New here, but I see a fair bit of knowledge on here with the 4l80e transmissions. I'm new to autos, but I've had a few power shift trans apart, so not new in general.
First thing is, the only thing that has failed in the forward clutch. I want to figure out why. It may just be miles though. (233k miles) Not big power, but don't want it failing again.

Anything obvious to look at? Teflon rings would be the most obvious, but I don't see much as far as that goes. (I'm going to replace them though) I have read about end play causing issues? Also wondering about adding another friction? I've read some guys get rid of the wave plate, add an extra .060 steel and extra friction. Is that correct? Any downsides to doing this? I know there is a kit out there for 7 frictions, but not crazy about everything being that thin.
Other thing is, I have the pump apart, and I am not crazy about the clearances I'm seeing. The internal gear looks good. Seems to be decently tight to the crescent and pump housing. The drive gear is what I'm concerned about. I haven't measured any clearances yet, but I'd guess there's 0.008" clearance in there, when the drive gear is pressed tight against the internal gear. Does anybody have specs on what the clearances are supposed to be, as well as what the OD of the drive gear is supposed to be? I don't have anything for a manual yet, being in Canada, it has proven difficult to find an ATSG rebuild manual that will ship to Canada. Thanks for reading.

 

Check for sealing ring wear in the drum.
End play can cause issues as you've stated.
5 frictions will hold 1000hp. Don't bother with 7. Just run 5 HE borgs in there.
Check manual valve wear and adjustment