Agh.....rear diff seized.....I think

[Numbchux]

Driving home from work tonight, and something stopped spinning. I was driving about 60mph, and something locked. it was dark and raining, so no skidmarks to check. But, I felt no pull in the steering wheel, and the car started to drift sideways as it skidded, but I was able to countersteer and keep it pretty straight-ish. so I suspect both rears were locked and both fronts were spinning.

 

once the car came to a stop, I was able to get it to drive backwards a foot or so, and then it would drive forward to get it out of the road. I made it about 20 feet down the road on the shoulder then before it seized again, at which point, I wouldn't move at all.

 

Assuming my assumption was correct (let me know if you see any holes in the theory), the center diff was working correctly. Wheel bearing seems really unlikely, as it would lock just one wheel, which I don't think was the case. ditto: axle.

 

Only things behind the center diff, that would still effect both rear wheels, are the transfer gears in the transmission, and rear diff itself. I pulled the transmission dipstick and in the light in the car, didn't see any metal flakes or anything. So I'm suspecting rear diff. Thoughts? My girlfriend is going to give me a ride out to it with my spare 4.111 rear diff in the morning, but she can't hang out to see if I'm successful. So I want to run these ideas by someone else.....

 

 

Setup is: 1988 XT6. stock engine, and transmission case halves. '94 impreza shafts, gears, synchros, center diff, front diff, and center diff case. '94 legacy rear diff case/gears with an RX LSD rear diff in it.

[nipper]

I am not too familiar with this, but ill give it a shot.

 

Usually rear diffs dont just seize. They die a long noisy death. They will develop a whine that get slouder with speed, then one day the gears will just strip.

 

Now if it is a mechanical LSD, then yes it is possible it threw something. mechanical LSDs can seize, but it is very rare. The first thing I would try is to disconnect the driveshaft and see if the car will move (by pushing since this is manual). There aretwo possible scenarios here, and one is ugly. A wheel bearing wont seize, but would really develop alot of play and alot of noise and poor tracking.

 

Also another weirdness (very long shot) check to make sure the brakes didnt lock up for some wierd reason.

 

nipper

[s'ko]

i think that nipper has a point with the mechanical lsd having something get caught in the gears

might have been one of the bolts holding the ring onto the diff

since you are planning to pull the diff

maybe your girl can wait until you pull the drivershaft

if it moves with that removed then you should b good 2 go with the new diff installed. (added for clarification)

 

good luck

bw

Edited March 11, 2010 by s'ko

[WoodsWagon]

He has an impreza center diff, so no moving with no driveshaft. I've killed a few diffs in my time, and when something gets caught between the ring and pinion, it all stops fast. Popping it in reverse and going backwards can sometimes get the offending piece to drop out and you can continue on your way, but the piece can get wedged and you're SOL.

 

Had this happen on a woods beater ford truck. One of the welds on the spider gears had popped, and the clump of weld/bolt got caught in the R&P. Truck locked up solid. We were illegaly road ripping at that point, so I grabbed reverse, rocked it a couple times, it popped loose and we were on our way.

 

One open subaru diff I had to keep loaded the whole way home with the handbrake. I was running RWD and the spider gears let go. I almost made it, but I let off on brake on the last hill and it all went to hell. Carrier broke on that one. 4.5 miles on a thouroughly grenaded diff is no joke, but it got me away from the scene of the crime. Same thing happened to the front diff of one of my D/R 5spds. It got loud if it wasn't loaded, and came apart between gears when I was shifting. Blew a piece out of the bottom of the case, but there were enough gear nubbins left that I limped it home leaving a trail of shame. I was only 15mins late to work because of that one.

[nipper]

He has an impreza center diff, so no moving with no driveshaft.

 

 

yup thats why i said try to push it, It will tell you right away with the drive shaft disconnected if the rear is locked up.

 

nipper

[Numbchux]

Well....problem. the impreza diff I have here on the shelf is different. can't put stubs in it. splines inside the diff are different.

 

I have another carrier here, that does work with the stubs, but the impreza has thread-in bearing retainers on the sides of the case, that I can't remove (which is why I got my hands on that legacy one that's in it).

 

 

So....thoughts? I think I'm down to pulling the rear axles and driveshaft and dragging it home on a strap.

[s'ko]

Chuks.

Sounds like you are in a jam.

Removing the rear diff will let you pull the car.

How far do you have to go?

Can you get AAA to tow you home?

Hope things work out.

BW

[Numbchux]

yea, I went back after work last night, and pulled the rear diff out. it's dry and locked. so apparently I had a leak. Also the car is exactly 10 miles from home, and the basic AAA service only covers 5. so I'll be swapping in the new diff on the side of the road. yaaayyyy

 

I got an RS rear diff from a buddy that the LSD in that is locked up. But it's 4.111 and the R&P are fine. so I'm going to swap in a carrier that uses bolt-in stubs, and I should be set.

 

 

I'm not sure if I should try to use this LSD again though. I haven't had a chance to open it up and see what exactly failed, but I'm hoping it was the pinion bearings or something that failed, and the LSD carrier is still usable. Thoughts?

 

if not, I have the open carrier that came out of that legacy diff, so I can use that.

[Numbchux]

Well...the car is home. under it's own power.

 

 

got the old diff home yesterday, and pulled apart last night after work. the pinion is seized in the case. it won't spin, and I beat on it for awhile with my maul, and it didn't budge. I might put it on the press and see if I can't get it out....but I don't think it's coming out.

 

 

Got this other 4.111 diff from a buddy from his Girlfriend's RS. the spider gears were quite trashed, but ring and pinion in good shape. so I pulled it apart, and put a new carrier in it.

 

I opted for an open carrier, for a few reasons. 1: I would have been waiting on the LSD additive. and the case would have required grinding to get the LSD carrier in it, and the grinder was in the XT6.....10 miles away.

 

So I went this morning and bought a quart of gear oil, and a tube of loc tite. finished assembling the diff. By girlfriend and I loaded up the Kia, and drove out there. Didn't take long to get the new diff in.

 

Of course, the battery was dead. So we hooked up the jumper cables, and boy, that really put a lot of load on the kia. Oh crap.....I put them on the '6 backwards. Long story short, black fusible link and ECU fried. luckily I had spares of both....and after an extra trip home, was driving my repaired XT6 home. and it only cost me about $15 (for the gear oil and loc-tite).

[eulogious]

Congrats on making it home! It just seems like something was bound and determined to not let you get that car home! Glad it's fixed man.