Desoto45
New member
When I start up my 2006 GMC I noticed some transmission fluid leaking from the lines. After wiping them clean I noticed all three were leaking. I goggled this problem and it seems to be very common. I started taking the 3 lines off and noticed different fluids. The upper trans to aux cooler had trans fluid, The other side of aux cooler connection went to the upper radiator. Lower radiator line went to lower transmission connector. I did not see any internal plumbing in the radiator to keep the fluids separate. When I took the line off upper and lower radiator all my antifreeze came out. What fluids are suppose to be in these lines?