A4LD Trans cooler lines. Supply/return?

[Hank]

I have not done any imperical testing yet but does anyone know which of the cooler lines off the trans is supply (pressure) and which is return?

I am adding an in-line filter and temp gauge before the first cooler that has a check valve so proper plumbing is required.

Thanks
hg

 

[914x4sport]

This is merely an assumption, but if it has never been tampered with I would say the top line. this would allow the coolant to flow downwards with the flow of gravity through your cooler. Much like condensor lines for an air conditioner. Just my opinion though.

 

[Brian1]

Oh man I remember on the CCR2000 run we had this same problem out in the middle of nowhere at about 10,000+ feet of which line is which. I think we found the answer in the Haynes manual. If I had it I would look real quick but I am not close to it now. Maybe some one can look and tell you.

 

[Hank]

Thanks guys, I checked my manual and it did not go into detail on the lines. I'll play it safe and shove the rubber hoses (off of the lines before go into anything.) into some bottles and crank it over for a second. Logic would dictate that supply is the line that goes straight from the trans to the cooler in the radiator.

Will post back if I get to it this weekend.

hg

 

[Scott B.]

Hank,

I just looked under my truck (same thing we did at CCR2000!) - under the radiator, the driver's side cooler line is the supply/pressure/hot line. I would assume your '91 is the same.

 

[wabbit]

Yup, the driver's side one is pressure...

I'm hoping my tranny rebuild and addition of a pusher fan before the cooler plate will eliminate the recurrence of "tranny meltdown".
At CCR2000, it was determined that the driver's side line was the pumper. At that time it was pumping more of a ground metal paste than than anything that looked like tranny fluid.