New guy with rear end question

**ruachevyman** · 09-10-2008, 09:48 PM

Hello everyone, Im a newbie and have a question. I own a 2001 Chevy Silverado 1500HD Crew Cab (4 full doors) 6.0L gas 2x4 6.5 foot bed. I pull a fifth wheel camper and would like to get a little more pulling start off power with a new set of rear end gears. I currently have 3:73 and would like to install 4:10's. To me the rear end stuff looks a little confusing online. Can anyone advise on where to shop and what to buy, model number, item number, just need to know what to order.......? Would this have any other negative effects on the truck other than gas mileage. I saw that rear end upgrade was a option that could have been installed from the factory back in the day. Thanks

**retired2001** · 09-10-2008, 10:25 PM

I tried to buy a truck like yours back in '01. The reason I didn't was that I was told that the gears were 4:10s from the factory and I didn't need that low of a gear or gas mpg. I'm sure someone "in the know" will give you some help before long.

**collinsperformance** · 09-11-2008, 01:51 AM

which transmission do you have? what size tires?? you might find 4:56 are better.....mike

**ruachevyman** · 09-11-2008, 06:57 AM

Originally Posted by collinsperformance

which transmission do you have? what size tires?? you might find 4:56 are better.....mike

265/75/16 and the 4L80E tranny

**95CTburb19** · 09-11-2008, 02:52 PM

I dont think you would want 4.56. you will get terrible gas milage. I have 4.10's in my 5.7 sierra and got 10-12 mpg's but it was pretty torque -y. I would not do gears myself, it's pretty easy to screw em up. Personally I wish I had 3.73's.

**collinsperformance** · 09-11-2008, 07:56 PM

i say it is not cost worthy for a swap from 3:73-4:10 with the auto tranny I go with the 4:56 and be happy. the pulling power would be way better and not too bad a MPG loss. the overdrive will keep the milage up some as well.i send my gear swaps out since i not done one and do not have the tools to do one...mike

**ruachevyman** · 09-11-2008, 10:00 PM

Right now pulling my fifth wheel, Im at 2,000 RPM's at 63MPH. If I went with 4:10, I will be in the range of 2,200 RPM's a 10% increase. If I went with 4:53, I would be around 2,400 RPM's pulling at 63MPH a 20% increase. I think 4:56 would kill my gas mileage. Right now I'm getting 9-10MPG pulling the camper. 200 miles to one tank of gas pulling the camper

**collinsperformance** · 09-12-2008, 11:51 PM

might get a set of taller tires and and 4:56 or stay with what you got and go smmall profile tires......I getting 17 with 4:56 and 40"X17" tires on my bronco. mike

**tbplus10** · 09-13-2008, 11:34 AM

With the 6.0 4.10's would be the best choice, 4.56's will destroy fuel mileage, I experienced setting up an 03 Suburban with 4.56's that were r&r'd a few weeks later because unloaded the truck was getting 8-10 mpg. The 6LTR engine has lots of torque and shouldnt have a problem pulling long or steep grades with 4.10's while maintaining acceptable mileage in town.
We pulled a 2800lb 36ft trailer with 2 crawlers, tools, and spare parts for a total weight of 11000lbs through Colorado and had no problems.
4.56's at cruising speed place the engine RPM's in an area where mileage gets real bad. We crunched all the numbers prior to swapping gears and thought we new exactly where this truck would run with the new gears. We were way off base, the performance increase was minimal and mileage was nothing near where we calculated. The 6.0 has a fine line on the RPM band where it goes from acceptable mileage/performance to acceptable performance/terrible mileage.
Be careful of modifications to this engine package the computer is finicky about performance enhancements (mechanical and computer) and doesnt always react well or as expected. The Suburban I worked on has had a lot of modifications done to it, many were done to remove or counteract mods previously done to the truck.