dhe9

so i am thinking about ordering a 2011 later this week and wondering about the 3.42 ratio. my first CTD was a 2001 with a manual shift and 4.10 rear end. my current truck is a 3.73 with an 48re. my next and last truck with be the 2011 with a manual shift but not sure about the rear end.

can someone please explain advantages of the 3.73 and the 3.42 both with a clutch and manual shift. i plan on putting a camper on the back weighing about 3000 lbs dry weight.

don't need fast starts but would like the better fuel economy.

thanks,

david
socal

edc

My two cents: I have little experience with diesel trucks but have now put about 1500 miles on my 2010 with 3.42 ratio and 6 sp auto. I love the truck and the power and the ratio seems plenty low when judged by low speed response. My research (which included calls to Dodge engineers and discussions with experienced Cummins mechanics) indicated the 3.42 was the best choice for my use which will include some towing of a less than 6,000 lb trailer. With your camper weight I would think the 3.42 ratio should work well.
I am cruising at slightly over 70mph at 1600 rpm in 6th gear. I have monitored the fuel usage indicator on the inst panel and the engine seems to like running at what I would have considered too low rpms (e.g. 1400 to 1700). Clearly a different beast than a gas engine. Ed

djcheez

you should be fine with those gears unless towing much heavier and or going with larger tires.

NCPADiesel

I have an '09 6 spd manual with 3.42s. As long as you're not towing heavy it works great. Pulling hills it will run out of power with a load on...but I should be shifting down anyway.

67guzzler

Ya -- If you're getting the G56, you want the 3.42. You'll hate the 3.73 with the G56 on the highway....

I saw this chart below in another thread a while back:

G56 Manual w/0.74 final drive ratio in 6th gear, 265/70-17 tires, 654 revs per mile @ 70 mph:
3.42 axle -- 1931 rpm at 70 mph
3.73 axle -- 2106 rpm at 70 mph
4.11 axle -- 2321 rpm at 70 mph (combination NOT available -- just for comparison)

6-Speed Automatic w/0.63 final drive ratio in 6th gear, 265/70-17 tires, 654 revs per mile @ 70 mph:
3.42 axle -- 1644 rpm at 70 mph
3.73 axle -- 1793 rpm at 70 mph
4.11 axle -- 1976 rpm at 70 mph

The last column is the RPM's at 70 mph. Note that the 6 speed automatic with the 4.11 isn't much worse on the highway than the G56 manual with the most economical option, 3.42 -- Both around 1950 rpm's.

dhe9

thanks for the information, looks like the 3.42 is the way to go. can't order the 2011 until middle of june. dealer tells me that they don't have any of the pricing info yet. i plan on getting it for invoice then the $1500 incentive and the military retired incentive being $500.

when i was talking with the dealer they were more than ready to sell for invoice.

thanks again for the info on the 3.42 and if i run out of steam i can drop it down to 5th.

one last question, i have a hip problem and wonder if the clutch on the G56 is the same level as the brake? i can move my left leg that high but if the clutch peddle is any higher i may have a problem. so are both brake and clutch about the same level?

thanks,
david
socal

67guzzler

On my 2005, the pedals are the same height. Not sure on these 2010's.

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Blake Clark

Thanks for this info... good stuff....

Im planning ahead for my 4th Gen and want a G56 next time. Want to get the gearing just right. Right now, Im wishing I had went with the 4.10's on my 08 (68RE, 3.73) running the 35 inch Toyos.

What would be your opinion on the G56 3.73 running 34 to 35 inch tires?

67guzzler

I had the G56 with the 3.73. It was an older G56 with a .79 final OD ratio. In the 2005 model year, they didn't have a 3.42 gear set yet as AAM hadn't come out with it yet. I was turning 2200 rpm at 70 mph with stock tires. I hated it. It was a dark time for engineering at Chrysler and AAM. The reason was they had a mid year switch from the NV5600 and the G56 and didn't realize the impact with the 3.73. When I ordered, they were still shipping the NV5600's but they shipped me a G56. I got over it but I wasn't happy.

NOW -- The newer G56 (last couple years) is a at least a little better at .074 AND you have the option to go with the 3.42.

Obviously I would have killed to have a 3.42 even when I was running 315-70-17's.



Remember, you're shifting anyway -- what's the crime in downshifting to 5th? The real issue is on the other end -- getting your rig moving. Again, 2nd gear is so low (1st is the stump puller) than you won't have any problem. I mean, on my G56, I was out of 2nd so fast that I started in 3nd some of the time.

You can't compare your experience with the 6 speed auto to this. That transmission has such a steep overdrive in the final gear (.63) that a 3.73 or 4.10 is very nice. In my opinion, with the G56, even with the newer .74 OD and bigger tires, you're still ahead of the game with the 3.42 and you reserve your highway RPM's. Remember, you can down shift but there's nothing you can do to lower your rpm's if you go with a 4.10. Just my $.02.

Blake Clark

Thank You Pat

Thats the kind of insight I was looking for.

djcheez

Sure you can, its called bigger tires

RowJ

Good discussion on 3.42 Rear End Gears HERE

I agree with 'Patriotblu', 3.42 makes perfect sence on a 6 speed.... unless towing heavy (20,000 lb +) all the time.
Or- 3.73, w/ 35" tires, will net you a 3.54 rear net! To my mind,that's just about a perfect combo.
That's my plan.... if I ever pull the trigger on the 2010 I want..... but it will be a 6 speed automatic!

RJ

Silver Ram

6-Speed Automatic w/0.63 final drive ratio in 6th gear, 265/70-17 tires, 654 revs per mile @ 70 mph:
3.42 axle -- 1644 rpm at 70 mph

This blows my mind!
What kind of fuel mileage does that bring?

RowJ

Maybe a bit better.... but I doubt it. I think 1600's for cruise is a bit low for the sweet spot.
I know it is low for cruising at 425 hp in the plains states, but may be good for stock... especially in more congested areas.??

My 3.54's with 35" tires nets out at 3.24 rear end and 1800 rpm at 80 mph.
Never saw any gain in mileage over 265's..... but that could be due to 80 mph.

RJ

signature600

My 2010 with 3.42's, stock 265/70R17 tires, and Auto is getting about 16-17mpg combined city/highway mileage.

2010 3500 CC LB 4x4...I'm happy with the mileage, but better yet would be nice!

Chris

On my old 98 I ran 3.54's, Auto and 36.3" tall, 145lb each 285/70R19.5's, and the 6.7L drive WAY nicer than that ever did, even with 150hp less!