2007 Q7 Towing capacity and upgrades - not factory towing package
 

I have a 2007 Q7 without the factory towing package. The towing capacity is 5,500 lbs and my understanding is that you can not get aftermarket packages to bring it up to 6,600 lbs.

Is this correct?

The reason is that I have a trailer that weighs 4,650 lbs, but after filling with water, propane, bikes, etc. it will probably be close to 5,500 lbs. I will be towing through the mountains in the summer. 2 questions.

1) Anything I can do to the transmission to protect it? My understanding is that a transmission cooler is not available.
2) Assuming I can not do anything on #1 above, am I OK to pull? ie. When Audi rates at 5,500, is that based on a flat road or could I tow 5,500 lbs through the mountains in the summer without blowing the transmission.

Any help on this would be appreciated as I have not been able to find a solid answer.