Farm Equipment - D21 rear axel seal

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D21 rear axel seal

Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=211597
Printed Date: 18 Sep 2026 at 9:32am
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com

Topic: D21 rear axel seal

Posted By: whatscooking
Subject: D21 rear axel seal
Date Posted: 06 Jul 2026 at 10:39am

How does the procedure go? Does the whole axel housing come off?

Replies:

Posted By: Alvin M
Date Posted: 06 Jul 2026 at 11:41am

NO the seal is out at end of the housing four bolts must take the wheel and hub off

Posted By: whatscooking
Date Posted: 06 Jul 2026 at 11:52am

Thanks

Posted By: SteveM C/IL
Date Posted: 06 Jul 2026 at 12:24pm

While there check for axle play. I don't know how it is established but you don't want a floppy axle which could also make a seal leak.

Posted By: whatscooking
Date Posted: 06 Jul 2026 at 2:03pm

Iam trying to figure out what the previous owner was doing inside the rear end. It failed a dyno run so off comes the lift arms. Have found clutch pack problems and insufficient clearance for the PTO shaft to turn freely. There was evidence the housing was off recently. Can't believe anything the previous owner told me about the tractor.

Posted By: DrAllis
Date Posted: 06 Jul 2026 at 4:05pm

Axle end play is sometimes an issue. The inner axle bearing cup may be the wrong one if the axle is too loose. That inner bearing cup should have a square OD shoulder, not rounded, to fit up tight against a snap ring.

Posted By: DrAllis
Date Posted: 08 Jul 2026 at 10:39am

It's been brought to my attention something that I had forgotten. It's been 30 or more years ago since I had a D-21 rear end apart. I do remember having the lift arm housing/PTO removed, to remove the inner axle bolt that retained the bull gear to the axle. I also remember having the axle housing tube removed replacing axle bearings and cups. That is why I remember that inner bearing cup (70253375) needing a square shoulder on it, to fit tight against the snap ring. Anyway, there are TWO seals on each axle housing tube. The OIL seal (70238940) is close to the inside of the inner bearing and cup. The GREASE seal (70238934) is on the end of the axle tube housing in the cover that has the shims. There is a grease zerk out there on the end of the housing that requires a seal running against the axle. So, if you have oil leaking there, the inside axle seal is leaking, allowing oil to migrate down thru the housing tube to the grease seal. Thanks for reminding me, Dean. It was nice talking to you.