Have an 02 Sub with a 4l60e. The tranny spewed some fluid and the gearbox now shifts only on cold start to D or R, but if shifted back to P and then to a drive gear, simply revs. Feels like torque converter not locking up. I would assume it is either the TC or Trans, or both. Truck has a rebuilt 5.3 and unknown mileage on trans.

Should I do a filter change and flush and test that, or, replace TC or rebuild trans and add new TC?

Thanks, considering all options.

 

How many miles on the sub and have you ever done a trans fluid/filter change. I'll bet it's time for a new tranny, sorry

 

Welcome to the forum. Let us know how it works out for you.

 

Whatever you do, don't flush the transmission, as that will only bust loose deposits inside the transmission and torque converter that make issues even worse. On an old transmission of unknown maintenance history, draining the pan and replacing the filter is about as far as you want to take it.

While this is not a story of a GM 4L60E (2 of those are in my driveway!), I had a transmission failure on a Subaru recently, and it was the TC lockup solenoid. The car still drove in all gears, but when you got up to speed, the torque converter wouldn't lock, causing the transmission fluid to overheat, and in turn, the idiot light for transmission overheat to come on ("AT Temp") once you drove about 2 miles. I pulled the valve body, replaced the TC lockup solenoid, and all is well 3000 miles later. I was just lucky that my ODB2 reader was able to read the transmission controller codes and pinpoint the failed solenoid. The dealer wanted $5000 to fix it (replacing valve body and torque converter), no 3rd party transmission shop would touch a Subaru CVT, and I fixed it for the cost of a $50 solenoid, a cover gasket and 5 quarts of CVT fluid.