Transmission Cooler Lines Leaking

     Most threaded transmission cooler fittings have a O-ring down inside of them. This o-ring is either left out, lost or damaged causing the cooler line to leak even though it's tight. We see so many of these lines leaking from people that are working on the transmission themselves all because they are un-aware this little hidden o-ring! The picture below is from a Chrysler transmission in a late model Dodge pickup truck with a seal pick pointing out where the o-ring  is supposed to be. Use of the o-ring gives a sealing surface for the flared steel line & helps prevent the flaired line from cracking due to vibration & movement. ***Remember, Do not Tighten the rear cooler fitting that goes into the transmission case too much! Be Gentle or You will break the case, it's easy to do, so be careful when replacing the fittings in the transmission case. Most Ford & GM transmission's also have a o-ring hidden inside of the fitting to prevent leaks.

Cooler fitting o-ring

Below is a zoomed in photo of the location where the o-ring is supposed to be.

closeup of cooler line fitting

Hope this Helps prevent some of those annoying little spots from showing up on the floor!


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