03sierraslt

iTrader: (22)

Change the input shaft, no adapter needed.

alex226

Really? I dont need the adapter at all? Would you only need that if you had a 2WD 4L80e? Is it basically a new tail housing?

George C....

have you considered a 6l80?

alex226

I have, but havent researched the difference compared to the 4 speed swap..

This is just my dd... I really cannot have it be down long. Can all the normal 4 speed conversion stuff still be used? I know the cooling lines are different, but that's all I know.

Edit: found a build thread for the 6speed....looked to be considerably more work. Especially with with the difference in computer systems needed.

alex226

Does this look right? I want to purchase today!

For the converter, I'm going with a circle d for a 4L80e. Its the stock 310mm unit that has been opened up and "has a billet lockup piston and a billet front cover. It also has a larger lockup clutch that may accept WOT lockup." I think I'm going to do this over their budget converter that bolts up to the stock 60e plate. Do I need any special 80e plate for this to work?

Can someone please confirm the list above is only missing the driveshafts shortened /lengthened to be complete (tune of course too)?

GM1697

iTrader: (1)

I'm pretty sure you don't need a wiring harness, just have to re-pin your stock one.

alex226

I ordered everything above. I'm about 99% sure that's all it needed. Frosts harness guarantees lockup even off throttle so I just bought it. If it saves me a few hours and frustration it's worth it. Here's the trans I'm eyeing up. Older fella has it sitting in his garage since 02. Got it rebuilt to put in his truck but sold the truck before he did it.


It doesn't have the top bolt but from what I'm reading that shouldn't be an issue? It seems to have the bolt holes for the neutral switch. So that's the major concern right?

GMCtrk

iTrader: (27)

You're good to go.

My trans is from a 97 I believe (No top bolt). I only use 2 bolts on each side of the dowel anyways (4 total).

alex226

Good deal. Thanks guys. I'll try to snag that transmission this week before it gets sold!

Now onto more decisions, I should regear (currently 3.73's)

The truck was really close to being able to hold 4th with the turbo. I've read multiple times 3.73 --> 4.10's is a waste of money. So got me thinking maybe some motive 4.30's? I see people suggesting 4.56's for 35's, but most were running N/A motors.

I will probably wait, see what this circle d converter and different gearing is going to do in the 80e. How many rpm difference is the OD (.75 vs .70) in the 80 vs 60e @ ~70mph?

GRRR65GTO

Well if you go on the highway alot i dont know if you want to go higher than 4:10s. I have 4:10s with 33s and at 70 im a little over 2000 but if I go like 80 im at 2500. And if I cruise at like 50-55 my gas mileage goes way up compared to normal highway speeds, and thats when its at like 1600-1700

4:56s might make it rape on the street but she'll be screamin on the highway