Towing advice to protect the transmission for xDrive35i?

[RhythmMachine]

We had a diesel MB to tow our small camper (about 2500 lbs dry) and it was either spectacularly easy or in limp mode. Car got totaled, and we replaced it with a 2012 X5 but, due to the issues related to diesel emissions systems, went with gas instead. I'll be installing a hitch with the BMW wiring harness/trailer module and coding that in later this month, have a weight distribution hitch to hook it up to the trailer, and I'll be adding a brake controller and have towing mirrors. The trailer is very well behaved to pull... short, which can make backing up go off the rails in a hurry, but I'm very familiar with towing it for the past 4 years or so.

The one thing I do worry about is the transmission... the 3L diesel had almost 400 lb-ft at 1600 RPM, so it could take on some pretty significant climbs by just spinning up the turbo and rarely had to downshift, even though it had a 7-speed transmission. The X5 has 300 lb-ft at a comfy 1300 RPM, but even when driving without a trailer I notice it shifting WAY more then the MB on the same roads/same driving style. Combine that with the 8-speed transmission, and I'm not sure how to best handle it.

I realize that towing will always cause more wear and tear on the transmission, but any advice on how to minimize it? Drop it into manual mode and use that to keep it from hunting on hills (we live near the rockies, so hills are going to be a regular occurrence)? The diesel provided excellent engine braking going downhill as well, and I'm not sure if that will still be the case or if I may need to rely on the brakes a bit more.




Love to hear about any experience you've had. Thanks!





UPDATE: quick summary of what I've learned along the way:
1. Use Sport mode when towing to reduce the number of shifts and wear on the transmission
2. Use M6 when towing to lock in the torque converter and lower transmission temperature, trading off a bit of fuel efficiency for what should be a longer-lasting transmission
3. Get the Dinan Stage 2 Tune software to both improve towing fuel economy and greatly increase the capability of staying in M6 while towing up more significant hills