4:10 or 3:73 ?

I owned a 2001.5 with 4:10 gears for 14 years. I have to say after getting the new RAM, I would never want to have to be limited on ease of freeway cruising again.

RCMAN46 wrote:

Never understood why we have to tow in 6th gear or the top gear.

That is the whole purpose of a transmission. I agree the 3.42 is the ideal rear gear for the Cummins with the Aisin.

Unloaded as said you can cruise at a comfortable and fuel saving rpm even at 80-90 mph which I often see out here in the west with speed limits at 80 mph.

Never said I have to tow in high gear. What I was trying to say is not everyone needs the gearing for high speed unloaded use. Gear for the speed you drive. The amount of non towing miles that I drive my truck is very low, and most of that is below 60. And I get that seat of the pants the 3:42 in 5th is equal to the 4:10 in 6th. Either would be a big jump from the 305 hp 5 speed truck I now have. I would rather have the extra gearing down low, even though I know it's not really needed.

Me Again wrote:

jaycocamprs wrote:
The DW and I have begun talking about replacing the current 05 Duramax with a new truck. Question is another GM or the Ram, it won’t be a Ford. I get what yall are saying, at the 12k scaled weight that we are running I could get by with a SRW 6.4 Hemi. But we have a DRW diesel truck, and we don’t want less than we now have. I know that the Cummins with a 3:42 will pull this or even a larger trailer just fine. I also don’t need a DRW truck that cruises 80 MPH empty. I just don’t drive that fast. In this part of the country that will get you face time with a LEO, and that is something I try to avoid. Fact is I want a TV pull my trailer up to 65 MPH in comfort on cruise control. I rarely drive my current truck long distance or on the interstate not towing. I have other vehicles for that. So a truck that won’t shift into top gear below that speed towing does not make sense to me. So if a Ram with a Cummins and 4:10 gear tows it like it’s not there, it’s ok. I won’t come back and complain about having too much truck. And if we ever buy a larger trailer, I won't have to worry if I have enough truck.

You are still not understanding the beauty of the 3:42's and Aisin tranny. You do not have to be in 6th to tow 65 RPM with the RAM set up that way. 5th will be about the same RPMs and 4:10's in 6th.

Unhook the trailer and you cruise at comfortable low RPMs in 6th at 60, 65, 70 etc. It will shift to 6th at lower RPMs when not in tow haul.

Chris

Never understood why we have to tow in 6th gear or the top gear.

That is the whole purpose of a transmission. I agree the 3.42 is the ideal rear gear for the Cummins with the Aisin.

Unloaded as said you can cruise at a comfortable and fuel saving rpm even at 80-90 mph which I often see out here in the west with speed limits at 80 mph.

jaycocamprs wrote:
The DW and I have begun talking about replacing the current 05 Duramax with a new truck. Question is another GM or the Ram, it won’t be a Ford. I get what yall are saying, at the 12k scaled weight that we are running I could get by with a SRW 6.4 Hemi. But we have a DRW diesel truck, and we don’t want less than we now have. I know that the Cummins with a 3:42 will pull this or even a larger trailer just fine. I also don’t need a DRW truck that cruises 80 MPH empty. I just don’t drive that fast. In this part of the country that will get you face time with a LEO, and that is something I try to avoid. Fact is I want a TV pull my trailer up to 65 MPH in comfort on cruise control. I rarely drive my current truck long distance or on the interstate not towing. I have other vehicles for that. So a truck that won’t shift into top gear below that speed towing does not make sense to me. So if a Ram with a Cummins and 4:10 gear tows it like it’s not there, it’s ok. I won’t come back and complain about having too much truck. And if we ever buy a larger trailer, I won't have to worry if I have enough truck.

You are still not understanding the beauty of the 3:42's and Aisin tranny. You do not have to be in 6th to tow 65 RPM with the RAM set up that way. 5th will be about the same RPMs and 4:10's in 6th.

Unhook the trailer and you cruise at comfortable low RPMs in 6th at 60, 65, 70 etc. It will shift to 6th at lower RPMs when not in tow haul.

Chris

The DW and I have begun talking about replacing the current 05 Duramax with a new truck. Question is another GM or the Ram, it won’t be a Ford. I get what yall are saying, at the 12k scaled weight that we are running I could get by with a SRW 6.4 Hemi. But we have a DRW diesel truck, and we don’t want less than we now have. I know that the Cummins with a 3:42 will pull this or even a larger trailer just fine. I also don’t need a DRW truck that cruises 80 MPH empty. I just don’t drive that fast. In this part of the country that will get you face time with a LEO, and that is something I try to avoid. Fact is I want a TV pull my trailer up to 65 MPH in comfort on cruise control. I rarely drive my current truck long distance or on the interstate not towing. I have other vehicles for that. So a truck that won’t shift into top gear below that speed towing does not make sense to me. So if a Ram with a Cummins and 4:10 gear tows it like it’s not there, it’s ok. I won’t come back and complain about having too much truck. And if we ever buy a larger trailer, I won't have to worry if I have enough truck.

The charts and data are not in perspective as values are different. The Cummins has a redline of 3K. That is a short and flat power curve, really. The 8.1 doesn't compare to the diesels.

The Duramax is a sweet motor and I love the GM trucks. But I will stick to my Cummins. I do not care if my 8.3 or 6.7 Cummins is popular with the "in" crowd, I just like that they keep plugging along, cool and quiet.

W

RCMAN46 wrote:


If anything the 8.1has a flatter torque curve than the Cummins.

At less a half of the Cummins.

Chris

The Cummins torque curve looks more like the 8.1 than the Duramax.

If anything the 8.1has a flatter torque curve than the Cummins.

It is interesting that the Duramax gets to max torque at a lower rpm than the Cummins.

I would stay with the 3.42s. The new transmissions compensate for the lower rear end. IF I DID......go ahead and take the time to swap them out.....I would go straight to 4.10s.

William

RCMAN46 wrote:

cdlaine wrote:
Not nearly as scientific about it as many of these posts...
Year 14 on my 8.1L with 4.10 rear end and Allison. Pull an
Artic Fox 295T. Still very pleased with performance, towing,
dependability. Have accepted MPG as "is what it is" . Cannot
think of an instance where I regretted getting the 4.10.
Reassuring to know I have it if needed.

Charles

If we use the 8.1 gas as the standard with a 4.1 gear as ideal then the Ram 6.7 diesel would work best with a 2.73 gear.

8.1 max hp is at 4200 rpm the 6.7 is at 2800 rpm.

4200/2800=1.5 thus 4.1/1.5=2.73

Pretty fuzzy math. Inline diesels make towing power a little differently than gas V-8s and even diesel V-8s because of their longer strokes.

I am towing at 24,500 combined weight and seldom exceed 2300 RPM, and that is towing in the Western States. 95 or higher percent of over the road trucks are I-6's for that reason, with some of them having three times the torque number vs the hp number. Chris