Rear Axle

I have an 87 K5 Blazer and when I drive about 30 miles or more I feel what seems to be a grinding noise in the rear. I notice it more when I turn at low speeds, turn from a stop and turning in reverse. Sometimes it feels like some slipping also. I have removed the dif cover and from what I can see it looks good. There is no metal shavings in the oil and the teeth look good.

Can anyone give me some advice on what the problem might be?

Do you have a limited slip differential?

Have you checked the pinion bearing?

Have you checked the u-joint at the differential?

Have you checked your wheel bearings?

It is a limited slip.

All the U-joints seem to be good. They don't have any play. I will have to look at the bearings, I haven't checked them yet.

I read last night that there is a different gear oil for limited slip and posi-traction differentials. I just bought the blazer a few months ago so I don't know what the previous owner put in it. Could that cause the problem?

Check the rear dif and see if it has oil in it and if so, does it have the right grade?

Normally if the rear gear oil is not right the posi will click and grab when turning a corner. I'd suggest an oil change in the rear end first off. Some posi units use an additive with the lube. Have to find the spec for your type of posi. There is the positraction and the limited slip, not always the same.