How do they check a torque converter?

hotchkiss · May 6, 2013

Need some help from the mechanical folks out there. I have a tractor in which I think the torque converter is not working correctly. How do they check to see if one is working properly. This is in a 100 hp tractor.

I loose power too easily when plowing. They checked PTO on the dyno and the engine was fine, but I didn't think anything was wrong with the engine. The problem is getting the hp to the ground so to speak. When I plow I can't even get the tractor's engine temperature to raise and it is very sluggish. It gives out way too soon in my opinion. The only thing I can think of is a defective converter.

pjbci · May 6, 2013

Whats the tractor?

Danscaper · May 6, 2013

if a torque converter isn't working, the engine rpms will go up but the transmission speed will slip. Don't know of any way they test that.

RickB · May 7, 2013

Torque converters are tested via a 'stall speed test'. A published engine RPM figure at which the engine runs while trying to move the tractor in a particular gear selection with the brakes fullly locked.

hotchkiss · May 7, 2013

pjbci said:
Whats the tractor?

JD 6330

the old grind · May 7, 2013

What was that about low 'engine' temp??? A defective thermostat will cost you power & economy if your engine isn't getting up to temp, though that should have been apparent when you dyno-tested. Some tractors have a torque converter oil temp sensor, but don't know about JD or whether an engine control system compensates somehow.

Auto TCs usually have a one-way roller-sprag clutch (stator to its non-rotating shaft) that could give out and cause a loss of power transfer. (not the same as a 'lock-up' clutch, btw) A stator clutch can be bench tested if you're familiar with the inner workings of TCs but it's a big job getting a TC out of a tractor. If the JD's TC has a lock-up clutch (doubt it) it might not be getting proper actuating pressure. If the stator clutch went south you may find pieces of it in the reservoir. I'm sure this won't help much other than point out there's more than one possibility to consider.

I hate to visit a thread without learning something. My assumption is that it's 'shuttle' &/or 'reverser' models that have TCs, while plain gear & hydro drives would not. If so equipped, can we rule out the reverser just yet, or could their clutch(es) be slipping due to loss of flow or to an EP supplement (MMO etc, the bane of hydraulic clutches in general) having been added to a 'combined' fluid system.??