4l80e Overdrive planetary thrust bearing failure
 

My 2003 completely stock 4l80e quit making line pressure and I noticed it starting to slip in 2nd gear and the TCC slips when locking. When I tore into it I found that the overdrive planetary and the forward clutch assembly was damaged due to what apprears to be a thrust bearing failure. But I am not sure what caused this to happen maybe a lubrication problem or possibly a bad bearing due to rust since the transmission sat a long time before being used. Just want to do all I can do to prevent it from reoccurring. I am wanting to build this transmission to hold big power so I have recently ordered a stage 5 kit from Jakes Performance, plan to rollerize the rear case, run a triple disc converter and run tight end clearances. From what I have read the input shaft splines on the overdrive planetary is not a common failure but since mine is damaged I am thinking about going with a TCS or PATC overdrive planet with a hardened input billet spline hub. This is my first 4l80e build and I feel I have gained a lot of knowledge from forums like this one. Any tips or ideas that caused this issue are greatly appreciated!

Re: 4l80e Overdrive planetary thrust bearing failure
 

Are you finding rust on some of the hard parts as you disassemble this 4L80. If you are I suggest you replace all Torrington bearings in this unit. Rust is not a good thing to have in any trans. It will make a Torrington bearing come apart in a hurry. Also if you find excessive rust in this unit I would look for another core to build. Any rust found in any of the planetaries would be tossed
Away and not used if it was mine. Good luck !!!!

Re: 4l80e Overdrive planetary thrust bearing failure
 

Thanks Youngpup1977 It did have a little rust on the foward drum housing. But everything else hasn't been bad. I have an idea about how rust can destroy a bearing just a small pit can make a roller bearing howl. The more I think about it I really think this was a result of a clogged lubrication port. The reason I say that is I was really hard on it before it quit. While being hard on it the converter lockup was a lot slower to apply like it was sliping and second gear slipped when powerbrakeing it. After that I was easy on trying not to hurt it any more but it ended up loosing line pressure and I found excessive metal in the pan. I still have a few more clutch packs to look at but I really think all the slipping could have clogged the lube port to this area and caused the failure.

On the overdrive planet in 1997 and later they went to the 4 slot oiling instead of the two slot. Most of the time these do not clog up but were upgraded to from 2 to 4 slot to improve the oil volume. The pic shows the difference.
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Re: 4l80e Overdrive planetary thrust bearing failure
 

I consider any planetary or bearing failure as a lubrication failure. Pay close attention to the cooler circuit.

I have a 4L60e on the bench now that has obviously been in water more than once. (lots of flooding around here the last couple years). Pretty heavy scale rust on many of the hard parts. Ultimately though, the failure was due to clutch delamination due to the water.

Re: 4l80e Overdrive planetary thrust bearing failure
 

Thanks guys, definitely don't want a repeat of this. Interesting how GM removed 2 extra teeth to help with lubrication. I am also hoping that the splines hold up to the torque and 300m input shaft. I ordered a used OD planetary and a new gm foward clutch hub on ebay.
I tore into the pump, not to bad looking and about. 001 above max tolerance on the gear height. Hopefully a new gear set will fix this issue. Having trouble finding a good quality pump gear set, a lot of no name stuff I don't trust. Maybe Monday I'll find a good set preferably ac delco, I guess sonnax pump gears are okay as well. Where do yall purchase your tranny parts usually?

Re: 4l80e Overdrive planetary thrust bearing failure
 

Judging by the rust on the foward hub a rusted roller bearing is a probably the most likely cause.