How to Tell When a Torq Converter is going

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.