Transmission lines leaking?

anm8 · November 21, 2018

Hi everybody,

Just bought my first GMC a week ago. It is a 2016 with 55,000 miles 5.3 SLT 4x4 with Z71. I looked the car over pretty good but noticed something after we got home. Is this the common leaking crimps I have been learning about on these vehicles with transmission lines? I have to crawl under the vehicle this weekend but this was the picture I was able to get. The gunk had no smell to it at all.

And not sure if the Rancho shocks are completely shot on this Z71 package but on the highway and my first speed bump the words....Old Cadillac came to mind about how much it wallows. Thanks everybody for your time....

Edited November 21, 2018 by anm8
added a line

MaverickZ71 · November 21, 2018

Unfortunately, it is very common for transmission cooler lines and oil cooler lines to leak on GM products. I had lines replaced on my '96 Impala SS multiple times, and also on my '09 Silverado. Now my truck is leaking again; 3rd set of lines. And I don't race/heavy haul/tow with my vehicles. The dealer always use the real GM replacement parts, so apparently those parts are just no good. They last about a year before they start to 'sweat' at the crimps, and then progressively get worse until they drip. They say you can cut the crimps off with a Dremel tool and put on hose clamps and tighten the heck out of them and the leak will stop. Or have lines built for you at a shop that specializes in hydraulics.

A lot of people on this forum have replaced the factory Rancho shocks with Bilsteins.

Edited November 21, 2018 by MaverickZ71