1995 Burb power when towing problem

Son has: 1995 chevy suburban 2500 6.5 turbo diesel with 3.73 rear end.
When towing his boat uphills the Burb slows down to 25-30 mph. It seems he has replaced or has had everything inspected but nobody seems to know what is causing this to occur. My suspect from looking at the forum is he needs to go back to large tires, and get a 4-11 rear-end to start, maybe check the fuel filter & Pump.
Additional comments or sugestions would be good.
Ken

Ken

How many miles on it? What size tire do you have with the 3:73 rear?

First things to check are the air & fuel filters. Do you have a boost gauge? Boost(or lack of) may be your problem, and their are a few reasons why this could be happening. Do you hear the lift pump at all?

Is the exhaust original? Do you still have the catalytic converter in place? A high mileage 6.5 is known to clog these up. Remove or Gut the cat. It has no place on a diesel.

Post more info...

Son has: 1995 chevy suburban 2500 6.5 turbo diesel with 3.73 rear end.
When towing his boat uphills the Burb slows down to 25-30 mph. It seems he has replaced or has had everything inspected but nobody seems to know what is causing this to occur. My suspect from looking at the forum is he needs to go back to large tires, and get a 4-11 rear-end to start, maybe check the fuel filter & Pump.
Additional comments or sugestions would be good.
Ken
Seems son has determined it was the fuel filter, so he is having it replaced with a marine one, cleaning the tank and getting GOOOOOD fuel...Thanks for all the support, and if this does NOT resolve the issue we will be back ...
Ken