GM automagic trans interchange or upgrades

[Scott Cee AKA 2drx4]

I've got a 04 GM 5.3L that was out of a 1500 automatic truck, so I'm guessing it had the 4L60E behind it. Those aren't known to be reliable behind even the power of a 5.3L, hence the trans was already sold when I went to get the engine. I have the whole engine/trans wiring harness and ECM, etc from the truck.

Can I just bolt in a 4L80E and have it work with the wiring? Or is it worthwhile to find a core 4L60E or 4L65E and rebuild with some upgraded parts?

If I go with the 4L60E are they the 6 bolt NP/NV tcase pattern? I know some of the early stuff was a stupid 5 bolt pattern. I have a couple earlier NP/NV241s with the GM input gear in them, and I would use one of them for an Ecobox donor, so the Ecobox preferably needs to bolt up without an adapter.


This is longer term planning stuff. I just need to know what I can use so I can pick it up when I see the right deal.

[pointsnorth]

ive never seen a 4L60E that wasnt a six bolt pattern. but im pretty sure ive also never pulled either the early 4l60 or 4l80 series that were installed behind the vortec 350 or 454 from the early 90s. i know the hotrodders and street guys always have a hardon for them as they had a stand alone tcm that was super simple to put behind any sbc or bbc. id say as long as it was behind a ls motor your safe.

[Scott Cee AKA 2drx4]

Okay, good to know they went away from that 5 bolt trash. That opens it up to basically being anything after 2000~.

I'll have to look into if the electrical connectors are the same between the 4L60E and the 4L80E.

[Johnny5]

I dunno if that’s whatcha lookin for but I believe my old man has my old 4l60e from a 97 350 vortec. Prob wouldn’t want much for it but I can’t remember if I pulled the tcm with it or not. Also if it doesn’t work cause it’s too old that’s no good either

[Scott Cee AKA 2drx4]

I dunno if that’s whatcha lookin for but I believe my old man has my old 4l60e from a 97 350 vortec. Prob wouldn’t want much for it but I can’t remember if I pulled the tcm with it or not. Also if it doesn’t work cause it’s too old that’s no good either

Too old I think.

[Scott Cee AKA 2drx4]

I found a low km 99-03 4L80E for a decent price. I think it should work but will need to look into the electrical connectors some more.

[Scott Cee AKA 2drx4]

I guess there might be issues with the torque converter or flexplate because of the weird different GM crank flange stickout lengths. I forget how that all works, but I believe my 5.3 (out of an 04) has the same crank flange stickout as a 6.0L.


And the wiring harness uses different plugs.

[pointsnorth]

i think you can still swap the prndl switch on the side of the trans for the one that has the right plugs with out issue

[Scott Cee AKA 2drx4]

i think you can still swap the prndl switch on the side of the trans for the one that has the right plugs with out issue

That would possibly be an easy fix then.

[Scott Cee AKA 2drx4]

Looks like I need a flexplate and a spacer.

Or a flexplate with the spacer built in:
https://www.rockauto.com/en/moreinfo.ph ... me3A%3D%3D

[Scott Cee AKA 2drx4]

Turns out that tranny had a piece of the bellhousing busted off. You know, one of those details you probably should mention when a potential buyer asks if there's a anything wrong with it.

[HMF]

Turns out that tranny had a piece of the bellhousing busted off. You know, one of those details you probably should mention when a potential buyer asks if there's a anything wrong with it.

But you can fix that. As long as its only just like 1 tab haha

[Scott Cee AKA 2drx4]

Turns out that tranny had a piece of the bellhousing busted off. You know, one of those details you probably should mention when a potential buyer asks if there's a anything wrong with it.

But you can fix that. As long as its only just like 1 tab haha

Maybe if he included the piece that was broken off.

[Scott Cee AKA 2drx4]

What about the 4L65? Worth bothering with? Or just go 4L80?

[pointsnorth]

Hard to Identify unless you have the rpo codes or a tear down.


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