M1009 Rear diff noise / fill plug problem

[thedeliverator]

Just last week my M1009 developed a ringing/pinging noise somewhere in the drivetrain. It sounds like something in the rear diff (or possibly the transfer case).

I checked both rear wheels, everything was fine. There's a little bit of play in the rear driveshaft - that is, I can turn it a few degrees by hand in either direction before the transfer case stops it from moving.

Since it's about that time, I figured on opening up the rear diff and having a look while changing the fluid. Therein lies the problem - someone seems to have been trying to use the wrong tool on the fill plug, and has stripped it.

What's the best way to deal with a stripped fill plug? If I drill it out, what size replacement plug will I need? If it's not in the rear diff, how hard is it to open up/work on the transfer case?

 

[acetomatoco]

take off the cover and clean it out and check on the condition in there. If it is dead... new rears complete are available cheaper than fixing a ring and pinion and a corporate locker... ACE

 

[CUCVFAN]

Check and make sure the exhaust didn't get loose and start rubbing anywhere on the t-case or support rods or the driveshaft. An exhaust rubbing the t-case or transmission will ring like crazy at certain speeds/rpms. The driveshaft will ring all of the time. You can usually see a "ring" around the driveshaft where the rust has been scraped off if this is happening. You didn't say if it was ringing all the time or not?

 

[thedeliverator]

Whoops, yeah, it only rings/pings when the wheels are moving - the exhaust is rock-solid steady, nothing to rattle around there.

It's proportional to the wheel speed, which is what makes me suspect the diff or t-case. I jacked up the rear axle and put it in drive for a bit, and it was distinctly faster than the wheel rotation - maybe three pings per turn of the wheel. Which should make sense, given that it's got a 3.56 gear ratio....

I'll try to find some way of getting the fill plug out tomorrow, open up the rear and see what's inside.

 

[CCATLETT1984]

std. gearing in the m1009's is 3.08:1

if the fill plug is stripped in the sxle cover, you could take the cover off and drill through the plug and try an easy out (bolt extractor), should come right out. If not you should be able to get a new cover fairly cheap if you just want another stock one. If you had a m1008 I could just send you my old one, since i have armored covers.

 

[thedeliverator]

Found the noise!

As it turned out, the noise wasn't in the diff itself, just close by. I pulled the driveshaft to check it, and the U-joint nearest the axle was shot. I'm suprised all it did was get noisy. The grease fitting was bent, so no lube was getting into the joint. When I pulled one of the caps off, I could see where the needle bearings had been ground into dust.

Still have a stuck fill plug on the differential, though mine isn't on the cover, it's on the side of the main housing. I picked up a reverse thread bit and an easy out bit, plan on using those tomorrow. Though it might be cheaper to take back the bit, etc (those things are expensive!), get a new cover and just tap it for a plug....

 

[steelsoldiers]

RE: Found the noise!

Oh, the one in the housing is stripped? That should be a PITA. If someone managed to strip the square hole out of the plug, they must have really been cranking on it. Just don't break the ez-out off in the plug or you will have an even bigger problem. Good luck!

 

[CUCVFAN]

RE: Found the noise!

Air chisel...