02 envoy Transmission

02 envoy 4.2 6l slt has a leak in the transmission line on the passenger side of engine. The line leaking is the lower line. I can't find the part number for replacement nor have I found whether I have to replace both lines as a single unit. I believe it's the inlet outlet lines from under the radiator to the transmission. Questions are, how much of the line needs replacing, the leak is at the lowest point on the line beside the transmission, does anyone know the part number or numbers required to fix, are there any special tools to get repair done and does anyone know where I can find the transmission cooling schematics for my vehicle?


Well-Known Member
I have repaired my transmission lines by putting in copper line pieces with compression fittings. As long as you have good transmission line for compression fittings to bite on, and space to get a cutter on, this is one option. What held me off the other way was buying the lines, and having to deal with getting the line fittings off of the transmission which can be tricky to get to. Also you can get pdf service manuals here on the site.


Well-Known Member
I just recently purchased my trans cooler lines for my 2002 from the dealer. There are 4 sections... joined just under where the washer fluid reservoir is located.

Where is yours leaking from? The rear lines going into the trans are a slight PITA. If you have the leak in the front then that will be easier but the junction can be stubborn.

Don't lose the small wire clips.

The new lines for the front come with the wire retainers installed in the junction. You will need to keep your old ones at the trans and the cooler....I would suggest picking up a few extra.

The passenger side line from the cooler to the junction is GM part# 15817500


Drivers side line from cooler to junction is GM 15817514


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