The Stovebolt Site Forums The Shop Area Driveline 41 3/4 Ton Pinion Seal and Ring and Pinion

I pulled the yoke off and pinion seal out this morning. The existing seal is a National but no number on it. I think the replacement is a SKF 15557. Can anyone confirm this?

Also I think I have a little excess backlash on the ring and pinion. Is there a reliable way to tell by how much is too much by rotating the pinion back and forth by hand? And if there is too much, can I adjust the backlash with the carrier still in the housing?

The backlash is adjusted by thousands of an inch. I wouldn't trust my hands to do the measuring of that, you'll need a dial indicator. Also, these do wear in over time and you can expect a reliable .003"-.005" over the original adjustment. If it falls into that category and doesn't make any noise, leave it alone.

I don't have my parts book on hand right now to give you the number for the pinion seal.

Jeff

If you are rotating the pinion without holding the ring firm you are most likely feeling play in the spider gears. You may feel up to a 1/4 turn play at the pinion this way.
The correct way to check back lash would be to hold the pinion from moving and set a dial indicator against the ring gear teeth.

Hy Harold41, the O.E.M. p/n for the pinion seal is 3663166 that crosses to CR/SKF 15557, or National 5704, hope that helps.

Thanks,
The yoke o.d. and old seal o.d mike the same as listed for the 15557 but the old seal width mikes @ 0.590. SKF lists the width as 0.313, probably won't matter since I'll need a speedi-Sleeve anyway.

Dave, You're right on the spider gears. I pulled the rear cover off and if I hold the ring gear there is hardly any perceptible play in the pinion. Even without holding the ring gear there is not as much play as I thought. The pinion moves less than the amount of one spline before you see movement in the wheel. So I'll probably install the seal and refill with fresh lube.