Transmission Heat Exchanger

[imbvl]

I use my 4.4 X5 to pull a boat, sometimes. Not a big boat, maybe 2300 lbs., boat, motor and trailer. (With 300 hp and full-time 4-wheel drive, I have no problem pulling the boat up a slimy ramp!) If it's a hot day (here in Florida) and a long trip, the transmission refuses to shift, and I end up going down the highway in 3rd gear at 3500 RPM. Other threads lead me to believe that the transmission heat exchanger is not doing its job, and the tranny oil is overheating. Is there a DIY thread on this problem? Can I just remove it, flush it out, and replace it? It's $350 for a new one.

I've ordered a BMW TIS on EBay, but it hasn't arrived yet. It's not apparent to me, what holds the cooler in place. Maybe the middle cylindrical thingee on the front side?

The tranny was replaced about two years ago, with a factory re-build, so I don't think it's a tranny problem.

I can obviously take it out, figure out the problem, take some pictures, and write a DIY thread myself, but I'd rather not invent the wheel, if I don't have to!

Thanks!

Bruce