Gearing question.

Tinbender · 11-29-2013, 05:23 PM

Hi all,
I am presently towing my Cougar 24RKS (under 7K loaded) with my 06' 1500
GMC. 5.3, 4 speed auto and a 4:10 rear end.

Want to move up to a 2013 2500 with the 6.0 and six speed auto trans. Should I stay with the 4:10 rear end or go with the 3:73 gearing?
Thanks for advice and opinions.
Tinbender

concours · 11-29-2013, 05:48 PM

4:10 all the way with the trans that you have you will probably see better fuel mileage as the trans will stay in the higher gears even when not towing, Trust me I spent many years as a GM service tech and Manager

therink · 11-29-2013, 06:05 PM

X2- 4:10 all the way. Gives you almost 4k more towing capacity and fuel mileage difference is negligible. You will likely have to factory order to get 4:10. Dealer stock is almost always 3:73 with the 6.0 gasser.

Bob Landry · 11-30-2013, 06:31 AM

I went from a Tundra 5.7L/4:30 to a F250 6.2L/3.73. HP & torque is almost identical with the two engines, and I have not noticed any appreciable difference in towing performance, or fuel consumption. The 6 speed trannies seem to have really made a big difference in towing capabilities on all of the trucks.

Jim W · 11-30-2013, 07:23 AM

You are staying with the gas engine correct? Then you can get the 4:10 differential with the 6 spd auto. If you decide to go with a Diesel engine I believe the only differential you can get is the 3:73 from what I could figure out on the order site for Chevy/GMC.

It seems that all the big three are only offering one gear ratio for a SRW diesel engine trucks. You can thank the government CAFE rules.

I myself prefer to pull with a diesel engine equipped truck. One; the torque of a diesel for pulling cannot be matched by a gas engine truck. Two; the ease of filling the truck/trailer combo with fuel is far easier with a diesel engine, than gas engine truck. I know I have pulled with both. Three; there is less engine noise since you are in a lower RPM range with a diesel engine. I am tow around 1,800RPM at 65 MPH in 6th gear.

Just my $0.02

Jim W.

**JRTJH** · 11-30-2013, 07:52 AM

Quote:

Originally Posted by Jim W

... It seems that all the big three are only offering one gear ratio for a SRW diesel engine trucks. You can thank the government CAFE rules....

Jim W.

Ford offers two differential choices in the F250. 3.31 and 3.55.

Tinbender · 11-30-2013, 04:52 PM

Thanks for the input guys,

I will be staying with the gas engine, (6.0) but moving up to the 3/4 ton size. I am trying to figure out if there is any appreciable difference in low end torque and the towing/unloaded gas mileage comparing the 3.73 and the 4:10 rear end gearing. Both rear end gear ratios are available to me either in the GMC or the Chevy, and of course they both have the 6-speed.
Not being familiar with the 6-speed I am thinking that it should negate the differences between the two rear ends on both the upper and lower ends.

Any further help would be appreciated, I will probably close the deal the first of the week.
Thanks
Rick

therink · 11-30-2013, 05:12 PM

I really don't know performance wise if there is a noticeable difference between the two, as all I have owned is 4:10. The reason I chose 4:10 was because the tow rating is around 14,000 versus around 9,500 with the 3:73. If you are ever going to tow more than 9,500 lb trailer, then the 4:10 is what you will need to be within the GM specs for the truck.
All I can say is that the 4:10 6.0 combo handles my 12k fiver without issue.
If your dealer has both axle ratio trucks on his lot, maybe you can drive both and see for yourself.

Steve

Wayne · 12-01-2013, 06:59 AM

I did have an 08' GMC CC 6.0 w/373. It was a great truck & the 373 handled our 10K 5er fine. If the truck will be your every day driver; the 373 will give better mileage & pull your Camper fine. If you do not use the truck daily the 410 gives more tow capability & about the same mileage as the 373 when towing. If I purchased another gasser for towing; I would go with the 410 for both reasons previously stated. Good luck with your new truck.

I would also go with a SRW 1 ton....just in case I wanted a bigger 5er.

SmittysRV · 04-11-2014, 07:56 PM

I have 4.88s in my 06 F550 and it pulls like a champ!

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bsmith0404 · 04-12-2014, 02:44 AM

I would say it depends on where you tow. I used to pull a 9k lb 5er with a 2500 GMC 6.0, 3.73. It was fine on flat roads, hit the hills and it was constantly down shifting, hit the mountains and it was working hard. Seemed like one gear was to low, but the next too high. I was either running high RMPs or limping along at 25 mph going over mountain passes. The fuel mileage was 8 mpg, so I never passed a gas station. You will get about the same mileage with the 4.10s, but I would hope that you could gain enough power to stay 1 gear higher than I could. All of that is the reason I now have a Duramax, I will never go back. My dad and I both have the Duramax, my brother in-law still has the 6.0 gas. When we all go out together we just pull over and wait for him from time to time. When he needs to gas up, we top off our tanks too, just for the heck of it

PARAPTOR · 04-12-2014, 07:24 AM

Quote:

Originally Posted by SmittysRV

I have 4.88s in my 06 F550 and it pulls like a champ!

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Heap that is what you need to pull that house

down the road.

SmittysRV · 04-12-2014, 07:31 AM

Yes. This 5er is heavy! The F550 does carry 110 gallons so stoping for fuel is never an issue. The bummer with this truck is when not towing it doesn't make a good freeway cruiser as the 4.88s keep me around 65-70 and people are flying by me... I have thought about Gear Vendors as this thing actually rides better than my ol 02 F30 cc lb.

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