Looking at used Case & JD dozers

I've tested and looked at several already, from a 1966 350 on up. I have determined that I need to stay away from the dry clutches. Ran a 450B Case yesterday and nearly ran it through the guys hanger cause the brakes were dead. Looked at a JD 450C that had problems with the winch brake not releasing and the alternator doesn't work. Otherwise was a good solid machine with 1900 hours on it. He was asking 18k.This weekend I will look at a 450C that has a broken track adjuster. Going later today to look at a 91 Case 550 long track with about 3400 hours on it. Looks pretty clean. Same guy has a 450 (1978) with new under carriage. He's asking 21k for the 550 and 16k for the 450.

Get me 'knowed up' fellows. Tell me what I should be looking out for, and what I should avoid. I know about the tranny cases breaking on the early 450s.

Ran the 550 long track today. Machine is really clean. Under carriage looks new. Still have the JD 450C to look at over the weekend, and now have 2 more 550 Case dozers to look at. 1 in Anchorage, a 96, and a 91 in Palmer. Both around 3000 hours and good under carriages according to the sellers. I'm thinking I'll be able to tell you which one I bought next week. It would be a no brainer if any of them were equipped with the Forestry package. All 3 550's have sweeps which is good since I will be in the trees with it.