Here is the post...
IMNSHO
, you've been over zealous in locking down the towing thread.
The answer for the OP is: Due to liability reasons, therangerstation will not endorse exceeding manufacturer limits for GCWR/GVWR.
As noted from other posts, Ford's limit for 2.9/manual/4x4 would be <3,400 lbs. (limit for the '91 4.0/manual/4x4, which was the best I could find online - Ford's brochure) as 2.9 makes less power*.
The empty weight of the dolly is ~750 lbs. per U-Haul's site.
The OP has reduced his maximum by installing larger than stock tires (they add weight).
Driver, anything else in cab/box, any options, etc. count against the limit - which is why SAE came up with J2807 - manufacturers, now need to include driver (but only of 150 lbs., any options found in 30% of production - e.g. A/C, power windows, etc.) So, the limit is now at least possible vs the pre-J2807 spec, i.e. '88 limit, which you had to deduct at least a couple hundred pounds from.
So, the limit would be <2,500lbs for legal purposes based on OP's information, which is why we won't endorse towing 3,300 lbs. on the forum.
Now, the reason for my issue with locking down the thread:
U-Haul and all the other vendors which I have rented from HAVE surge brakes in their dolly's. I wanted to correct our colleague's incorrect entries (There's enough misinformation on web, therangerstation doesn't need to add to it).
In many places, trailers over 1,500lbs/>40% of towing vehicle weight require trailer brakes and to have equipment which wouldn't be legal would put U-Haul (or other renter) in bad place for liability. So, it is prudent for a company renting trailers (dolly being just a very specific type of trailer) to put some kind of braking on all trailers which would exceed that limit.
Companies renting trailers historically renting trailers needed to use surge brakes as one couldn't count on towing vehicle having wiring for electric brakes. Because of the use of surge brakes, it means the trailer can't be backed up - huge PIA when you want to maneuver the trailer into its final location.
My 2 bits to start 2021 off with.
Now for the Tech Library article...
Towing Trailers – The Ranger Station