JD 4350 / 4240S - what to look for when buying used?

I dunno, we've had 2 4240's with no real issues. The first one didn't have a cab and it was mostly used for loader work/ aka bulldozer. The one we still have has 7200 hours on it. Mostly use it for shredding.

Thanks! I just bought this tractor one hour ago, so I'll have to deal whatever comes...
I but I've checked around as good as I can, these tractors seems quite reliable.
This is built German but I think from American parts, so it should be the best from both sides of the Atlantic!