Old d4 2t wont move when warm

There should be an inspection cover where you would reach in from the top to adjust the clutch. Unbolt it to look down in the clutch housing to see if there is oil/water in the bellhousing. If there is, then crawl underneath to find the drain plug on the bottom of the bell housing. Remove it after you do a Search here to get the correct size bolt/nut combination to make a big Allen Wrench. Drain the fluids out, then put the plug back in, pour about a gallon of Kerosene/Diesel in there with it running to wash the oil/crud out. After about 5minutes of the clutch throwing the wash around, immediately crawl underneath to drain it again. Let the engine run for a bit to throw any excess out of the clutch mechanism. Drip Drain overnight, then replace plug. Actually if you are not driving it through water, you can drill a 1/4" hole in the plug and put a 1/8" cotter pin it so it will drain all the time. The cotter pin will rattle around keeping the hole from plugging! Adjust the clutch for proper engagement after searching here for the proper way to do that. You should be good to go!
Disclaimer
This was taken from memory without consulting the proper manuals but I am pretty sure you will find a drain plug underneath the bellhousing.

Hi Oldbluecat. Thanks for becoming a member of ACMOC and helping support our hobby. If you fill out your profile with where you live so it shows up in the right hand corner of your posts, there is a good chance that there will be other members in your area that could take a look and potientually give you some good advice also.

We all like pictures also.

Thanks for the responses i'm sure i will use this forum a lot more in the future getting this dozer back in to shape.

Druinjin- you're right there is a "plug" in the bottom of the bell housing as well as a inspection cover on the lower right hand side, if you're sitting in the seat, should be just below track height.

another thought is, how often and how much does the big oiler cup, which if memory serves is between the gear selector and firewall, get filled? and should the plug in the bottom of the bellhousing be removed every now and then to allow any excess oil to drain? my thought is if there's a pool of oil laying in the bottom of the thing, even a small one, while sitting most of the friction material will be dry, however once spinning/running the oil will get flung around therefore coating and soaking into the frictions causing them to slip.

There should be an inspection cover where you would reach in from the top to adjust the clutch. Unbolt it to look down in the clutch housing to see if there is oil/water in the bellhousing. If there is, then crawl underneath to find the drain plug on the bottom of the bell housing. Remove it after you do a Search here to get the correct size bolt/nut combination to make a big Allen Wrench. Drain the fluids out, then put the plug back in, pour about a gallon of Kerosene/Diesel in there with it running to wash the oil/crud out. After about 5minutes of the clutch throwing the wash around, immediately crawl underneath to drain it again. Let the engine run for a bit to throw any excess out of the clutch mechanism. Drip Drain overnight, then replace plug. Actually if you are not driving it through water, you can drill a 1/4" hole in the plug and put a 1/8" cotter pin it so it will drain all the time. The cotter pin will rattle around keeping the hole from plugging! Adjust the clutch for proper engagement after searching here for the proper way to do that. You should be good to go!
Disclaimer
This was taken from memory without consulting the proper manuals but I am pretty sure you will find a drain plug underneath the bellhousing.