I bought a used 4L80E transmission with 120K miles (I was told). Didn't see it run. The guy swaped a 4WD transmission in his 2wd truck.
Anyways, I'd like to get an aftermarket torque converter for it.
Before I do this I'd like to know what can I inspect before I install it in the car to make sure nothing is wrong with it. I don't want to pay close to a 1000 dollars on a TC that would get damaged if the transmission blows not long after.

So I opened the pan, it looks clean inside, oils is dark red, brownish. The gasket had black and orange gasket maker on it so I guess it was opened a couple of times, hopefully just for maintenance (fluid and filter change). It did not have much fluid but it's missing the dipstick as well as the tube so I guess much of it was drained through the dipstick hole.

I'll install a drain plug and a new filter but since I am in there what else should I do? Change the plate and the ***** with torlon check *****?
Anything else?
I don't want to spend more money than necessary besides basic maintenance if nothing else needs attention. It will be behind a very mildly cammed LQ4.

 

It's really a shot in the dark without opening it up. Probably do some sonnax parts in the valve body and a booster kit in the pump and see what it does. I went through the same thing and it didn't work out for me. I'm now into mine way more than I was originally expecting.

 

That sucks, sorry to hear it didn't work for you. Did you look in the pan before installing it? Mine doesn't seem bad, a bit of material on the magnet but I would say it looks like normal wear. I didn't want to start throwing parts at it since the engine I have shouldn't have a lot more power than stock. The thing is thjat if I had a lift I wouldn't mind installing it as is and see how it works out. But I don't, I got to lift the car to install the transmission and put it on some old wheels I have to get enough clearance to slide under. And then lift it with a motorcycle jack. Big PITA.

 

I did my swap with a $99 harbor freight trans jack with the truck on jack stands as well.

As far as trusting a VERY used 4l80e, you need to balance out a rebuild vs time and $$ if you don't and it needs a rebuild or leaves you stranded. I'm glad I went through mine. You can easily do all clutches, bushings where needed and the internal dual feed mod for fairly cheap.

Wittrans.com is a place you can piece together your own rebuild kit depending on what you find.

I know first hand here that there are a ton of people that can help you along the way. See my 4l80e thread for example!! I don't know much, but have been guided along the way thankfully.

 

It's normal to have some material in the pan. My trans had a pretty rare situation where the bushing in the center support was installed incorrectly by whoever had it before not allowing fluid from the cooler lines to return into the case. With your situation I think you should be safe just doing a shift kit and installing the trans. But, it is still taking a risk.

 

Never tore deep in a transmission, just opened up my old 4L60E and improved some stuff in the valve body. I am not afraid of the rebuild, mainly a budget thing. I'll check out the cost of parts and finish reading the rebuild manual. For sure the smart thing is to rebuild the transmission, and engine which I also bought used. Anyways it's a project car, not my main one.

Maybe I'll wait one more year for my converter then and invest the money in rebuilding the transmission.

Thanks for your replies.