80 series tranny questions

[jkl72-40]

My son has the 97 lx450 at collage and says the tranny is slipping and Im trying to figure things out long distance(fun...not).
During the -2 temps the fluid level looked low(he added fluid during this time,) but when he left it was spot on and never leaked,
now that it has warmed up its showing overfull, he has stated its started slipping is this due to the over full or is it going bad? When these tranny's go what are the common issues? Truck still is drivable tho and acts up once in a while. Or if he can get it to SLEE I can take it there.
Any thoughts?
Kyle

 

[pedwards]

I would suggest draining out some of the extra fluid and see if that fixes everything. These transmissions are usually very robust.

cleanest way might be to disconnect a hose at the transmission cooler input and drain into a 5 gallon bucket as the truck idles.

 

[jkl72-40]

I would suggest draining out some of the extra fluid and see if that fixes everything. These transmissions are usually very robust.

cleanest way might be to disconnect a hose at the transmission cooler input and drain into a 5 gallon bucket as the truck idles.

Thanks!!