Oliver 1850

I know that this is a farm tractor and I don't have ser. Number. But here the question. Both rear tires are locked so won't steal easily. It does not have a diff lock. I'm going to disassemble it and see what going on. Just curious if any advice on this was available.

I would guess a broken tooth is jammed in the spider gears.

when you say both back tires are locked, do you mean it won't move? did it do it while moving? if it has sat for a long time and is seized up, i would first pull the covers off the brakes. they are on the bull pinions and are easily accessible. the discs could be stuck to the actuating assembly and the cover or the backside of the inner disc. there are 2 discs per side. if there was a tooth jammed in the spider gears it would be like a locked differential but it would still move forward and back.

It drives just doesn't turn like the diff. Is locked. Heading out to work on it now.

ah, i see. when i read the part about 'won't steal easily' i took that to mean it was seized up. well, the spider gears are hard to get to. you can pull the long shaft that drives the pto( unbolt square cover, remove snap ring and pull out the round plug if it has one) then pull the long shaft. it goes all the way up to the engine flywheel. it can be pulled using a piece of all-thread rod. drain the diff/trans oil. then remove the whole rear pto housing as a unit. then you will see the bull gears. the diff crown gear will be visible and then you may be able to see what the problem is, but it is more complicated to actually remove the crown gear/spider gear assembly. if you tear into it farther, i would recommend an I&T shop manual for that series tractor. they are quite cheap. it should be available from an online supplier etc.

I got it apart it had broken spider gears. It all so had a broken pinion gear. Any good salvage yards .around for this tractors.

Farmland Tractor in Tangent, Oregon is a wrecking yard for Farm equipment. They tend to be a bit proud of their stuff, but a good chance they may have what you need.

If 1855 parts will work, here is one parting out.
https://www.worthingtonagparts.com/oliver-1855-salvage

We found a back half cheaper then the parts. Got it together today. Thanks for the help.

Does anyone know what kind of oil is recommended for the rearend / transmission? And what kind is recommended for the hydraulics?Thanks.

Look at the transmission dipstick. It should be stamped with the info.
If it is a diesel, Mobil Delvac 15W-40 or the equivalent.