97 jimmy,how do i fix overheating tranny

[aeroc]

My transmission was blowing fluid out the vent tube. Someone told me I sould flush the transmission by unhooking the lines from the radiator and filling a clean bucket with new fluid and running the truck until clean fluid came out. When I tried to do this, one of the lines pumps out fliud well but the other is not sucking up any fluid. I'm lost and don't now how to fix it. I've already had to do a bunch of work to the engine and was excited to drive it again, but know I can't till I figure this out. Can anyone help?

[horse482]

Have you pulled the tranny pan and checked the filter? If all is well there then you may have the pump out in the trans. If you are blowing atf from the vent then you have a plug or it is not pumping the fluid to cool it.

[jdmccright]

You don't state if your Jimmy has 4wd, but if so, there is a transfer case vacuum switch that connects to three vacuum tubes. If this switch goes bad as it did for me, tranny fluid can be sucked up into the vacuum lines and out the vent tube as you describe, resulting in an inexplicable loss of tranny fluid and potential overheating.

The switch is cheap and so are the vac tubes, but replacing the vac lines will take a few hours of effort. I also had tranny fluid get into the front diff diaphragm (under the battery), which was a bear to clean out, plus the vacuum bulb mounted to the hood on the driver's side. I ended up drilling a small hole into the bulb to let the fluid drain out, solvent clean, then cover the hole with good high temp aluminum tape. Hope this helps!

[danorsemen]

Too weird...just signed up today to ask about this exact same thing...