Komatsu D21A-6 right side track jammed

I recently purchased the machine back in March from an old man that really seemed to take care of his equipment. It was kept in a barn when not in use and he had the service manuals. Claimed to be the original owner. The hour meter reads 939, the paint and seat are original, and he had the steering clutches and brake bands replaced a year prior.

Well I got it to my property and was able to run it for a couple days and it was awesome, ran like a top. I backed it up inside my shop and left home for about a month and a half. Did not leave it with the brakes on and left it in neutral.

Came back to it and well when put in forward or reverse only the left track spins now. The machine tries to spin the right track, but can’t for some reason. The engine bogs trying to spin the track and ever so slightly inches in either direction on that side. When right lever is pulled the machine doesn’t bog down so clutch seems operational. I tried revving the rpms and switching quickly between forward and reverse to break it free, that didn’t work of course. I’ve checked the linkages/fluid and all seems well there according to the manual. Scouring through the manual and going off intuition, I can think of a couple problems; The brake band is engaged for whatever reason; The final drive some how seized up; Or maybe a bolt or something is hung up in the tracks. It’s weird as everything was functional before that short storage period. Any help or pointers would be appreciated.

My D21a did the same, first pull your drain plug, mine being stored mostly under cover the housing had around a gallon of water come out, I pulled my steering clutch cover and the brake linkage was all froze up. It was keeping pressure on brake band .loosened up assembly with ant-sieze and this fixed my problem

Hour meter must have been turned off or replaced . 900 hours is very little time on a dozer . Unless the machine has been drowned maybe , it still should be in a very good condition .

You would think , mine has 4200 hrs and doing both steering clutches, right side done, ( it was locked up), everything sealed up and both sides had water in them, looking at drilling the drain plugs, 1/8" putting in cotter key to keep a open drain