Cooler return line fitting on my 2004

[GerGa]

Hi guys, I went to change the leaking return line fitting on my transmission on my 2004 buick lesabre and the new fitting was completely different. I bought the dorman version of what is supposed to be 04+ models with 9/16-18 thread. The threads sorta looked a bit bigger than the old one and wouldn't thread on.
Heres a pic

Also none of the rockauto suggested fittings are long like the one in my tranny. Any ideas? Thanks

[96 SSEi]

hi, I would first try some loc-tight on the original fitting and see if it stops the leak-- worked on my 93 cutlass

[nos4blood70]

Try a fitting for a 2003. When I replaced mine, they were the correct short size.

[Roadrunner]

One of the fittings at trans has a ball check in it and other doesn't.
I think Dorman only sells the one without.
Delco part number I used was 24213958 for the one with check ball.
Dorman # for other was 800-605 (which is different from what you are showing).

[GerGa]

Been a while but as original poster thought I'd check back in to share what I did.

It turns out the threads on my transmission for the return line are 1/4-18 and I bought a 3/8-18 fitting. I chose the 3/8-18 because my car is a 2004, because 2004 and up used 3/8-18, but really they were using 1/4-18 on the return line into January 2004; so my car must have been built in early January 2004.

So I replaced the o-ring on my original fitting with the one on the new fitting I bought to stop the leak.