Went to change both my front and rear diff fluids yesterday, rear went fine but when I opened up the drain bolt on the front no fluid came out. I filled it up and took it for a drive no problem but then this morning I see this big puddle of gear lube under my truck. Hopped underneath and pinned it to drivers side of diff, right where the CV plugs into the differential.

I can wiggle the CV shaft a little bit, does this mean the bearing is bad inside there? Or I have read about a "scored" axle, could this be my problem considering it could have been ran without fluid for quite some time? I'm sure I'll be replacing the seal, at the very least. I just hope my front end isn't cooked now! Also, does anyone know the part numbers, truck is a 1998 Blazer 4X4... Here are some crappy pics I took, first is looking in from outside, other two are underneath.

 

Does your 4wd still work and everything? If it does then I doubt you hurt anything up there. Mine is leaking from there as well but it's not as bad. I'd say more than likely it is just the seal gone bad.

Does anybody know the correct seal to buy for this and how hard it is to replace?

 

When I was working on mine this site helped. 1998 Chevrolet BLAZER TRAILBLAZER 4WD Driveline > Differential Parts like front seals

 

That's the thing, my 4 wheel drive works flawlessly, and there is no noise whatsoever. I'm debating whether to replace the seal and hope that nothing inside is damaged, or pickup a entire front differential from a local yard for 100$ and put that in.

Now that I've been thinking about it, the CV has quite a bit of play in it. So, my thought is that the CV has been wobbling and cause the seal to fail. Could this wobble be from something warped/ bent or whatever inside the differential?

Thanks for the input guys, I'm really just weighing my options here....

 

If it were me, I would go ahead and replace the needle bearing that the inner CV shaft rides on. It's added insurance as they do wear out and it's only a 10-15 dollar part from the dealer. (GM P/N 26053326 I think but double check). Make sure that the outer race on the CV shaft is not grooved or scoured, otherwise it will leak.

Also, use GM seal 12471586 to button up the job. (I never had good luck with aftermarket seals).

You will need a small 3 jaw slide hammer bearing puller to yank the old one out- I think they rent these at any local AZ (p/n 33627026). Just be sure the jaws are just tight enough to grab onto the bearing, but not enough to scour the bore. Also, note the press depth of the old bearing before pulling it out- this will tell you how far to press the new one in.

Tip- It helps to put the new bearing in a freezer for an hour or two before installation as it makes them go in easier. Pack a little wheel bearing grease in the needles and your ready for reassembly.

Cheers!
Joe

 

THANK YOU!
Would an attachment on a slide hammer work for getting it out? Also how do I get it back in there, a piece of wood and a couple "luv taps"? It sounds like it is pressed in some how?

 

im installing a front wheel drive transmission at work on a ford escape due to basically the same kinda failure. the bearing inside there failed. so the truck still moves but leaked like crazy so we sent it out to get rebuilt. usually if you think there is excess play in something like this, grab the other side and compare. if its equal movement it might be fine. if that side moves more then yeah its got problems. i know there should be a little bit of movement but without seeing it its hard to tell

 

Any slide hammer with a small bearing puller attachment should work fine (jaws pointing outward of course!). The bearing isn't pressed in very tight so it should come out with a couple of taps. This same tool can be used to remove the old seals as well.

A piece of wood can be used to press in the new bearing. Use your imagination, but I made my own tool by screwing a 2" circular piece of 3/4" plywood to the end of a broom stick (cut about a foot long). this allowed me to tap the new bearing in evenly and square to the bore (this is important!). With a few taps of the hammer, I tapped the bearing until it was the same depth as the old bearing (as noted before removing the old one). Press in the new seal till it's flush with the axle tube (a scrap piece of 2x4 works good for this) and presto! Your ready to install the axle shafts.