xandarin

Hey, I just bought a 1996 4Runner Limited 4x4 and when I accelerate, something in my rear end screams and whines very loudly. I was thinking I just needed to grease my differential? Any ideas?

khaug

Sorry to rain on your parade, but if your rear diff howls under acceleration it usually indicates failure of the carrier bearing or some other part in the differential, allowing the ring and pinion mesh to have gone bad. I'd get it to a competent mechanic soonest, as very little of this will permanently damage the ring and pinion set, requiring its replacement as well as repair of whatever caused the problem.

The differential runs in a bath of gear lube, not "grease". To check the level, remove the upper plug and stick your finger in the hole. The gear lube should be just below the level of the fill hole. If it's low, suspect that a rear axle seal has failed, allowing the lube to leak out into your rear brake drums. This is a common failure in 3rd gen 4Runners, and requires repairing the failed seals, replacing the rear brake shoes and repairing whatever damage the lack of lube has caused in the differential. There is no way you can "grease" the differential.

For your sake I hope my guesswork is off the mark, as this can run into big bucks. Good luckl.

MTL_4runner

At the very least drain and refil the diff to see iif you can eek a few more weeks out of it. I agree though that it is not a good sign when you hear that. Try to pinpoint if the noise is from a rear axla bearing or actually from the diff. You should also lube all the zerk fittings on the driveshafts.

northfacer581

yea you better watch out. i had the same problem, and it was my carrier and ring bearings...if i would have driven about 2 more weeks, my rear end would have been done. you need to get this fixed asap, and drive as little as possible.

Godzilla

I just had this noise and it was a shot rear u-joint..so try lubing your drive shaft like mentioned above