99 ECSB silverado 2500LD 4x4. Manual shift tcase, LQ4 6.0 with 4l80e. I haven't found a trustworthy GCWR rating, should be able to pick up a factory owners manual this weekend and see what was in there.
I'm likely swapping the 9.5" 3.73 rear for a 10.5" 4.10 rear I picked up, and on the fence about pulling out the front diff/tcase, swapping in 2wd 4l80e, and running 2wd full time. Tow guides for the 99/00/01 don't show a real big tow difference from LD to HD trucks that I have found but in later trucks it looks like the difference from the 9.5 to 10.5" rear along with likely stouter springs helped enough in cargo weight capacity to jack the fifth wheel trailer rating a good ~4000lbs over the 9.5" rear trucks.
I'd ASSumed the 1500HD trucks had the taller frame from the 2500HD and 3500 but seems some suggest that it's the same as my 2500 frame, in which case I could likely go off 1500HD numbers since the axle/spring package would be the other big difference between my truck and a 1500HD, and with swapping the axle if I also put airbags on it it's likely a wash.
I think I'll be operating in a good safe margin if I stay under the GCWR rating of a 4.10 geared 2500HD but really looks like a crap shoot on guessing what GM would have put the towing / 5th wheel towing capacity at if they'd have built a truck this way. Anyone want to guess?
I'm likely swapping the 9.5" 3.73 rear for a 10.5" 4.10 rear I picked up, and on the fence about pulling out the front diff/tcase, swapping in 2wd 4l80e, and running 2wd full time. Tow guides for the 99/00/01 don't show a real big tow difference from LD to HD trucks that I have found but in later trucks it looks like the difference from the 9.5 to 10.5" rear along with likely stouter springs helped enough in cargo weight capacity to jack the fifth wheel trailer rating a good ~4000lbs over the 9.5" rear trucks.
I'd ASSumed the 1500HD trucks had the taller frame from the 2500HD and 3500 but seems some suggest that it's the same as my 2500 frame, in which case I could likely go off 1500HD numbers since the axle/spring package would be the other big difference between my truck and a 1500HD, and with swapping the axle if I also put airbags on it it's likely a wash.
I think I'll be operating in a good safe margin if I stay under the GCWR rating of a 4.10 geared 2500HD but really looks like a crap shoot on guessing what GM would have put the towing / 5th wheel towing capacity at if they'd have built a truck this way. Anyone want to guess?