'95 Jimmy 4X4 rear differential problem

[wb8yjf]

Back in May, I was stopped at a red light and when I hit the gas my 95 wouldn't move in drive OR reverse. I had it towed home and upon inspection, I found a hole (about the size of a .22) on the BACK side of the rear differential cover. I have never seen anything like this before! I surmise that the oil leaked out over a period of time and finally ran either dry or almost dry (the hole is about 1" - 1/2" from the bottom of the cover) and seized due to the excessive heat. After sitting for a couple of days, I decided to see if the rear was indeed seized. I started it up and lo & behold, it moved, albeit slowly. Before this happened, I didn't notice any 'new' noises, no grinding, etc. My question to you guys is it possible that due to the lack of lubrication it did seize due to the heat, and if I replace the cover & fill it back up, is it 'possible' that maybe, just maybe the rear end will be OK? Also, how the heck do you get this cover off? I have all but 3 bolts out, but some seem like they have weird sized heads on the bolts. Any help would be appreciated. I have a lot of money in this vehicle and would like to get it road ready before winter. I'm dying to see if there is a slug lying at the bottom of that cover.....HELP!

[jdmccright]

If it were truly a bullet hole, I'd be more worried about the damage the slug might have done to the gearing inside, or if it had jammed itself in between the cogs at the stop light.

I just replaced the diff oil in my '96 (3.73 gears), and I don't recall having too much difficulty getting the ten bolts out, though some also serve to hold down some brake line stays. But I will say that some of the heads were rusty and thus could cause your problem with finding the right size. If you can get a wire brush on them, try to scrub off the extra rust and try again. If not, try a crescent wrench. Finally, if all else fails and destructive force is necessary, go buy a set of bolt extractor sockets. They'll ruin the head and you'll need to buy new bolts, but you'll get 'em off.

My diff cover was pretty rusty, so I degreased, wire brushed it with a power drill, sprayed on some zinc primer, and painted it black with some high-temp barbecue spray paint. Haven't seen any rust since. Of course, since yours has a nice hole in it, I'd guess you'll buy a new one. Good luck!

[wb8yjf]

Yeah, I'm not sure what made that hole, but it is very suspicious. I guess I'll find out once I get that cover off. First of all I have to get the spare tire off which (as far as I can tell) has never been taken off. The lug that is holding it on is very rusted - I suspect I'll have to cut it off. Once I get the cover off, I'll post a picture of it. This is a weird one!

[jdmccright]

I didn't have to remove the spare, though it would have given me more room to move. My '96 has a crank & pulley to hold the spare. The wire rope has a crimped end that includes a stamped steel piece that fits through the spare's center hole. If you look to the right of the license plate you'll see a hole with an oblong or oval end on a pipe. That's the crank part. Stick the flat blade of the tire iron into there and crank it counterclockwise to lower the spare to the ground. If you can, it might help to shoot some rust penetrant through the spare's wheel holes up onto the pulley that sits above the spare in the middle.

Welp, I can think of three things that made the hole:

1) Something went in fast (hole edges will be bent inwards)
2) Something came out fast (hole edges would be jagged and bent outwards)
3) Corrosion ate through the steel (though that's pretty thick steel, hard to believe)

Pictures would be fantastic. Maybe a stray bullet ricocheted off the ground or something...boggles the mind.

[wb8yjf]

Yeah, that crank has NEVER been used, I've been zapping it with penetrating oil every time I walk by The hole is definitely going inward...I service bowling equipment and end up in some pretty bad neighborhoods...one place is across from some 'projects'. I'm just glad I wasn't the place where that 'thing' ended up! I'll post some pix when I get the cover off! It is a weird one! I just hope the gears didn't get all buggered up!!

THANKS for the replies!

[jdmccright]

Unless it hasn't been pulverized already and drops right out when you crack open the pumpkin, you'll have to fish the slug out of the diff with a coat hanger since it will be non-magnetic...may I suggest a kevlar-lined cover for your next purchase? Good luck.