4L80e swap question

So we are idiots…a few neighbors and I decided we could swap a 4L80 out of my neighbor’s work truck.

We thought we could do this last Sunday in a few hours with a few beers but it turned out to be more work than expected.

The first major problem was that the motor and tranny seemed welded together by the guide pins. After a long time forcing it in every possible way we decided to take a break until we could heat it properly with a torch. That part was done yesterday and they managed to take it off.

We thought the tranny would come out without taking off the exhaust but even in the best possible angle it still wouldn’t clear the exhaust. The part we needed to remove is the one that came down from the manifold, at almost 300 000km that and the O2 sensor we tried to remove were really rusty. We decided on cutting the exhaust and welding later on since one of us can weld pretty good

Now tonight we tried to get the new tranny in and it just doesn’t want to go in, the torque converter hits the flexplate before the edge of the tranny housing sits against the motor. So I was wondering, is it possible to install the torque converter on the motor before we install the transmission?

Not a good solution, measure and make surenyou have the same transmission!


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Ça ressemble à toute les fois que j'ai entrepris une modification sur un char. Aucune surprise ici.

Not a good forum for that sort of question... on 14 active forum members i'd say maybe 1 or 2 ever swapped an engine before.

Je te dirais d'aller au concessionnaire

Plus le choix de faire la job à ce point ci. La transmission est maintenant en place, il reste à remonter tout le reste.

You have to seat the torque converter before you install the transmission. Make sure to try to keep the torque matching the trans. Also flush out the lines if possible or add a trans cooler seperate. Because if the old transmission blew chunks of material it's a bad idea to reintroduce it. Or flush it properly after.

It’s definitely getting a full flush. Anyways most of it leaked out lol

heat dowel with torch next time, this helps a lot. 4l60 and 4l80 have different flexplates. you will also need to modify harness and transmission file in the ecu. you can install tranny with converter either way but usuay much easier with the converter in the transmission. make shure your converter is properly seated before torqing engine to tranny bolts.have you changed input seal? they usually leaks right after swaping like you did...lol

Didn’t change any seals lol

RWDLover1 said:

So we are idiots…a few neighbors and I decided we could swap a 4L80 out of my neighbor’s work truck.

We thought we could do this last Sunday in a few hours with a few beers but it turned out to be more work than expected.

The first major problem was that the motor and tranny seemed welded together by the guide pins. After a long time forcing it in every possible way we decided to take a break until we could heat it properly with a torch. That part was done yesterday and they managed to take it off.

We thought the tranny would come out without taking off the exhaust but even in the best possible angle it still wouldn’t clear the exhaust. The part we needed to remove is the one that came down from the manifold, at almost 300 000km that and the O2 sensor we tried to remove were really rusty. We decided on cutting the exhaust and welding later on since one of us can weld pretty good

Now tonight we tried to get the new tranny in and it just doesn’t want to go in, the torque converter hits the flexplate before the edge of the tranny housing sits against the motor. So I was wondering, is it possible to install the torque converter on the motor before we install the transmission?

Click to expand...

Killingcivics said:

You have to seat the torque converter before you install the transmission. Make sure to try to keep the torque matching the trans. Also flush out the lines if possible or add a trans cooler seperate. Because if the old transmission blew chunks of material it's a bad idea to reintroduce it. Or flush it properly after.

Click to expand...

This

Update: truck runs, tranny felt lazy at first but after feeding it more oil and driving it a little more it’s feeling much better.

Still have to fix 2-3 bugs like no more reverse lights but at least it runs now.