2012 Differential.

[AH64ID]

Vaughn,



No, not exactly. The Ram 2500s had LT265/85/R16 but the 3500s had LT235/85/R16s. GMs had LT245/75/R16s/

2500's had 265/75/16's.

 

[Barbieri]

If I change the tires I would change the front and rear of my trailer. That would require a possible change in the hitch bar. Thanks for the info.

 

[kcook]

I have the 2011 HO Laramie Longhorn with 3. 73, it turns such low RPMs in 6th gear I wish I would have gotten the 4. 10 and the higher tow rating with all the max tow stuff... Just couldn't pass up 13. 5K off sticker on the truck I got...

 

[RonD]

My 2012 Has 4:10, at 70 mph it turns about 1900 RPM's

 

[Barbieri]

Sorry but I don't understand what your trying to say. If in 6th with low RPM's that is what you should be getting. Going up a mountain in 6th is wrong and you should of dropped out of overdrive. That is what I have done with my 98. 5. As I understand it the 4. 10 is low end torque. I think you got a good deal. You might need to adjust your driving habits on shifting with the auto. Have a nice day.

 

[kcook]

Look at the difference in tow rating from each gear ratio for the Laramie CC DRW Long bed:



3. 42 - GCWR 17,000lbs, Max trailer 8,950lbs

3. 73 - GCWR 21,000lbs, Max Trailer 12,950lbs

4. 10 - GCWR 27,900lbs, Max Trailer 19,450lbs



That's a significant increase even from the 3. 73 to the 4. 10.

 

[kcook]

Sorry but I don't understand what your trying to say. If in 6th with low RPM's that is what you should be getting. Going up a mountain in 6th is wrong and you should of dropped out of overdrive. That is what I have done with my 98. 5. As I understand it the 4. 10 is low end torque. I think you got a good deal. You might need to adjust your driving habits on shifting with the auto. Have a nice day.

I can down shift while up to speed but then I loose gears "capability" Getting the load moving is where you really notice the difference and acceleration, that's where the drive train takes the beating especially the transmission... It's tough to keep the EGT's down pulling the higher gears also... Mostly wanted the significant increase in tow rating "nice to be on the right side of the law" especially if there's an accident...

 

[kcook]

Sorry but I don't understand what your trying to say. If in 6th with low RPM's that is what you should be getting. Going up a mountain in 6th is wrong and you should of dropped out of overdrive. That is what I have done with my 98. 5. As I understand it the 4. 10 is low end torque. I think you got a good deal. You might need to adjust your driving habits on shifting with the auto. Have a nice day.

Doesn't sound like you tow much, but 9,000lbs is Max for trailer weight for a 3. 42 geared truck, the 4. 10 option is not alot of money and you don't loose really anything fuel mileage wise so seems like a no-brainer...



You can do a real world test get on your mountain bike or 10 speed what ever you can get. Go for a ride and start in the first gear and shift normally through the gears start at the bottom of some good hills "you said you tow in BC and Canada right?" So make it some steep hills Canada especially BC has some real steep stuff... The do the same route only start in 4th or 5th gear let us know what you find out :-laf



Then let us know if you agree with the Engineers that the 4. 10 ratio will really handle 11,000 more lbs. of trailer weight than the 3. 42.



Wow BC I live in WA and have traveled through the BC Rockies a few times it's awesome but talk about hills... You will enjoy the exhaust brake on the 2011, I got one on my 2002 the week after my first trip through that area some of the long steep hills I came down had 90 degree corners at the bottom, that will raise the hair on your back a little if your towing much weight...

 

[Barbieri]

Well I only have a 9000 lbs trailer. So the 3. 73 would be just right. I don't expect to exceed the rating for the 3. 73 at any time. Thanks for the info. Like they say. Make sure you know the towing weight before buying the vehicle. In this case I know my weight. Have a nice day.

 

[WStephens]

Going from the 2005 2500 with the G56 and the 3. 73 and doing light to heavy towing with it and watching my gauges, I really suprised at how low the rpms are with 2012 3500 dually with the 4. 10 gears and the 68RFE transmission. I just made a round trip from eastern PA to WY and back it took me a while to get use to how low the rpms were. You really cant compair the two trucks because they operate so different. The new truck just works so much better.

 

[RustyJC]

With the double overdrives of the 68RFE, 4. 10s are painless. 1612 RPM @ 60 MPH in 6th. As far as I'm concerned, it's a no brainer.

