So I seriously need to flush my transmission for as cheaply as possible and I am unable to do so directly from the transmission outflow port

My great idea is to remove the return line from the radiator (95 jimmy Slt) no aftermarket cooler. "is this wise"

I figure it would flush both the transmission and the cooler. I would just set the return line inside a slightly bigger hose that drains into a 5 gallon bucket. start the engine and drain off a quart at a time before shutting it off then adding a quart of fresh fluid to the transmission. repeating the process with every quart drained until the fluid hitting the bucket looks newish.

From my understanding of the 4l60e transmission it cycles the fluid even when not in gear so I wouldn't even have to play with the shifter and cycle through gears after each quart is drained/added.

I would really like some input from the community before I attempt this to make sure I don't screw anything up.

 

That would work but a little messy. I did mine yesterday with a pump from the local Tractor supply. LiquiVac Oil Change System, Large Engine/Project Model - For Life Out Here
I sucked out 4 quarts then added four. Drove it a while and did it again. Looks clean. I used the same pump on the rear differential, break master cylinder and power steering pump. Quick, easy, clean and cheap enough.

 

Depending on the age and history of trans fluid changes you could do more harm than good. High mileage and no changes I wouldnt bother. This sounds strange but its truth. ( one time I didnt listen to others) there is basically crud holding the clutch plates from slipping. New fluid has a detergent that will clean this crud off and could possibly cause slipping. how do I know, I did it. A few hundred miles later I lost the 3-4 clutch pack resulting in a rebuild. If the fluid looks clean, you may be ok. If it looks dark and smells burnt, dont do it

 

Trans has less than 50 thousand miles on it, Got water in it and I am just trying to postpone the inevitable though I've been told that since it hasnt been driven enough for the water to boil/foam that i've got a 50/50 chance of it being perfectly fine. Also been told that given the year it's more resistant to such things than the earlier models as the paper around the clutches in earlier models was replaced with Kevlar in the 4x4 models.

 

I'd drop the pan. Seems to me the water would settle in the lowest point.

 

Did the flush, drove it a few miles and everything seems to be in working order.

considering the rig was flooded up to the top of the drivers seat in standing water for 3+ hours/ hydrolocked / water in the transmission. would seem the only permanent damage is a burnt out srs/derm and seatbelt sensor