Swap a TH350 for a 4L60E?

[Matt Cramer]

Been contemplating this for my truck (1972 C10 with a 2-piece driveshaft). I'm aware of the driveshaft probably needing to be shortened (looks like I've got a 6" tailshaft on the TH350, but I haven't measured it to make sure) and plan to use a MegaShift for the electronics, but have a couple unanswered questions.

1. Would my existing shift linkage connect up, or did 4L60E equipped cars put the shift switchgear outside the transmission?

2. Any changes needed to the rear trans mount or crossmember?

3. Anything else needed, like hammering on the floorboards to get it to clear?

Not sure if I'll go through with this, but thought I'd poke around to see how much work I'd be getting myself into if I tried.

[squirrel]

should have a long tailshaft trans in there if it's original. That makes it easy, since it should bethe same length as the 4L60E.

You'd need to move the crossmember back a bit so the mount lines up. That involves drilling 8 each 3/8" holes in the frame, which is a bitch. Unless it happens to have holes already in the right place to work with the TH400? Take a look.

The rest of it should work pretty well, same linkage in the same place, you won't get manual 1st gear unless you play with the shifter gate so the lever can move further, I think.

And the usual stuff about playing with wiring and computers, but you know all about that. Your speedo won't work, but I expect you have a digital solution for that.

[anotheridiot]

what I know is the 4L60 replicates the 350 and the 4L80 replicates the turbo 400. Most of the internals are the same, so the externals probably are too.

[squirrel]

The externals are similar, but the length and weight are different, and the mount is in a different place.

[Deaf Bob]

So the 4L60&80 are electronic speedo units?
Can they run without electronics? If not what are they set off of?

[squirrel]

The E suffix transmissions are Electronic control. The 4L60 is a 700R4. The 4L60E is a computer controlled transmission.

The 4L80E is computer controlled, there is no non-computer version of it unfortunately.