trans cooling lines

[Dvldog8793]

Howdy
On the 1986 k5 blazer radiator, what transmission(turbo 400) line is input?
Transmission lines are on the driverside.
I always thought the top was input, bottom out?
I am adding a trans cooler.
Thanks!

[Robyn]

Trace the lines back to the tranny

On the 350/400/700 the top fitting (at the tranny) is the return line.

Normally the fluid feeds from the tranny to the top fitting on the radiator then returns from the bottom one.

Be sure to get your air to oil cooler in the line that's returning to the tranny to give the best added cooling.

If you have any doubt of flow direction, unhook the lines at the radiator, slip some fuel hose over them and stuff the ends in can, have a helper fire the rig for a second.

***** Safety*****
Place tranny in N for best oil flow and set park brake/block wheels before starting engine

You will quickly know which line delivers the oil.

Good luck

Missy