Rusty

 

[Wingate]

With the double overdrives of the 68RFE, 4. 10s are painless. 1612 RPM @ 60 MPH in 6th. As far as I'm concerned, it's a no brainer.

Rusty

What he said!!...
3:42 gears are for pulling grocery carts... with the advantage of the 6 sp. auto I would go with the highest numerical gear I could get. 4:10... . If it were possible, I would go as high as a 4:56... but they do not currently offer that except with the gas engine.

 

[RVTRKN]

Thats incorrect, it is possible to have an 05 with the NV5600, then Dodge stopped installing the NV5600 mid year, and started installing the G56. They put a hold on the G56 for a couple of months for quality issues. Later in the 05 MY they restarted production with the G56, and it was with the different gearing. I don't know when the AD was changed to AE with taller gears, but it did.

 

[RVTRKN]

An '05 had the early G-56 with low gearing and low overdrive ratio. 3. 73 gears were a decent choice for that transmission, not for the 48RE or 68RFE for towing a heavy trailer.

Sorry missed the quote, just got to get used to the new TDR

 

[BILLUA]

I think it is also important to think about the speeds you will be towing at. For example, I tow generally at 75 mph, the speed limit here and most places out west. Obviously slower climbing the mountains if necessary.

For those that say "my truck with 3. 73's lugs" are you speed restricted to no more than 65mph due to st tires, speed limits, fuel consumption etc?

In other words, what speeds ya runnin?

 

[RustyJC]

75 MPH with the 4. 10s is 2015 RPM in 6th. I wouldn't tow a 16,000 lb 5th wheel that fast, but if I did, 2015 RPM is perfectly reasonable. My 2002 3500 with the NV5600 and 4. 10s was turning 2000 RPM at 60 MPH and around 2350 RPM at 70 MPH.

Rusty

 

[BILLUA]

Thanks Rusty, that just reinforces my desire to order 4. 10's in the new truck. The caveat is that the 6th gear ratio in the Aisin stays what the press release states. If it ends up different somehow, I'll reevaluate...

What's funny is my 05 runs 2050 RPM's @ 75mph with this 48RE and 3. 73's. so, for this combo, I am very satisfied.

 

[Cummins12V98]

I have the 3:42 gears. When I bought it I planned to change to 4:10 but I am really happy with what I have. Nearly 28,000# and on I-5 there are two small stretches I get down to 53mph but most of the steep passes I am at 55 or more. I am averaging 9. 5 mpg west coast hand calc I tow at 60-62 mph. In 6th I am around 1,400rpm and 5th around 1,800. I did some experimenting, looks like I am getting a bit better mileage in 5th.

To do it over I would get the 4:10 but it is amazing how well it performs.

Got a price from Dave Smith to swap both gear sets $1,800. Great price but he said I would then only have a 12mo 12,000 warranty and also he could not re calibrate the speedo. He is the service mgr so I figured he knows what he is talking about. Any opinions?

 

[RustyJC]

Got a price from Dave Smith to swap both gear sets $1,800. Great price but he said I would then only have a 12mo 12,000 warranty and also he could not re calibrate the speedo. He is the service mgr so I figured he knows what he is talking about. Any opinions?

Where does the truck get its speed signal? From the tone ring on the rear differential ring gear carrier? If that's the case, there's no speedometer recalibration involved.

Rusty

 

[HBarlow]

I have the 3:42 gears. When I bought it I planned to change to 4:10 but I am really happy with what I have. Nearly 28,000# and on I-5 there are two small stretches I get down to 53mph but most of the steep passes I am at 55 or more. I am averaging 9. 5 mpg west coast hand calc I tow at 60-62 mph. In 6th I am around 1,400rpm and 5th around 1,800. I did some experimenting, looks like I am getting a bit better mileage in 5th.

To do it over I would get the 4:10 but it is amazing how well it performs.

Got a price from Dave Smith to swap both gear sets $1,800. Great price but he said I would then only have a 12mo 12,000 warranty and also he could not re calibrate the speedo. He is the service mgr so I figured he knows what he is talking about. Any opinions?

With 3. 42 gears you've given up half of the load startability and hill towing power offered by the Cummins engine not to mention the exhaust braking of the VGR.

I recently drove a friend's new 2012 Ram 3500 w/800 tq engine and 3. 73 gear sets. Comparing it to my much heavier cab and chassis w/610 tq, 4. 10 gears it downshifts and strains more on the grades and offers less load startability.

The Cummins engine allows pulling incredibly heavy loads, even with bad gearing choices, but regardless of the defenses offered here differential gearing makes a huge difference when towing heavy trailers.