Two years ago I installed a B&M transmission cooler. I have been fighting leaks at the connections from day one. Not much of an issue during the summer but always during the winter. I would tighten the clamps and a few weeks later a very small leak would start again. Today I decided to disconnect it and put things back the way they were prior to the install. I could not get the OEM lines off of the brass connectors where I spliced in the cooler so I left them on each end and put a small section of hose between. I maybe lost a half a cup of fluid and I warmed the system up drove it a bit and checked the fluid hot. It looked good and everything appeared fine. Later I drove it again and it started shifting funny and then would not shift out of 2nd. I quickly brought it home and am now baffled as to what has happened. I have a friend who told me there may be a check valve in the line at the radiator and maybe it is clogged. He recommended replacing the entire line. Has anyone had any experience replacing the lower transmission line? Any other ideas on what might be going on? I noticed where the OEM line goes into the radiator there is back and forth movement but no leaks. Looks like it is made this way but could I be pinching something by increasing the length of the OEM rubber section?

 

Just a thought; the transmission's ECU programming may have got used to the cooler running temps with the aux cooler connected, and now it thinks that the trans is running hot & puts it into limp mode? Maybe try disconnecting the battery for a few hours to reset the PCM.

 

Have you figured out what the problem is with your transmission?

I also have installed the B&M Racing transmission cooler. I originally had tons of leaking around varying spots, but now I've got the leaks under control. No sooner had the leaks finally stopped than the transmission starts stuttering from 1st to 2nd like it's low on fluid.

I'd be interested in finding out how you resolved this issue.

Thanks!

Micah

 

How long has your aux cooler been installed?
Did you install it in series with the OEM cooler?
How long since you checked the fluid level?

 

My auxiliary cooler was installed about 6 months ago. It's in series with the transmission lines and follows the walkthrough that's on the forums. I just fixed the leaking issues about 2-3 weeks ago, and it's been shifting hard pretty much since then. I've been checking the fluid regularly since it's been acting up to make sure that it's ok. I keep the engine running while checking.

Micah

 

Last night I removed the adapters that I had installed to go from the old tubing to the new tubing. I cut off the old rubber tubing adapters and flared the stock hard lines. I then rerouted new tubing straight from the old hard lines to the cooler. So far this morning, the transmission has been a lot smoother with the shifting. I think the adapters were disrupting the flow enough in this colder weather that it was causing the transmission to skip.

Micah

 

I also installed a B&M Cooler over a year ago. Jeep has been to Death Valley in the summer and Montana in the winter without any issues or Hot Oil warnings. You must have plumbed it wrong or one of the lines is crimpted.

Flash