Changing diff oil
 

Hello
I have a 98 blazer LT 4wd and I was wondering what the best way is to change the front differential oil. I’ve read that these have drain plugs and some say they don’t. If not, then is there some place I can get a pump to suck all the old crap out? I just bought the thing and found both the input and passenger stub shaft seals are leaking. I figured old fluid may have caused this. Anyways this weekend I plan to tackle both seals and would like to put in fresh synthetic lube in the front and rear diffs. I will remove the cover on the rear to drain the oil. Any advice would be appreciated.

RE: Changing diff oil
 

Im doing the same thing for the rear, not really for maintance but I have to find out what gears are back there. Anyways, if I were you I'd use that rtv gasket maker stuff (the black one) instead of getting a new gasket for the cover, I've heard it works a lot better. Just my $.02

RE: Changing diff oil
 

You will just have to crawl under there and look.

From what I gather....most DO have drain plugs, but my 96 darn sure didnt.

I just used a little pump and got out all that I could. I am going to repeat the process here in a few months to try to get the maximum amount of good fluid in there. What came out was butt nasty.

RE: Changing diff oil
 

As far as the RTV goes... that is what I was planning to do, but I ended up giving up and buying a gasket.

The sway bar was so close to the cover.... I could not keep from smearing the RTV when I was trying to position the cover back into place. Maybe there is a trick I don't know about.

RE: Changing diff oil
 

I would rather use the gasket. I just find it easier to get in place within the confines listed above. I also find that gaskets are easier to clean up after. But then, that's for the rear diff...

On the front diff, there should be a drain plug. On some cases, this is one of the lower most bolts. If not, then you may have to use a small hand pump to suck out the old fluid. Then refill with new fluid through the fill plug.