Our van has the 5.7L (and I think different transmission) and 4.10 rear; our experience won’t be the same as with your van. Our trailer runs 6-7k loaded (5400 unloaded) and our cargo van weighs less and has less added payload than a typical passenger van with passengers.
It tows well on the flat, we struggle to stay at the posted speed limit on the uphills of I81 through PA. I have found tires make a difference in stability while towing; I have found the Michelins we’ve had provided the best stability.
Note: Extended GM vans have longer wheelbases than regular length vans (the rear overhang is the same) unlike Ford E vans.
Mark & Renee
Working Border Collies: Nell (retired), Tally (retired), Grant (semi retired), Lee, Fern & Hattie
Duke & Penny (Anatolians) home guarding the flock
2001 Chevy Express 2500 Cargo (rolling kennel)
2007 Nash 22M