so I just bought this smoking clean 1 owner 1988 crew duelly with a 7.5 and c6 with 56000 original miles but it had a smoked 2nd gear the band actuator was stuck and burnt the band clean down to shiny metal..
the truck was always parked in his barn and only used to tow his horse trailer from time to time hence the low millage..
he had all the smogs and registrations since new to verify the millage and the truck looks new inside and out.. so I pulled the tranny and ordered a master rebuild kit with alto green clutchs and Kolene disks and replaced every o-ring, seal, gasket, bushing, 2nd gear band, 2nd gear servo (P) stamped on it, rebuilt the valve body and did the shift correction kit, repacked low/reverse with 6 clutchs and disks, and 4 in both the 2nd and drive packs... I set the vacume shift screw about half so she shift at 2500 under light foot 3500 under 1/2 pedal and around 4000 under heavy foot.. and she hooks up like a freight train and shifts firm and strong.. with the 460 and fresh tranny under her and a axle code of D5 which I believe is 4.10's .. what is the maximum weight I can tow trailer and load.. I am buying a 35' cabin cruiser that weighs 11000 without the 3000lb trailer so combined is 14000 plus fuel,water,and supplies will total around 16,000lbs plus the weight of the truck 5000lbs. so total should be around 21000 give or take a few lbs... it is 11 feet wide so I will be running oversize banners on the back of the boat and will only be pulling her about 40-50 miles each way most of the time... I have a cdl and pull double/triples and anything else you can put on the road so I am not worried about moving the mass just want to be sure the truck is up to that kind of load... I have heard many different stories and weights about what this truck can do but no verified numbers.. any help would be appreciated...

 

21000 is pretty much nearing the limit of the NEW F-350, so I would say that it's far above the limit of yours. You really need to consider this carefully, 40/50 miles isn't a short distance towing an oversized load.

 

Owners manual will tell you

my 95 manual says

a crewcab f350 dually with a auto and 4.10s has a gcwr of 18,500

but 88 may be different and especially if you have 3.55 gears