What signs begin to come up when when a torque converter is beginning to go? My machine will spin the tracks just fine, but seems slow when pushing a load. Transmission pressure guage reads I think over 400 psi.

Do converters go all at once or just get weaker and weaker. Also, what goes out? A hydraulic pump? I'm new to this so bare with me please. Is a torq converter similar to a hydraulic coupling to the transmission like on a car or truck?

Thanks for the help.

It would seem to me that the first sign is heat; if it heats up fast and is slow to cool down there is a problem. It is very similar to a torque in an auto just larger components. It would be prudent to check before total failure as this will be expensive. Most manufacturers have a stall test to determine convertor strength. Oil flow is important. Check filters.

Usually the first signs of a torque convertor problem is overheating. This is due to excessive oil in the convertor and slippage. The first thing to do is a stall test. If the stall test RPM is above spec then you can expect to find worn bearings in it. As the bearings wear the rotating parts in the convertor make contact and the clearances increase which in turn cause problems. Next thing to do is to cut open the filter and look for signs of metal in it. Another thing to do is to pull the drain plug on the convertor and catch the oil that comes out. If you get a excessive amount this is another indication of excessive wear in the convertor or the scavange pump could be your problem. You don't mention what machine you are having your concerns about but you do say that you have 400 psi trans pressure. If it is a Cat this is much higher than what their specs are.

The early bigger Cats like the 15A D8 & the D9 19A with a dry master clutch in them used fuel oil in the torque & not motor oil like all the later ones do.

I've got a 1982 Fiat Allis 11b with a 2 speed power shift. It pushes fine, but seems a bit slow. It will spin the tracks, but doesn't seem to load the engine much. It will not bog down. It also will not spin the tracks in high, but I assumed it was not designed to. It slows down considerably in low before it begins to spin. I don't use it much and it may be fine for a long time or may not be an issue at all. I wanted to know what to look for and if I needed to check anything to make sure I didn't make a problem worse.