I have decided to do a flush of my auto trans. Which is the cooler return line?

 

Rear line on the trans is the cooler return.

 

Hi,

Not to hijack this thread too much, but how fast does the fluid come out of the return line? 1 qt. in ? seconds?

I ask this because it would be helpful not to have to add fluid continuously while draining. If I could fill it up, run the truck for 15 seconds, fill it again, and so forth, that would be great.

Thanks,

 

It comes out pretty fast. I usually start the truck, put it in neutral, climb out and watch the fluid coming out. When the flow slows down it is time to fill again. Never measured the time, just watch for fluid flow to slow.

 

I used a clear 5/8 I.D. on rear trans line and put the other end of the hose into a clear bucket that i had measured out about a gallon and marked with a paint pen. The bucket is a 3 gallon size. With pan re-installed, new filter, and 4-5 qts. of new fulid back in pan. Started up engine shifted to "N" and let it run untill it got close to the gallon mark on the bucket,then shifted to Park (fluid does not flow in park). Empted the clear bucket. Then poured 4-5 qts. back into trans and shifted back into "N" ran untill the fluid got close to the mark on the bucket. Repeted the steps above untill 16 quarts have been poured into trans. I might add that during the steps of fluid flow i shifted into all gears, just to be sure. The transmission holds 16 qts. Drove it around some then checked the fluid level.