Big thing to look at is if it’s symmetrical or asymmetric for the lift arms. My former techs have lifted one ton trucks on an 9k asymmetric lift and generally it works but if they had stuff in the bed it did have a tendency to cause the rear (longer) arms to sag. Worst case happened when the lift picked a dually up but the sag was so much the locks bound up and we couldn’t get it down.
I warned them not to do it and yet it happend. We ended up supporting the rear with a pair of one-man pole jacks, lower the lift to the next lock, lower the jacks, repeat. After that it was clearly marked that 1tons were not to be lifted on the 9k lifts. We had a 12k symmetrical lift to raise the big stuff or our 15k alignment 4post rack.
It comes down to even though a lift is rated for “x” and the truck is under that value it still depends on the truck as to if it’s safe to lift. A 2015 3500hd dually has a curb weight between 6000-8000 pounds depending on the options. Technically you could lift one with a 8k lift. If it’s asymmetrical I wouldn’t. If would still be pushing it with a symmetrical lift.
I know it’s obvious to say, but for something you will be working underneath be smart, don’t max out the lift capacity to save time. It may not break the first time, but continued overloading will fatigue parts and will fail on you. Maybe with you under it.
Minutes saved out of convenience is not worth loosing anybody to a failure. Nobody wants to have their wife or SO come into the garage and find you crushed under a truck when the lift failed.
