Manager Forum

We have this truck in again; the dealer has done axle seals, we have replaced them twice also.

Vent tube is clear, differential has been serviced, there is no sign of metal in fluid. Bearings have been inspected and axle hubs are smooth (no roughness to cut seals). Jasper tech "replace unit", no TSBs that I can find. On older units, you used to be able to put a sleeve on the hub with a new seal, nobody seems to have or know where to get them. One old timer said try new bearings, if that doesnt work, replace the rear end.
Vehicle has 67k on it and is not being overloaded.

Customer would rather not replace the whole unit due to cost. (It is a local government vehicle)

Any ideas would be helpful; it is a full floating axle in A GMC 3500 series van.

Thanks, Bob

By "Jasper tech "replace unit" " do you mean the rear end is a Jasper? Or a call to the Jasper Tech got you information telling you to replace? If it's a Jasper maybe the axle isn't the OE size at the seal surface??

It the origional axle, I just called Jasper for ideas.

national makes them. i've called jasper and gotten the part # on more than one occasion. is the truck being overloaded? is it just one side? i've seen them blow the seals because of heat.

I have had a similar issue already and went to Chicago Rawhide seals. In some applications, that is the only brand I will use.

this may sound a bit off the wall but i've had issues where the bearing race wasn't seated properly from the first replacement causing seal leakage. i have a fleet of construction vehicles with floaters in them and have had issues with seal leakage. i've found on the tube surface where the seal rides there are slight deviations in the surface causing seal failure. i wish gm used the same seal type ford does. well anyway, i've removed the race and used diff shims to move it .025. it gives the seal a new surface. another tip is to grease the seal before you install the hub.

I've seen when using bearings made in China, there can be as much as .0030 difference in the outer or inner diameter of the bearing. This allows the bearing to be slightly loose. I had one (National Brand) some years back that fell into place, no tapping, no press or whatever, it was that far off of specs. The parts store will say well it doesn't matter, but we know it does. I insist on bearings made in USA, Germany, or Japan. The specs from bearings made in these countries are usually right on the money even though they may all be the same brand.

I also had an axle tube that was bent one time that really took me for a ride until I began taking some measurements.