Will I regret the 4:10 rear

SWDoodle · April 18, 2013

We just ordered a new 5th wheel camper that is 8500 lbs dry and has a gross weight of close to 12000 lbs. I'm looking to pull the trigger on a new 2500HD gasser and am trying to decide on which rear ratio to go with. I think the 3:73 is under rated but not sure I want to go with the 4:10. I won't ever have it to the full 12000 lbs. Anyone with experience with both configurations? How much difference will there be on fuel mileage?

You will be close to 18,0000 GCVW with that setup. You will regret not getting the 4.10. Unless you were driving lots of highway miles in a flat area (like I live in) the mileage will be neglible. There won't be much difference in mileage in real world driving/towing over the 3.73. The rpm cruising at 65 mph may be a few hundred more. In a big vehicle such as a 2500HD that's not an issue. Plus what I like about having a lower rear end is that you won't downshift quite as much which over the long-term which will help conserve tranny life. In a gasser with low torque (relative to the duramax) you want the lowest rear end you can get. The duramax doesn't need the 4.10 because it creates twice the torque the 6.0L does. Plus, since most salesmen are dumb enough to think the 3.73 will gain you significant mileage on an HD pickup, they hardly ever stock any. It is rare to find a late model 6.0 with the 4.10. It will be more valuable to the right person in my opinion when you go to trade it in. You made the right choice. Now the 3.73 is more than adequate, but the 4.10 is just better. Just my $0.02.

crazydog · April 24, 2013

No, you won`t regret it. Difference in gas is not noticeable and you`ll regret NOT having the tow capacity if you need it! All of my trucks have had the 4.10. The 2010, the dealer had to ship from a lot in Quebec for me as he couldn`t find the 4.10``s here (ON). The 2013 was a factory order because the only 2012`s he could find me had the 3.73. I`ll probably never max out the truck`s towing capabilities, but at least I know I have it if I need it one day . .. .

C/K Man · April 25, 2013

I have a 2012 3500HD 6.0L/6L90/4:10, and it is a great combination. As the earlier poster pointed out, with 2 overdrive gears there really isn't a penalty with 4:10's. 3500's SRW's come with 18" wheels too, so with a tall rim and tire there is not a point to running 3:73's unless the truck is Duramax powered.

BogeyHD · May 3, 2013

Well I couldn't find exactly what I wanted in a 2013 with the 4:10, so I have found a 2011 with 19k miles and all the options I wanted and then some. My dealer is going to bring it in from the US and should get it next week. Thanks for all the replies. Can't wait to get it and hook onto the new trailer and try this thing out.

chipjumper · May 3, 2013

What are the RPM's at 65MPH with a 4.10? I have a '01 3.73 Suburban 2500 4L80E and I'm at 2000RPMS. I wonder how much of a difference I would get with 235/85R16's vs OEM. Maybe I should upgrade and get the six speed tranny if I'm so whiney about the MPG's...

brainpause · May 3, 2013

What are the RPM's at 65MPH with a 4.10? I have a '01 3.73 Suburban 2500 4L80E and I'm at 2000RPMS. I wonder how much of a difference I would get with 235/85R16's vs OEM. Maybe I should upgrade and get the six speed tranny if I'm so whiney about the MPG's...

all things being equal, except for the gear set, the RPM's will be 10 percent higher from 3.73 to 4.10.

Ramin258 · May 15, 2013

4.10 is definitely the way to go. I have a 2011 GMC 3500HD 4x4 with the 6.0 gas motor and 4.10 gears. Combination driving I average 13-14 MPG, City driving I get 12 mpg and highway I get 15-16mpg. I pull a fifth wheel that weighs about 7000lbs and get 8mpg. The 4.10 rear will also be better for your transmission.

MisterC190 · May 15, 2013

I run 4.10's on my 1500.. I also get 12-14mpg w 35's, headers, muffler, and a tune..

I definitely do not regret it... Much more responsive.. It's a different truck altogether now..

Make sure you tune afterward so your speedo is right.. The tune ties all your mods together..

MikeNH · May 15, 2013

I run 4.10's on my 1500.. I also get 12-14mpg w 35's, headers, muffler, and a tune.. I definitely do not regret it... Much more responsive.. It's a different truck altogether now.. Make sure you tune afterward so your speedo is right.. The tune ties all your mods together..

The HDs can have 4.10s stock, no need for speedo correction.

yukon25008.1 · May 15, 2013

I would go 4;10 and 4;10 only.. you will tow better, And if you decide to go with a slighly taller tire you,ll be ok.

sdeeter19555 · May 16, 2013

Another option is to buy the truck of your liking and then swap gears...migh be cheaper than paying to get one shipped in.

If I towed more frequently, I would have bought 4.10s. If I ever decide I need it, I will bypass 4.10s and look at something like 4.56s. As noted, the double OD seems to have plenty of gearing to make up for the lack of rear gearing.