LCAC_Man - thank you very much for the information. I will reach out to Advanced and see what they say about the gearing.

 

I'm not big on telling people what to do...but...if I were towing 9000lbs for extended distances I would be running 4.30 gears. I'm installing 4.30's on mine, the max I'll be towing is 7000lbs and that will only be short runs. I am going to be on 34" tires (285/75/17) and with the hightop and when the interior build out is done the van will weigh 8700-ish..
The Duramax is fine at 7500lbs and 1700rpms in 6th gear but when you double the weight you'll find it is the most efficient closer to 2100rpms and your trans will stay cooler.

 

Phase I upgrades.

 

Nice.

 

Has anyone purchased the swivel bases from Discount Van-Truck? chevy van seat bases,driver,swivel seat bases. If yes, how was the install and function? Thanks.