LEAKING Transmission Cooler Lines

i have a transmission cooler attached to my transmission. The lines that connect it are leaking around the crimp fittings.

I figured if i just cut the fittings off and used 3/8 fuel line, would i be ok. Im afraid that i might get some air into the lines and mess my transmission up

Don’t worry about air in the lines. I have repaired many rusted through transmission lines and never had a problem.

Air in the line will just vent out. No problem at all. “Crimp fittings” is too vague. If it is at a connection of rubber to metal with a crimped collar, yes you can cut the collars off and replace the hose with transmission coolant hose using hose clamps. Transmission coolant line is not the same as fuel line. Fuel line will deteriorate there. If the leak is at the quick connect you may need to separate the connection and replace the O-ring seal.

Do not use fuel line. Get transmission cooler line and make sure it is the right size.

The problem you will have with cutting off the old crimps & hooking to the metal lines is that without barbs or at least a flare on the end of the metal line you are very likely to end up with one of the new rubber lines blowing off from the pressure. I don’t care how tight you make the clamp. Odds are you will lose it and at the worst possible time (see below).

I recently had a similar kind of leak. I just ordered a new OEM set of lines and installed them. Transmissions are too expensive and the consequences of sudden fluid loss too dire for me to want to mess with it.

Air is not an issue.

Whatever you do, don’t repair it with any kind of rubber/neoprene/whatever-rubbery hose. The transmission fluid is very hot (north of 200-300 degrees) and the rubber hose won’t hold, and will go at the least opportune moment. I have the scars to prove it. Mine was repaired the first time with a rubber fuel line, and it blew out on an interstate just as I was in the passing lane. Luckily, I saw the huge billow of smoke coming from the back of my truck (it was spraying onto the exhaust manifold) and was able to pull over before I had lost much fluid. I lost less than 2 quarts. After the cost of a tow 200 miles from home and a temporary repair, I had it repaired the right way with metal lines and compression fittings. It was an expensive lesson!

I’ve used the rubber hose to repair a leaking steel line but you absolutely need to double clamp it. I also had a hose come off from an add on cooler that the trans shop put on that was only single clamped. All they did was cut the steel line and used a worm clamp on the hose. It never came loose again after double clamping it.