97' Differential Grind

[quick061]

I have a 97' that I had the differential drained and filled by a mechanic about 6 months ago. About 2 or 3 months ago, it developed a noise and vibration from the rear end that happens while turning at lower speeds and while your on the gas but only when the car is already hot. I checked the differential and it was actually overfilled with fluid by 3/4 of a cup or so.

A friend of mine rode in it and said it was likely the axle bearings or something. But I've been browsing this site for the last few weeks to see if other people have been having similar problems and am wondering if the mechanic just did not put in the friction modifier and that could be the cause.

Well, that's about all that I can think of. I know some of you guys really know what you're doing and was hoping to get some feedback on this. Any ideas would be greatly apprecitated.

 

[monsta]

1. Do you have a Limited Slip? As you probably already know, they need the friction modifier. If it is an Open Diff, then it doesn't need and it sounds as if your side gears are bad.

That sucks because it ain't real cheap to fix.

Are you certain he used the correct fluid?

 

[quick061]

How can you tell if its limited slip or not?

I remember when the guy did it he said that it took special synthetic fluid, plus it has the tags on the plate bolts that they would have had to have seen when they popped it off, so I'm assuming he knew the right fluid for it.

As far as the modifier goes, is it something that I can pick up at a parts store or only the dealership?

 

[monsta]

You can look at the axle code of the door jamb label.

If it is two digits (numbers) then it is an open diff.

If it a letter followed by a number then it is a Limited Slip.

Friction modifier can be purchased at NAPA. You gotta go to the more "hard-core" auto parts stores versus the "soft-core" ones like Auto Zone.

'Course it doesn't hurt getting it at the dealer. At least then you'll know it meets factory specs.