All the shaft splines & couplers in the driveline (& pto line if so equipped). Also the pulleys as they have splines as well, plus the V in the pulley can wear to where belts can grip proper. Then of course check for proper hydro function. All the rest is general stuff like wear for any GT. You can slide pulleys & couplers on the shafts to check for wear once you remove the keepers, usually cotter keys.
What ever you find it can be fixed! The splined couplings and shafts are the biggies. The splined input shaft on the hydro is the hardest to fix. Tranny dipstick is under the seat, pull it. Red and rusty is ATF, Golden or bronzed is Motor oil, either is ok. The motor is an Onan so any major repairs can get expensive. No 3pth would drop the price considerably, rear PTO not so much but nice to have. The decks are OK but between the timed pullies and the blades being NLA its not a deal breaker if its busted up.
These are Beast machines, loaders and backhoes can be bought or made for them and they handle them well. The users lay outs are great. They were ment to be used.
There have been some ads that state XX55, but the pic will show a XX50. The easiest way to tell the difference is XX55 has a twin cylinders and 6 bolt rims, XX50 is single cylinder and 5 bolt rims.
I hoped to stop by on Saturday, but of course there was another interested buyer, so I decided I could go today! Notice the three point hitch? Can you say PLOW DAY? I called at 3:00 to confirm that I would be there around 5:30, she said she might be a little later than that. I pulled up in her driveway promptly at 5:30 and began to wait. I tried to call at 5:40 and again around 5:50 but the phone rang and rang with no answer. Maybe she is really good about not talking on the phone while driving. The house looked like a single story ranch style, but there were two cars in the driveway, so even though there were no lights on, I went and knocked on the door and rang the bell several times. No answer.
I really didn't want to be crawling all over the tractor when she pulled into the drive, but shortly after 6:00 I pulled out my flashlight and started looking. I'll detail that in a bit. After I'd looked it over, I got back in my truck and started studying for my exams next week. At 6:45 (just about pitch dark) I see movement in the driveway, and a teenager comes over and asks if I'm there to see his mom. Turns out they have been home all this time, they live in the basement which can't be seen from the front of the house and the phone has no service. I'll have to say I was pretty unhappy.
The tractor looked pretty good. She admitted it had been sitting out in the weather for the last "8 months", and water was sitting on the footboards and causing some rust. The rear tires were new enough that they still had the little nipples on them, so right there is at least half her asking price. But the bad just kept piling up:
Headlight wires cut off and taped up
Ignition switch doesn't work
Battery is dead
"Tractor runs" I got her to admit it had been at least 18 months since it last ran.
No belts on front PTO, loose wire hanging nearby-don't know where it was supposed to go.
PTO shaft turned, but felt a little rough, maybe bad bearings, maybe not.
Quite a bit of rust on all PTO pulleys
Half of mower deck drive shaft missing
Remaining half frozen at an angle
Ignition coil was loose in its pocket, and had a hose clamp around it.
Drive pulleys extremely rusty, possibly pitted.
Drive belts almost worn through, so loose they would lift off pulley.
Drive shaft- the adjustment plate on the engine end wobbled and felt loose. Couldn't tell why.
Driveshaft-rear yoke wobbled, I assume that is the NLA coupling but wasn't quite certain.
Hydro fan blades broken and fan loose on shaft- just one more thing.
The engine turned freely, but I never really felt any compression. Not conclusive, but not very confidence inspiring.
As might be expected, the gas tank smelled like varnish, so an entire fuel system cleaning would be in order.
I looked at that tractor and I thought hard about it. My wife told me I should buy myself something nice for Christmas, just before I saw the picture which showed me that this was a 1655. In fact, when she saw the picture she said "That's MINE!" But I walked away in the end. Wasted my time driving (4 hours total) and sitting (over an hour). After looking it over, I decided it was just too much of a project for me, I've barely had any time for working on the tractors I have, let alone using them. I'll be posting this over in the "finds" section shortly, it would be nice to see someone from here get it and put it back in working order, but I don't think I can be that person.
This tractor turned up again, at least I'm 90% sure it is the same one. Asking price went from 350 to 1450. While the seller claims it drives, I see the mower deck is still missing half the drive shaft, still appears to be frozen at the same angle, and who knows what other issues were left un-addressed. Also, I remember that odd trailer hitch as well. I have to say, part of my thinking when I declined to buy it was that there was another interested party who wanted it. I assumed they wanted it to use, not to flip.