What is this leak? It's on the inside of the passenger CV. Lip seal? Does not seem to be coming from the CV boot.

 

looks like a leak in the transaxle seal. doesnt look to bad though

 

How do you fix it? Do you have to take the whole half axle off or can you loosen a few things up on the wheel side and pound it to the outside?

 

Right front outer axle shaft seal. Half shaft must be removed to replace the seal. Don't let the front differential run low on fluid. At this point, parts are under $20, if the differential runs dry, it will be well into the hundreds.

 

Thanks - this is a winter only vehicle for us, so I might just periodically check and fill the front differential until summer. Cold weather and using the 4x4 often probably doesn't help matters.

 

80W90 gear lube, no additives, keep it full. Two plugs on the passenger side of the differential. Remove the upper plug and fill it til it dribbles out and makes a mess.

 

Thanks for the input on this. The saga continues. I finally got some time to do this today, first day here in North Dakota that I had a spare hour and it wasn't too cold to even think about it.

I crawled underneath a few weeks ago, and noticed that the plug was rounded! A surprise gift from my mechanic, I'm sure! So, I order the plug, or what I thought would be a suitable replacement plug (part #15588374) and wait for it to arrive in the mail. It finally comes, and I get to work on removing the stuck plug, starting with sockets of different types, then pipe wrenches, then chisel and hammer, then heat, and finally, I just weld a nut on there. My first welding job was crap since the area is kind of tight in there for a stick welder. Finally, the second try gets a solid weld. I remove the plug, and what do you know? I ordered the wrong plug! I got the wrong part #. The one I took out was a lot bigger. On the bright side, I still had plenty of gear oil in there, and I just topped it off and put my welded plug back on there.

So, what is the right part # for the fill plug on the front differential on a 99 Blazer 4x4? The one I ordered is on the left side in the pictures (part #15588374) and the actual plug (with a 3/4" thread bur welded on the head). The one on the left (the wrong part that I ordered) is a metric 12 x 1.5 thread pitch plug, and as you can see, the actual plug is much larger than that. So, my mission now is to track down the actual plug part # so I can order the right one this time, although I suppose there's nothing wrong with the one I have now that I can take it off.

 

As long as your weld holds, you should be fine. Might not be a bad idea to replace the plastic gasket though. Most auto parts stores should have it, maybe even the plug!