Gear Ratio Query

[Fishhawk]

I have a 2010 GMC gas 2500 4WD with a 6.0 and 3.73 ratio
Pulling my 6800 lb camper, the engine labors a bit on these Arkansas hills
Now I'm upgrading to a bigger camper , 8500 lbs
and contemplating changing the gear ratio from 3.73 to 4.10

I'll check next week for gear change out costs locally, but would appreciate any input concerning what reasonable pricing to do this should be
and any enhanced performance results

Thanks

Hawk

[hankpage]

Any answers you get will depend on location. Labor rates vary considerably in different parts of the country. Some areas may be double the cost of others so replacing the entire rear with a salvaged one may be cheaper. (less labor and you can sell your old parts and recoup some of the cost) JM2¢, Hank

[Ken / Claudia]

Some of your question can be found in the manual. Look up up the tow rating for each rear end as applied to your truck. It should show tow ratings for different engines, transmissions and rear ends in the same 2500. My opinion is only that, the 4:10 will tow heavier loads better and get less mpg than the 3:73 in a gas engine. Cost ? I have switched out complete rear ends in 2 trucks, not that diffiult, I got junk yard used rear ends. I needed help do to the weight and size of what your moving around.

[rooti]

To actually answer your question...It depends if you go GM or aftermarket. If your truck was available as an option for the 4.10 gears then GM could do it and they would be able to reflash your ECM for the new gears. If it wasn't an available option you would have to buy a programmer or find a dyno tune shop that could change the ECM to accept the new gears. If you don't reflash it then the shift points might not be right and it may throw some codes.

In my case, with my 1/2 ton, even the 3.73 gm gears would not fit in my stock differential so I am forced to go with aftermarket. The cost will be about 600 for parts and labor plus another 150 for a reflash but I am going with a tuner instead to get a little more out of the engine. So I'll be at about 1000 bucks total. GM will not do the work since it is not factory parts so I'm going with 4.11 gears from yukon.

I doubt if you will lose any gas mileage and if you get a tuner you will probably even see an increase.

Gear change is not easy as everything has to be precise so find a good shop to do it. The shop that will be doing mine suggest a 500 mile break in before towing and they inspect and replace gear oil at that time

[Ken / Claudia]

rooti, has a good point that I did not think of at all since I was working rear end changes before the computer age. Changing out rear ends is more than bolting on new parts with computers everywhere. I guess I would be talking to a shop.

[gearhead]

I'm pretty sure the truck was available with 4.10. I would talk to a GM dealer and price them against a small shop. Just be sure the small shop takes care of re flashing the computer and everything the GM shop does. GM would have the advantage of warranty if you have issues on the road away from home..

[Fishhawk]

Good info

Thanks to all!!

I'll check with some shops next week

Hawk

[JRTJH]

Something you probably consider "obvious" but hasn't been stated in this thread... Your truck is a 4WD, so you will need to change out the front axle gearing as well as the back axle. I'm sure you already knew that, but it wasn't on the table that I could see.

Good Luck

[RGene7001]

I would not do any changes until I know for sure they are necessary. There is nothing wrong with higher rpms on hills, a gasser just needs to spin and breathe in order to make power. I would be concerned only if rpms fall outside the engine's "sweet spot" where power/torque output is maximal. In my case the optimal range is 2400 to 5000 rpms with redline @ 6600 rpms. With 5800 lb behind my tach reads 3000 @ 65 mph on level surface and 4000 rpms on topical interstate grade. No problems after several cross country trips

[audio1der]

My reading reveals a 3500-5000lb(depending where you read) towing advantage for the 4.10s over 3.73s, with a real world 0.5MPG drop. That seems VERY worthwhile to me, even if your door placard/GCVW will never show that extra capability.
The 4x4 requiring the front axle gear change does add to the cost, but if you're using the truck for towing unless the cost is outraheous, it should keep you ahead of a trade-in to get the gears you need.

[bsmith0404]

I had a 2002 GMC 2500 HD with the 6.0 and 4:10. It pulled my 8,500 lb 5er pretty good until I started across the mountain passes out in Colorado and Wyoming. I've never had the 6.0 and 3:73 combination to compare to. I have pulled through the AR hills with my Dmax. I would make a guess that you would be happier with the 4:10s, but I wouldn't expect night and day difference like changing to a diesel.

[Brantlaker]

If you go to this web site it has all the towing specs form GM.
http://www.newgmcsierra.com/images/n...ring-Guide.pdf.
Yes there was a 4:10 gear that year and the Diff housing front and rear are the same with 3:73 or 4:10