A D4 with a serial number in the 7U28299 to 7U43645, mine is missing the serial number gone from under the winch and left rear of the engine block. From my parts book this is the closest I can tell. I am looking at a 7U6789 as a possible parts rig the roller frames have only 4 rollers as opposed to 5 like mine. My question is the tranny case and steering clutch housing is it the same on both machines It sure lookes the same. I assume the clutch and finals are the same. Undercarriage looks good on the 6789 was thinking of moving my motor and tanny guts over to this machine and be moving. Any reply is greatly appreciated. Thanks.

If you look on the case in the rear where the plate was riveted on in between the rivets (holes) the S.N. is stamped in the casting so you may have to sand it off a little to clear the rust or paint to see it as I never saw a tractor that wasn,t stamped there in the casting (housing).Most the parts between the two are pretty much the same but there could be a few parts that are different but you,d need parts books to check everything.Earlier D4s had a dry clutch and later ones had an oil clutch but I don,t have any parts books to check what serial numbers had the changes.

As the D4U series progressed they kept updating 'em. Updates might include improved parts, difference in temper of certain parts, improvements in the engine, relocation of the fuel pressure gauge, different electric starters on the pony etc. The list is endless. Basically, parts are interchangeable throughout the D4U series (and quite a few parts in the J series as well), other than some parts within the wide/narrow finals. One major improvement (I think) is the introduction of the two piece transmission cover around S/N 16998. .earlier tractors had a one piece lid. Some parts are also different between the ones built as loaders vs blade/ag Cats.

The oil clutch I believe was an option on later units but I can't find a breakdown of when it was introduced.