When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
just got back from a little trip.went and hauled a sweeper truck from lincoln neb. to s.l.c. ut. went through the scales and had 11,200lbs on the trailer and 1800 in the bed of the truck and was able to do 70mph no problem and 65 on the hills!
With your setup 70mph should put you right around 1700-1800rpm in 6th gear--right at the peak of the torque curve. It was probably happy to tow all that. Do you still have the stock clutch in there? How did it handle the load?