How to Determine the Return Line to a Transmission on a 2007 Toyota Sienna and 2012 Chevy Traverse

Updated 08/07/2012 | Published 08/06/2012

Question:

Hi: I would like to install a transmission filter on my 2007 Toyota Sienna LE AWD and 2012 Chevy Traverse LTZ AWD. Which line from the radiator to the transmission is the return line? Is the return line the lower one coming out of the radiator?

asked by: David N

Expert Reply:

On the Toyota if it is rear wheel drive or you have the A55 or A55F transmission then the rear line is the return line. If it is a front wheel drive model (excluding the A55 or A55F) then the bottom line is the return line.

On the Chevy there are many possible options depending on which transmission you have:

TH125/125C (3T40) = Top
TH180 = Rear
TH200/200-4R = Bottom
TH325/325-4L = Top
TH350/TH350C = Top
TH400/3L80/3L80H = Top
440-T4 (4T60)/ 4T60E = Horizontal Case Fitting
700-R4 (4L60)/ 4L60E = Top
ST300 = Top
4T80E = Lower Front
TH425 = Outer, Far from Transfer case
MX17 (Sprint) = Bottom
Toy A130L (Spectrum) = Bottom
Jatco F3A (Nova 3 spd) = Bottom, Nearest Pump
Toy A130L (Nova 4 sp) = Bottom
Aluminum Powerglide = Top

Another way to determine which line leading to and from a transmission is the return line there is a simple test you can perform. Start the vehicle and place it in gear for about 10 seconds. Then put it back in park and turn off the motor. Feel both lines. One will be noticeably cooler and that will be the return line.