89 Chevy 3500 Dually question

[Texas Red]

Just picked one up from a friend for a song. Has a 454 TBI, 3-speed manual w/granny gear and a 4.11 rear axle [2wd]. Tire size is 235/85 R 16. The door sticker is toast and I was wondering if anyone knows the maximum towing capacity of the truck? I've searched all over the web and can't find a definitive source for the info. If anyone knows of a specific site where I can find it, please let me know.

 

Thanks, Kelly

[Logan Lanfear]

Proably in the low teens.  Maybe 13000 pounds.  Could even be 10,000 pounds.   Hard to know without knowing the rest of the trucks options.  

[Texas Red]

It's got huge helpers on it, power steering, power disc brakes, trailer package with dealer bumper hutch, Gooseneck in bed, 2 bumper hitches in back [really big double decker 3/8" steel plate one]. I am really after the maximum factory number so I can add in the gooseneck and helpers on my own to come up with a maximum. No other load based options on the truck.