GMC Sierra Towing
Question:
Hello all, perhaps some of you can offer advise on engine and axle ratio selection. I’m planning to buy a 2000 GMC Sierra 1500 SLE with 2WD, extended cab & short box. I will be towing a popup trailer initially but later on may upgrade to a larger trailer, so I want to make sure I have enough towing capability. The options available from GMC’s brochure are as follows: 4.8L V8, 3.42 axle = max. trailer weight of 6800 lb. 4.8L V8, 3.73 axle = max. trailer weight of 7800 lb. 5.3L V8, 3.42 axle = max. trailer weight of 7800 lb. 5.3L V8, 3.73 axle = max. trailer weight of 8800 lb. Obviously, the last option listed gives me the greatest towing capacity but I believe 7800 lb. will be all that I will need in future. Which engine should I buy? The 5.3L gives me more HP and Torque but would be less fuel-efficient and costs $1040 CDN more than the 4.8L I can still get 7800 lb. by going with the 4.8L and the 3.73 axle but I believe with the 3.73 axle, I’ll use more fuel than with the 3.42. Fuel economy is more important to me than spending the extra $1040 for the 5.3L. So what’s the best combination from both fuel point of view and from a trailer towing point of view. I expect to do towing in mountainous areas so pulling up steep grades would also be a factor. Thanks for any help you can provide. Clark .
Response:
>Hello all, perhaps some of you can offer advise on engine and axle ratio >selection. I’m planning to buy a 2000 GMC Sierra 1500 SLE with 2WD, extended >cab & short box. I will be towing a popup trailer initially but later on may >upgrade to a larger trailer, so I want to make sure I have enough towing >capability. The options available from GMC’s brochure are as follows: > 4.8L V8, 3.42 axle = max. trailer weight of 6800 lb. > 4.8L V8, 3.73 axle = max. trailer weight of 7800 lb. > 5.3L V8, 3.42 axle = max. trailer weight of 7800 lb. > 5.3L V8, 3.73 axle = max. trailer weight of 8800 lb.
Forget those figures for a moment. I’ve got a 99 silverado xcab 5.3/auto/3.42 locker and I do occationally tow with it and I wish that I’d gotten the 3.73 rear end. It definately has more grunt than the dodge ram that I traded in on it but I wish that I’d gotten a higher gear ratio. >Which engine should I buy? The 5.3L gives me more HP and Torque but would >be less fuel-efficient and costs $1040 CDN more than the 4.8L
You want the the most engine that you can get and the 5.3 is it. It offers you more low end torque than the 4.8. >I can still get 7800 lb. by going with the 4.8L and the 3.73 axle but I >believe with the 3.73 axle, I’ll use more fuel than with the 3.42.
The fuel penalty for the 5.3 is 1mpg less than the 4.8. Hardly worth mentioning with the increase in horsepower and TORQUE (what you need when to pull a trailer). >Fuel economy is more important to me than spending the extra $1040 for the >5.3L. So what’s the best combination from both fuel point of view and from a >trailer towing point of view. I expect to do towing in mountainous areas so >pulling up steep grades would also be a factor.
Steep grades? Sounds like you need a 2500 with the 6.0 and a 4.10 rear end.
Response:
Greg, thanks for the advice. This is exactly what I was after. – Hide quoted text — Show quoted text – >Forget those figures for a moment. I’ve got a 99 silverado xcab >5.3/auto/3.42 locker and I do occationally tow with it and I wish that >I’d gotten the 3.73 rear end. It definately has more grunt than the >dodge ram that I traded in on it but I wish that I’d gotten a higher >gear ratio. >Which engine should I buy? The 5.3L gives me more HP and Torque but would >be less fuel-efficient and costs $1040 CDN more than the 4.8L >You want the the most engine that you can get and the 5.3 is it. It >offers you more low end torque than the 4.8. >I can still get 7800 lb. by going with the 4.8L and the 3.73 axle but I >believe with the 3.73 axle, I’ll use more fuel than with the 3.42. >The fuel penalty for the 5.3 is 1mpg less than the 4.8. Hardly worth >mentioning with the increase in horsepower and TORQUE (what you need >when to pull a trailer). >Fuel economy is more important to me than spending the extra $1040 for the >5.3L. So what’s the best combination from both fuel point of view and from a >trailer towing point of view. I expect to do towing in mountainous areas so >pulling up steep grades would also be a factor. >Steep grades? Sounds like you need a 2500 with the 6.0 and a 4.10 >rear end.
