Th400 to 4L80e

[LtWood]

in my 86 gmc crew cab i have a stock 6.2 TH400 and a NP205 Tcase. i have a 4l80e out of a 97 crew cab 6.5 4wheel drive with the compushift controller. the questions i have is will the 205 Tcase bolt to the 4l80e and will the shaft engage with the adapter i have between the 400 and 205 already. please start replies with yes or no. thank u..

[Robyn]

Yes
With the proper adapter you can fit this stuff together.

The output shaft is the same diameter on the 400 and the 4L80 and the spines should be the same too.
The length of the 4L is slightly longer and you will need to do some drive line work.
Longer front line and shorter back one

T case shifter will need to be massaged a tad as will the rear crossmember to allow the assembly to fit. Likely just moving it back a little and drilling new holes in the frame flange.

Keep your driveline angle the same and things will work.

I am not exactly sure on the back bolt pattern on the 400 vs the 4L80 if they are the same but this is a minor issue.

The adapter thats with the 4L may fit onto the 205, not sure, but anything can be modified and or there is likely an adapter available.

Its GM, mix and match don't ya know. :D

Robyn

[LtWood]

i was hoping to do the conversion without buying the 600 dollar conversion kit. so i will give it a shot then see if i got to shell out the money

[mopar0096]

I'm hoping that a few people catch this and have input. This is my situation, I have a 1982 I believe not 100 percent sure of actual year. It is a regular cab flat bed truck, in absolutely cherry condition. It has a excellent running 6.2l with a 3 speed with low gear, 4.10 rearend gears. My question is, what would need to be done to get a good running high way speed out of it. I was thinking about going to the 4l80e I have heard that you can get both low and top end out of it. Since it is a 2 wheel drive, will that be all that hard to do. I am a mechanic on equipment so I have a good amount of knowledge on how to turn a wrench i'm just wondering exactly what to look for, or look out for. Also are there better ways to get some speed out of the truck? Right now its screaming at 50mph, I dont mean to hi jack the thread. I'm new and it wouldnt let me post a topic.

[DmaxMaverick]

I'm hoping that a few people catch this and have input. This is my situation, I have a 1982 I believe not 100 percent sure of actual year. It is a regular cab flat bed truck, in absolutely cherry condition. It has a excellent running 6.2l with a 3 speed with low gear, 4.10 rearend gears. My question is, what would need to be done to get a good running high way speed out of it. I was thinking about going to the 4l80e I have heard that you can get both low and top end out of it. Since it is a 2 wheel drive, will that be all that hard to do. I am a mechanic on equipment so I have a good amount of knowledge on how to turn a wrench i'm just wondering exactly what to look for, or look out for. Also are there better ways to get some speed out of the truck? Right now its screaming at 50mph, I dont mean to hi jack the thread. I'm new and it wouldnt let me post a topic.

Welcome aboard, Mopar!

You should have been able to post a new thread. Not sure about that, but I'll check into it. In the meanwhile, I'll copy your post to a new thread.

The new thread is "82 tranny upgrade? (http://www.thedieselpageforums.com/tdpforum/showthread.php?t=33984)"