input, output, and differential), and some other hardware (shift interlock mechanism, reverse idler, and others).

Off the top of my head, the shift forks from the V6 must be used with the V6 case. The 4-cylinder shift forks are not compatible with the V6 case.

I did the 1984 Performance gearing swap into my V6 Muncie for my Fiero project car.

For you, you may want to consider doing a mix-and-match, such as using the V6 1st/2nd gears rather than the 1984 gearing in its entirety.

Making a new crossover pipe for the 3800 seems easier to me than messing with the shift cables.

[This message has been edited by pmbrunelle (edited 09-10-2019).]

pmbrunelle SEP 10, 12:24 PM
Joe, when you say the 4.10 stuff won't hold up, do you mean the 4.10 transmission assembly as built by GM (smooth case), or the 4.10 gearing in the V6 ribbed case?
olejoedad SEP 10, 01:55 PM
The smooth case will not hold up.

I can't speak to the internal shafts with the 4.10 ratio.
Dave E Bouy SEP 10, 07:54 PM
I would certainly go for it with the MY8! There's never a shortage of nay sayers. I had this transmission behind a Series II supercharged motor and it held up to a fair amount of abuse. The rerouting of the 4spd cables was incredibly easy.

DF
larafan SEP 11, 12:10 AM
I have a hybrid 4 spd built from an 86 M17 4 spd and an MY8 behind my L67 in my 84. In the stronger case it has been superb. The gearing combination makes it a great city driver as well as 4th gear being a nice overdrive at 70mph. 2 years and about 13k since swap and driven regularly. No, I don't abuse it. I built it to keep it but I know what it can do. Always loved a 4 spd.
AsaBergman SEP 11, 09:45 AM
Sorry for the delay. I know the smooth case is a weak point which is why I plan on using the ribbed case.

pmbrunelle, thanks for the info. I knew about the 1/2 gears being swapped but the main post I found regarding this was for 3.32, was unsure if 4.10 gears would work. The v6 1st gear would actually help my only complaint with the 4.10: the 1 to 2 shift drops too low. I did not know some of the non-gear internals are different, I'll have to locate a known working v6 trans then to ensure I have everything in good order.

Dave, if it held up to your supercharged I think it'll hold up to a naturally aspirated engine that I'm going to drive like a granny. Haha.

larafan, that's the kind of info I wanted. 13k miles behind a stronger engine without it blowing up is more than acceptable to me.

I'm going to track down a healthy v6 trans and go for it. I already have a series II 3800 long block in the garage to begin mocking up a swap. I'll have to look at the numbers ( gafiero's calculator is great for this ) and figure out which differential I'll use since I'll have all three available. Still leaning towards 4.10 since it's all hills and mountains here and I like where it puts the rpms, rarely need to downshift and never have to floor it. Maybe I'll post the 3.32 diff on here if I don't use it, not sure if there's still any demand for them.
Dennis LaGrua SEP 14, 10:26 AM
Many engine swaps have been done with the 4 speed Muncie and 5 Speed Getrag but the manufacturing parameters are that these small transmissions were designed to operate with a maximum of 180-200 ft lbs of torque. With the L36 3800 Series III N/A you will be putting 230 ft lbs of torque into an old well used transmission. As long as you don't drive with a heavy foot, the trans might hold up but the stock clutch may not. In addition the 4:10 FDR isn't the best choice for drivability and economy. You'd be far better off if you used the 4T65e transmission that GM designed to work with these engines.

------------------
" 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 "