rear end differential buzzing , grinding? ....???

Question

97 MAZDA B2300 PU TRUCK 4 CYL.
TRUCK WAS LOWERED AND DROVE GOOD FOR ABOUT 6 MONTHS.

DIFFERENTIAL SITS AT DOWNWARD ANGLE DUE TO THE LOWERING.

I HAVE 2 PROBLEMS.

ON JACKS WHEN I ACCELERATE AT AROUND 45 AND UP I HEAR A BUZZING NOISE COMING FROM THE REAR END. SOUND LIKE THE GEARS OVERWORKING????

THE OTHER IS THE DRIVER SIDE REAR DOES NOT SPIN. THE PASSENGER SIDE IS TO SPEED BUT THE DRIVER SIDE BARELY SPINS OR DOES NOT SPIN AT ALL????

Answer 1

The u-joint at the diff. may be the cause. They are designed to operate at a working angle no greater than 15 deg. If the angle is greater than 15 deg. then a constant velocity u-joint assembly needs to be fitted to the driveshaft.

To inspect the u-joint:
Drop the driveshaft & carefully remove the cups. The bearing surface should be shiny & smooth. Check in the cup to make sure all the needles aligned & no broken or missing.
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To check that the diff is operating correctly:
Suspend the rear axle on jack stands.
Place the trans in PARK - engine off – brake off, or in neutral, have someone hold the driveshaft.
Spin one wheel by hand.
The opposite wheel will spin in the opposite direction.
Another way is to have your assistant hold one wheel & spin the other, the driveshaft will turn - then switch sides.
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Answer 2

Did you lower it so much that you need to shorten your drive shaft? There is a slip joint on your shaft make sure it is not bottomed out when vehicle is on the ground with entire weight of car.

Answer 3

when you had the truck lowered, you should have had the differential changed along with the other parts that should have been adjusted or modified

Answer 4

ok the ringgear and pinion are ground up... as far as spining wheels unless u have locker or posi rear you have "open rear" its normal