Hi everybody, 2002 Chevy Trailblazer 4WD.
I pulled my rear differential cover off to change the gear lube in it. It was leaking out of the gasket.
However I can't get the fill plug out. I've tried an impact wrench, heat, PB Blaster and a pipe on my ratchet. not in that particular order. no dice! Any ideas? could I drill it out and tap it with new threads?
Thanks!

If you didn't have the pan off already, I'd suggest getting something almost as big around as the plug, like a socket. Get under there every day or two and put it between the plug and your hammer and give it a couple of good whacks. Twist, and if it doesn't turn, give up for the day and repeat the same procedure again after you've driven it some more. It'* probably just never been taken out.

We recently had another member with the same issue on the same platform: https://www.gmforum.com/gmc-chevrole...-light-314442/

They ended up buying a differential cover with a fill plug built in.

Otherwise yes you can get more destructive. If you have experience with such things then you'll come out okay. If not then maybe not. I'd guess that a few cycles of heat and cold while there is a twisting force being applied would break it loose. Try this:

- Breaker bar and extension rotated to the right angle
- Hook a ratchet strap to the end of the breaker bar, with the other end somewhere solid like in a frame hole
- Tighten the strap as much as you dare
- Heat cold heat cold heat cold heat cold heat cold

Hopefully that would do the trick.

We'd love to hear what you do to get it figured out!

thanks CathedralCub. I will sure let you all know what I come up with.

I read that thread not to long ago and actually forgot I had read it. I'm doing to much at once, trying to get it ready for winter. HVAC no heat, wipers doing funky stuff, new radio and speakers, tune up, valve cover gasket, belt and tensioner, brakes!! Yea I'm a bit scatter brained right now. and still haven't got my EVAP leak fixed. I found a leak and repaired that one but it says I still have a leak somewhere. Maybe if I bang my head against the concrete driveway I'll clear the cobwebs! LOL.
Just bought a cool new scan tool. Hope I can fix HVAC and EVAP problems with it.
I'll keep you posted.

Well I got it out! I did what you said CathedralCub. heated it up with a torch and then sprayed cold water on it. then beat on it a little with a hammer and tool. repeated it 2 more times then put my 1/2 inch drive ratchet on it with an adapter down to 3/8 inch and about a 2 foot pipe on the ratchet. It took quite a bit of strength on that pipe but all of a sudden it just snapped free!
Thanks for the help, appreciate it!

by the way, just FYI, I put the heat right on the fill plug only. Don't know if that matters.

Thanks for letting us know how it came out!