GMT400 4L60e to T56 swap write up *dialup warning*

[TylerZ281500]

dont know if it will bolt to a 4.3L id do the 5.3 and t56 swap though, petty sure theres a thread or two on lstrucks or performance truck or ls1tech or something.

 

[Aloicious]

yeah, shouldn't be too different than the 5.7 T56 swap if you're usinga 5.3, you would want to use a genIII T56 for the easiest bolt up, though you might have to alter the driveshaft length a little, and adding in the clutch pedal might be a little different as well.

 

[Darkrider]

dont know if it will bolt to a 4.3L id do the 5.3 and t56 swap though, petty sure theres a thread or two on lstrucks or performance truck or ls1tech or something.

The 4.3 wouldnt be much different then the 5.7 since they share the same bellhousing but either way i will def have to look into it.

 

[GMT454]

That sounds like a decent price for a core, I wouldn't expect one to be in great usable shape for $250.

Over here people are too lazy they don't like manuals, and most of the junkyard guys don't know about these trannies potential as they don't move often they are cheap but anyways I might think in a potential overhaul/ upgrade, would it be expensive?

 

[TylerZ281500]

depends how much you get it for how complete you get it, what your gonna do to it etc. ive seen guys put next to nothing into them and people throw crazy cash into them. it all depends.

 

[GMT454]

depends how much you get it for how complete you get it, what your gonna do to it etc. ive seen guys put next to nothing into them and people throw crazy cash into them. it all depends.

just for decent performance as of now, I have a stock 454 with a Holley 600 CFM carb on it so it is not a killer... yet

 

[Aloicious]

depends how much you get it for how complete you get it, what your gonna do to it etc. ive seen guys put next to nothing into them and people throw crazy cash into them. it all depends.

+1

it kindof depends on what it needs, if the main gears/parts are good, then it shouldn't be too hard or costly to soup it up a little. if you need to start replacing primary gears or shafts, then it can get pretty costly fast.

 

[SixSpeedSS]

The 4.3 wouldnt be much different then the 5.7 since they share the same bellhousing but either way i will def have to look into it.

IIRC the 4.3 still has a flange on the back of the block like any old small/big block. The LS motors do not have this flange. The bolt pattern is the same, but the trans input shaft length is very different.

I would think you need 5.13 gears at least to run the T56 in 6th gear behind the 4.3L. With 50% overdrive in 6th gear, you need a motor with a lot of low end torque.

 

[TylerZ281500]

theres a great writeup on t56s on thirdgen.org IIRC

 

[jollyjerry]

Sorry to bump an old thread, but in case the images go down, I made an archive of this thread in http://www.wikiwrench.com/index.php/4L60E_to_T56_Transmission_Swap

Some of the links near the bottom of the post are dead already, but I found a few replacement sources and added those back in. That article could probably use a refresher if anyone does decide to tackle the swap. Feel free to edit it as needed.