Differential Fill Plug . . .

pwsigmund · October 5, 2009

Project to replace the rusted out rear brake backing plates on my 02 Yukon hasn't started off too well. Has anyone experienced problems cracking loose the differential fill plug? I'm soaking it overnight in Kroil, but it wouldn't budge, even after wire brushing all of the rust off the outside. Kind of hate to take a torch under there considering the nearby gas tank and all. Haven't tried the drain plug yet.

Any suggestions or experiences would be appreciated!

txab · October 5, 2009

The gas tank isn't that close. Heating it is one of the ways to get it off. If you got a torch I'd use it. Don't remove the drain plug or cover until you get the fill plug out

gmtech4 · October 5, 2009

I disagree with txab,please do not do that ,if you have air and an air chisel ,get a flat bit for it and bark out the plug by digging in the edge and go lefty loosey ,comes out every time,

pwsigmund · October 6, 2009

I disagree with txab,please do not do that ,if you have air and an air chisel ,get a flat bit for it and bark out the plug by digging in the edge and go lefty loosey ,comes out every time,

Thanks. I'll try that first, as I really don't feel realy comfortable underneath with a torch.

If all else fails, is there such a thing as an aftermarket cover with a fill port in it? I've got a drain plug on the bottom.

Matt_ · October 6, 2009

Check out the TA differential covers, they have drain/fill ports.

How long is the ratchet you're trying to use? Leverage is your friend

jrod332 · October 6, 2009

Check out the TA differential covers, they have drain/fill ports.

How long is the ratchet you're trying to use? Leverage is your friend

Put a pipe over the ratchet. as sk1er18 said leverage is amazing. Try some pb blaster on it.

WilliamBos · October 6, 2009

Check out the TA differential covers, they have drain/fill ports.

How long is the ratchet you're trying to use? Leverage is your friend

Would you have a link??

Matt_ · October 6, 2009

http://www.ronsmachiningservice.com/store/...=418&page=1

gmtech4 · October 6, 2009

price out a factory cover out also as it may be cheaper than aftermarket bling(not required under a truck)

pwsigmund · October 6, 2009

I let Kroil (great penetrating oil) work on it overnight. I'll give a 1/2 breaker bar a try tomorrow with slow pressure. I initially tried a 1/2 impact gun reduced to 3/8, and the extension started to slip in the plug's socket, which worried me. I hope it will break free before the plug deforms. Maybe I should sacrifice a 3/8 extension and grind the end flat to get as much "bite" as possible. If it deforms before it breaks, then I'm stuck. . . .

dlstewart01 · October 6, 2009

Mag-Hytec diff covers have a drain and fill plug and a dip-stick.

WilliamBos · October 6, 2009

Mag-Hytec diff covers have a drain and fill plug and a dip-stick.

What holds the stick in??

dlstewart01 · October 7, 2009

The fill hole is threaded and the dip stick screws in. It has an o-ring to seal it, The dip stick also contains a magnet to catch steel particles.

http://www.mag-hytec.com/store/index.php?m...031efbaf03241bd

pwsigmund · October 7, 2009

I was able to get the plug out with a 18 inch breaker bar. The fill plug socket was so worn that the 3/8 extension's points were all that was diggin into the plug's socket flats. Not much more left to grab. But it was just enough to break it loose. When that plug finally started turning it was a great feeling!

Oil was black, and really seemed thinner than 75/90 weight. I guess it breaks down after 130K. Lot's of metallic shiny looking glop in the bottom and on the inner cover. Guess I should rinse some kerosene around in there. Took a lot of wire wheelin to get all of that thick rust layer off of the cover. What a mess.

All of the cover bolts had what looked like Loktite on the threads. Should I use thread sealant again after I clean them up, or just add some lock washers?

Any tips on getting the large pin out of the carrier, to free the axles?

Thanks for all of your help

txab · October 7, 2009

I was able to get the plug out with a 18 inch breaker bar. The fill plug socket was so worn that the 3/8 extension's points were all that was diggin into the plug's socket flats. Not much more left to grab. But it was just enough to break it loose. When that plug finally started turning it was a great feeling!

Oil was black, and really seemed thinner than 75/90 weight. I guess it breaks down after 130K. Lot's of metallic shiny looking glop in the bottom and on the inner cover. Guess I should rinse some kerosene around in there. Took a lot of wire wheelin to get all of that thick rust layer off of the cover. What a mess.

All of the cover bolts had what looked like Loktite on the threads. Should I use thread sealant again after I clean them up, or just add some lock washers?

Any tips on getting the large pin out of the carrier, to free the axles?

Thanks for all of your help

Check this thread for some help.