Magnet on diff cover?

Datdude541 · Jul 29, 2024

Hey guys and girls.... so the other day I was driving along, just shifting out of second to come to the stop sign for a righthand turn and BANG... my rear tires locked up at about 15 mph. I mean I thought the darn driveshaft was gonna come through the floor. Scared me more than anything. Car stalled out. Fired it back up and drove it quarter mile home. The next day doing about 25 30 it did it again. Scared me again cause this is a very violent BANG. This time though I was in 2nd gear accelerating. I started checking the axles first, then pulled the rear diff cover and I can see a ton of little metal ground up chunks. I'm wondering if there was possibly a magnet on the inside of the diff cover that no longer held its charge or whatever, slept and fell into the path of the rearend gears and that's what all these chunks are because there is no missing teeth on the gears or anything.

Miltoid · Jul 29, 2024

That doesn't sound good. Is there play at the yoke or the ring gear? it could be bearings.

Datdude541 · Jul 29, 2024

Miltoid said:
That doesn't sound good. Is there play at the yoke or the ring gear? it could be bearings.

Now I have an awful rumble somewhere in the clutch and my car makes a terrible squeel from time to time. Ya definitely gonna need bearings. I'm wondering if it could have bent my driveshaft as there is a bind at u joints. All my driveshaft bolts were loose. Grrrrr. Brand new clutch too

b1pig · Jul 29, 2024

If this was an auto transmission, I'd readily point to the rear diff as the failure point. However... having a manual...

Have you drained your transmission and inspected the oil for metal?
If "somehow" your manual transmission engages two gears at the same time, the transmission output will lock. That will lock the rear wheels, obviously and more violently than locking brakes up as the shock travels up the driveline. Is it possible that this could have caused the bolts to be loose on your driveshaft? I could entertain that idea, but I'd have no proof of it.

Metal in the gear oil of an axle consisting of a little "glitter" I would say is normal and sometimes limited very thin slivers stuck to the magnet. "Chunks" I would not consider normal. I think the weakest things in a rear diff are the c-clip style axles and spider gears. If you pulled the cover and there is nothing obvious in that rear diff, it's time to very closely scrutinize your transmission.

I have experienced a locked up manual where two gears selected at the same time. That very thing you describe happened. This was on an old GMC truck with a side-loaded manual. After market shifter had been installed and an improperly installed bolt on one arm caught the other shift arm and shifted the transmission into two gears at one time.

Good luck, sir.

95opal · Jul 29, 2024

Datdude541 said:
Hey guys and girls.... so the other day I was driving along, just shifting out of second to come to the stop sign for a righthand turn and BANG... my rear tires locked up at about 15 mph. I mean I thought the darn driveshaft was gonna come through the floor. Scared me more than anything. Car stalled out. Fired it back up and drove it quarter mile home. The next day doing about 25 30 it did it again. Scared me again cause this is a very violent BANG. This time though I was in 2nd gear accelerating. I started checking the axles first, then pulled the rear diff cover and I can see a ton of little metal ground up chunks. I'm wondering if there was possibly a magnet on the inside of the diff cover that no longer held its charge or whatever, slept and fell into the path of the rearend gears and that's what all these chunks are because there is no missing teeth on the gears or anything.

Time to pull the rear apart.

Miltoid · Jul 30, 2024

95opal said:
Time to pull the rear apart.

Don't just tare into it without knowing for sure it's the problem. If you turn the differential by hand can you hear noises or feel roughness? I doubt if a bad differential could damage the drive shaft or trans.