JD 355D loader won't move?

The guys that bought my 1987 (last year) JD 355D loader need some help. I'm pretty sure that the reverser was/is leaking into the final drive case. They kept adding oil to the reverser and the level when up in the finals. I've heard that's a common problem. I haven't talked to them in over a year because the one guy backed out of buying my garden tractor after using it for 4 months and even breaking the blade engagement cable so the blades always kept turning. Anyway I talked to him and I said I'd try and get him some info. Apparently the machine stopped moving about a year ago. The reverser used to work good. It shifts gears without grinding but won't move at all now. They were going to pull the engine to try and see what's wrong. Some help from the JD experts would be appreciated as to what to check and how to proceed to find the problem. I don't want to have to tell them it's going to cost thousands to fix or they'll blame me. It did take me a long time to finally get paid for the machine. It runs great and has almost new undercarriage. I say almost new because the bolts came out in the end of the axle on one idler and they kept running it. It wore grooves in the idler blocks. They got that kind of fixed but the axle for the idler was wrecked. I gave them the old idlers to take the best axle out of to reuse. It was a little sloppy but they are pretty cheap. The bolts came out for some reason, the first time, and they caught it right away. I told them to put lock-tite on the new bolts so they wouldn't come loose. They didn't and the bolts came out again. Don't know why they came loose? Now because they don't believe in finding out why they have to keep filling the reverser, the machine won't even move. I said I'd try to get some info for them. I completely rebuilt the finals and put new brake bands in it. I found the duo-cone seals for way cheaper than the JD price. The last time I saw the machine, I think they said it got barbed wire wrapped around the axle. They hardly ever clean the mud and manure off the track frames. This gives you an idea of their maintenance and common sense. Thanks in advance. Dave

First, you need to identify why it stopped moving. The reverser runs at 135-150 PSI - and power runs through a hydraulic clutch pack in the reverser - and the same pressure oil powers the hydraulic clutch packs in the steering clutches.
So, if oil pressure gets low in the reverser - everything slips. And, since steering clutch packs often leak, that's why reverser oil goes down, and steering-clutch oil levels go up.

Your machine does not move - and I assume you have no idea if it's the reverser slipping, steering clutches slipping, or both?

First thing to do is stick a pressure gauge in the reverser control valve and check clutch operating pressure.

It's not mine anymore. I will let them know and then come back when I learn more. I think they parked it one day and then when they went to use it, it wouldn't move, but I'm not real sure. It could have stopped when they were using it. How do you hook up the gauge? Thanks. Dave

The test ports are on the reverser control valve..There are 2 - 1/8 pipe plugs on the top surface of the control valve..The one that is drilled at an angle is the lube oil port..The one thats drilled straight down is the operating pressure port..

the old 350's were bad about stripping the coupling that connected the back of the transmission shaft to the front shaft of the rear end. The coupling striped out & stripped both ends of the splined shafts off, making it necessary for all new or used parts. You would be driving along & it just quit moving. Motor ran good, everything worked fine, it just didnt move.

That certainly is a problem - but it's caused by other factors. Once the reverser and/or trans has been removed once, it just about never gets put back in tight enough. Then, the reverser case moves against the transmission case and wears out the locating dowels. After that, the cases don't run in-line with each other - and will keep on wearing out splined shafts and couplers.

If the first thing to check when looking to buy any 350. Look closely where the rev. case bolts to the trans. case. If any signs of movement - walk away and don't look back.