Farm Equipment - D21 magnetic filter

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D21 magnetic filter

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=210593
Printed Date: 01 Apr 2026 at 1:20pm
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com

Topic: D21 magnetic filter

Posted By: whatscooking
Subject: D21 magnetic filter
Date Posted: 01 Apr 2026 at 6:03am

Just got my I&T manual for a D21 and see the filter asembly inside the left frame rail is to be serviced every 200 hours. Had one shop say to get rid of it.

Replies:

Posted By: DrAllis
Date Posted: 01 Apr 2026 at 7:30am

That filter was used on D-21's s/n 1001 thru 2520. From then on, it wasn't there. The earliest One-Ninety's and XT's also used a similar filter up to s/n 14,965 and it too was discontinued. As I understand it, there were times the hydraulic pump would lose its prime after an overnight shutdown the next morning. Also, the filter hampered oil supply in cold weather. They found the elimination of this restriction seemed to improve those situations. Do as you want. But, if you chose to keep it, clean it regularly.