I was driving in the snow last sunday,in 4wdand smelled gear oil. then I parked my blazer and in the morning there was quite a bit of gear oil in the driveway. I haven't been able to crawl all the way under and look really well, but it appears to me that the oil is leaking where the axle comes out of the differential on the driver's side, or somewhere in that vicinity. I am not hearing any noises like bad bearings or anything, hopefully I just blew a seal.

It is a 98 blazer 4 door. Is this a common thing? what should i look for? if I have to replace the seal, how big a job is it? will I need special tools. I

 

Definitely not normal. The first thing I would check would be the vent tube. The end of it is strapped onto the driver side of the fan shroud. The other end is connected to the front diff. I would disconnect it from the front diff and then try to blow air through it. A plugged vent can cause leaks at the lip seals by not allowing for expansion of the oil and air in the diff as it heats up. If you can get some air to flow, then the vent is not the problem and it is quite possible that the lip seal on the driver side has failed.

To replace the lip seal, you must remove the CV axle, remove the seal, and press in the new seal. The CV axle is going to be the most time consuming part of the replacement. You have to remove the axle nut, disconnect the lower ball joint from the steering upright, press the CV shaft out of the hub/bearing assembly and then remove it from the differential.

 

ok, when you say "press out the cv joint" this sounds to me it is going to take more than a hammer right? I have done rear axle seals before, so I know I can handle the lip seal, but I am guessing that I do not have the technology at home to get the cv shaft out of the steering knuckle, or to seperate the ball joint for that matter. any idea what I should expect to pay a mechanic to do this job? I haven't checked the vent yet, I am hoping this is the problem, because it didn't ever leak before, and it would have gotten good and hot driving around, we got about a foot of snow on sunday. thanks.