Way back in July '00 there was a short post on this.
CPFF stated he couldn't find a seal at his local Cummins place. But, he did find a seal at an industrial bearing supply place.
He didn't list a part#, but said the seal was metric sized, with these dimensions:
28mm i. d. , 38mm o. d. , 7mm wide (or wider).
He said there was also a metric sized O-ring required.
I tried to attach a scanned portion of the posting. I wasn't able to reduce the file size enough so it would fit here. If anybody would like a scanned copy of the entire post, send me your e-mail address.
It was originally posted by Rodney on 07-02-00 as "Seal" in the Products Accessories forum.