Response:
Greg, just thought about something you said – you wish you had bought the 3.73 rear end. Why? What experiences have you had that makes you say that? – Hide quoted text — Show quoted text – >Forget those figures for a moment. I’ve got a 99 silverado xcab >5.3/auto/3.42 locker and I do occationally tow with it and I wish that >I’d gotten the 3.73 rear end. It definately has more grunt than the >dodge ram that I traded in on it but I wish that I’d gotten a higher >gear ratio.
Response:
>Greg, just thought about something you said – you wish you had bought the >3.73 rear end. Why? What experiences have you had that makes you say that?
The 3.73 is a better ratio for pulling than the 3.42. It gives the engine a better mechanical advantage than the lower ratio does. It’s like riding a 10 speed bike, the 4.10 is like starting in first, 3.73 like starting in second and the 3.42 is like starting out in 3rd. Which gear would you want to be in if you were starting up a hill? It’s easier for the engine to pull a load if the gear ratio is in it’s favor. I’ve pulled a 6×12 uhaul trailer and I definately felt the trailer when I left the light, it put a lot of resistance on the truck and I could feel it in the engine. Now I live in FL where it’s relatively flat and at sea level. If I would of had a higher ratio the engine would have gotten into it’s power band sooner and the trailer wouldn’t have seemed as heavy as it did with the engine operating at a lower rpm. Basically the larger the ratio is the quicker the engine will rev up which will provide you with more hp and torque to the wheels. Does this make sense? Now take into account how much power you loose per 1k of altitude and throw in some hills and you soon realize that you need some serious torque and hp in the first place. I didn’t buy my truck to haul trailers on a regular basis but if I’d had that in mind I surely would have a 4.10 rear end on it.
Response:
Thanks again Greg, excellent explanation. Makes good sense to me now. – Hide quoted text — Show quoted text – >The 3.73 is a better ratio<snip>
Response:
Usually one should buy the RV first and then the tow vehicle. I however didn’t do that. I ordered a ‘92 Chev C-2500 Silverado with the 5.7, auto, 3:73, etc. I tow a 25′ fifth wheel and it does real well. Jim P.S. Go with the most. It beats trading in again. – Hide quoted text — Show quoted text – > Hello all, perhaps some of you can offer advise on engine and axle ratio > selection. I’m planning to buy a 2000 GMC Sierra 1500 SLE with 2WD, extended > cab & short box. I will be towing a popup trailer initially but later on may > upgrade to a larger trailer, so I want to make sure I have enough towing > capability. The options available from GMC’s brochure are as follows: > 4.8L V8, 3.42 axle = max. trailer weight of 6800 lb. > 4.8L V8, 3.73 axle = max. trailer weight of 7800 lb. > 5.3L V8, 3.42 axle = max. trailer weight of 7800 lb. > 5.3L V8, 3.73 axle = max. trailer weight of 8800 lb. > Obviously, the last option listed gives me the greatest towing capacity but > I believe 7800 lb. will be all that I will need in future. > Which engine should I buy? The 5.3L gives me more HP and Torque but would > be less fuel-efficient and costs $1040 CDN more than the 4.8L > I can still get 7800 lb. by going with the 4.8L and the 3.73 axle but I > believe with the 3.73 axle, I’ll use more fuel than with the 3.42. > Fuel economy is more important to me than spending the extra $1040 for the > 5.3L. So what’s the best combination from both fuel point of view and from a > trailer towing point of view. I expect to do towing in mountainous areas so > pulling up steep grades would also be a factor. > Thanks for any help you can provide. > Clark > .
