Crawled under the car to check the oil level in the rear end. The entire bottom of the gear box is fairly moist with oil. It does not look like it is coming from around the shafts. It drips a little, but does not make a puddle. Is there a plate or case gasket that can be leaking? What should I check first?

 

Did you recently have your fluids changed? If so, it is possible they could have left the fill plug a little loose. Otherwise, you are probably looking at either a pinion seal leak, or a cover plate leak. I would clean it real good with brake clean and determine EXACTLY where the fluid is seeping from.

 

I had this happening to my '85. I thought I had leaking seals. At first I thought I had a pinion seal leak. Turned out that the oil was leaking past the splines of the pinion. When the driveshaft is disconnected there is a large nut with a washer underneath that is used to hold the input yoke to the pinion shaft. The pinion shaft and the yoke are both splined for mating, the yoke slides over the pinion shaft. What was happening was the oil was seeping from inside the differential along the splines and out from under the washer and nut. I think the factory may have used some kind of sealer to seal the splines under the nut and washer. Maybe my spline and yoke are just worn enought to allow the oil to seep out. The silicone under the washer and nut worked for my leak. I found this out when I removed the rearend and used air pressure in the vent at the top of the rearend. I could then see the oil coming out behind the washer.
Another leaking area which I believed the factory fixed on a bulletin was along the bottom of the differential between the carrier and rearend. GM drilled and tapped another bolt along the bottom edge of the rearend to prevent leaks. I don't know if yours has been modified. :steering:


[Modified by MrRenoman, 12:38 AM 7/14/2003]