I did a fluid flush this weekend for the first time. Trying to do a complete job instead of just changing the pan, since the torque converter doesn't have a plug. I followed the instructions I found on truckblog, however, fluid was coming out of the return line from the rear of the tranny as well as the line from the cooler. I disconnected it at the factory ext filter input from the cooler. I had a hose on both lines running into separate buckets to monitor fluid coming out. I was under the impression, and according to the instructions, fluid would be pumped out FROM the cooler to the rear of the tranny. The bucket for the rear hose was just for any residual fluid coming out. I lost as much fluid from the rear line as the cooler line. The fluid from the rear line was cleaner, redder. Consequently, I ran out of fluid. I could not see the bucket holding the fluid from the rear line and didn't realize it was filling up too. So this flush is going to use about 30 qts instead of 20, I'm guessing since I need to go buy more. The dipstick isn't reading anything at this point.

My question is, why was I getting fluid out of the rear of the tranny (return line) too? Shouldn't it have only come pumping out of the cooler?

 

There is a thermostat in the TorqShift. When the trans is colder than about 170°F the fluid flow is different. There is an internal circuit feeding lube to the rear of the trans when it's colder than the thermostat temperature. That's why fluid was coming out of the rear. It shouldn't do that if you warm the trans above 170°F before starting. Warm the new fluid going in, too, so it doesn't shut the thermostat while you are working.

 

Thanks for the info. I had it warmed up before starting, but it cooled down as I was working on it too quickly and I didn't think it was all that big a deal anyway since I was changing all the fluid.

Thanks again. I may indeed try it again next time. Wasn't so sure at first.