A few suggestions:dholy said:While trying to change the gear oil in my final drive, I stripped the hex to the filler cap. In other words, the outside "hole" allowing me to insert the hex bolt into the cap. Thankfully I haven't drained the drive yet, but will ultimately need to remove this cap. Any suggestions? Thanks.
Warm the housing around the filler plug with a heat gun or carefully applied propane torch.
1) Go to the local autoparts store and get a small tube of valve lapping compound. It is a gritty paste which you can put in the stripped hex of the cap. Then place your hex wrench into the paste and jiggle and tap it 'till it gets down to the bottom. The grit may allow the wrench to engage.
2) Another option: get a socket drive Torx driver of a size just larger that the hex wrench that stripped the cap. Tap the Torx driver into the stripped cap with a small hammer.
3) Is it possible to grasp the outside of the cap with a new pair of Vice Grips? (a new one with sharp teeth in the jaws).
None of the above worked and you're getting desperate? Drill a hole through the filler plug (this will put some metal shavings inside the FD which you should flush out later). Tap an EasyOut into the hole you drilled.