I want to pull the front pump and radiator from a J model D2. It is an aftermarket pump. My question is "can I remove  them together", and do I have to remove anything from the front of the crankshaft? Should the pump splined shaft just pull out of the piece that is bolted to the crankshaft or do I have to unbolt that adapter?   Thanks,  Grant.

Should just pull off the splined driveshaft. But how big is the overall assembly? What brand pump?
If you had the CAT #41 or #44 it's best to pull the hydraulic unit first then the radiator.
The coupling on the pulley does have bolts holding a cover that encases the big splined end of the driveshaft.
Those would need removed if the radiator/pump can't slide out. Then pull everything together.

Grant: How come you don't want to remove them separate? Seems easier when done in pieces here; splined shafts generally pull straight out; seen many coupled with roller chain or Lovejoy coupling as well. Engine hoist or suitable lifting device a must here. JM

The pump does not seem to have any identification and is mounted to an adapter on the radiator. The bolt heads are such that a wrench or socket cant slip on to them. I have reached around behind and cant find nuts to loosen, but I will use a mirror and light before I work on this. The mounting holes on a J model are different than a U model and there is a cast piece that bolts to the crankcase that the pump actually bolts to. It looks almost like a skid-plate with ribs. , My other J model D2s dont have this plate.

This machine started life as a Traxcavator but I would not think that they would have used anything but a normal Cat pump on the front. Maybe the original pump died and this pump was a cheap replacement? There is a lot that I dont know. Thanks, Grant.

Engine hoist is definitely going to be used. Thanks, Grant.

Interesting. Would like to see the differences. Got some pictures? I have 8- 5UD2's but never scored any "J" model D2's.

I will again try to post photos. I am a Ludite , so there is no guaranty it will work. My 5U has the same pump mounting area as my D4s, but the Js are different.
Grant.

As soon as you said "Traxcavator" your descriptions of the radiator support/pump mounting started making sense - the radiator support on the left is the piece that Caterpillar made and is what originally came on all J series tractors. The support on the right is a part of the Traxcavator kit and was not made by Cat but was installed when the rest of the conversion was being put on. It has the extra mounting flange on the front to support a part of the mechanical drive system that powered the lift for the vertical mast. Cat never offered a factory radiator support with this provision for live power on the "J's" but I kind of wish they had. Instead, the later #41 and #44 hydraulic unit manuals just show to cut out a chunk of the stamped steel radiator shell and weld in a heavier piece for pump mounting. Also, removal of a non-Cat hydraulic pump may become more or less complicated depending on how they chose to make the drive setup - I've seen some that were very clean and well done and others that were real head scratchers lol

 

Something about my above post jogged the old memory banks, and I couldn't shake the feeling I'd seen an illustration of a similar radiator mount to the one I stated was not made by Cat in the pictures. I looked at it again and found it in the 5J parts manual, the one with the extra mounting flange is the "6B7231 bracket" as used in the 8B9544 Front Power Takeoff Group in the "Accessories" section. So Cat indeed did make that support, I just wanted to correct my mistake.

So This bracket was just a place to bolt on the outboard bearing for the belt sheave. Or future hydraulic pump. That make sense.
I like your description for the #41,#44 Toby. " Cut out a chunk of the radiator shell" LOL
I know where I can pickup a 3J with the Trackson loader. I'll have to check that out.
Maybe the gas wrench is going to help GrantJ remove the pump bolts.