I have a general question that no one seems to be able to answer. I had a job interview and was doing very well until this question was asked:

How do you test a torque convertor when it is out of the vehicle, and on the bench?

Please help me out guys as soon as possible, possibly even step by step?

 

with a torque converter tester?

 

There's some way to measure the endplay of something inside the converter. I saw it done in a magazine once a while back, which is why I can't be more specific. Ede's right, there's a tool for this.

 

actually i was guessing. i looked in snap on catalog but never found anything, but like everything there has to be ways to test.

 

Someone makes one, but if I remember right the article used a homemade setup with a dial indicator. I think they were measuring the endplay on the stator assembly from the snout. This would tell you if the converter had ballooned out.

 

AFAIK there's no way to "test" one except under some reasonable simulation of actual operating conditions. The only "bench testers" I've ever seen was when my late little bro was working at TCI, and later a local trans shop; they used an engine on a stand that they would bolt them to and run them.

 

Well, for a truly dynamic test thats true. There is some test that will give you soem indication though. Obviously it isn't a thorough test, as you couldn't test the lcokup function or other parts of the converter.

 

I was talking with my grandfather who used to be a GM engineer [he is very elderly now though] and he was saying that if you can turn the torque convertor backwards then the torque convertor is no good. If you can't move it by hand then it will be good....something about a ratcheting action.

I know this is pretty rough, but it's closest thing I have to test a torque convertor by hand on the bench.

 

Well, a converter has a sprag (one way roller clutch) in it that is only supposed to allow it to turn in one direction. If the sprag is broken then it could turn the other way, so I think he's right about that. Those old guys usually know their stuff.

 

The only two things you can check on the bench with "common" tools are stator end play and if the sprag is working. You can check stator end play by bending a coat hanger 90* on the end (sticking out about a 1/4" or so), sticking it down through the hub opening and grabbing just below the inner splined area of the stator sprag with the "hooked" end of the coat hanger. Then lift up and down and try to measure the range of travel (not so easy to do). If memory serves, anything over .050" is considered excessive and usually indicates either worn thrust bearings or a balooned converter. To test the sprag, just spin the same splined area both ways (I do this with long, straight, skinny external snap ring pliers). It should be easy to turn one way, and hard the other, indicating that the sprag is good.

 

You could put it on a torque converter dyno, but I don't know if that counts as "on the bench".