Im checking to make sure my pump in trans is working..I pulled the top trans cooler line off top of radiator and put it bucket,nothing pumped out but it did out of the radiator oil for cooler..Does this mean its pumping or is return backing up

 

If you trace the line back the bottom line from the transmission is going to the cooler. As long as you had pressure coming out of the top then you pump is working.

 

if it was running and the fluid spraying out agreed the pump is working .

 

ls1 tech is the best!!!!