03 rear end ratios

[Sageair]

I think Dodge is making a mistake by replacing the 3:54 rear end ratio with the 3:73. Not that the 3:73 is bad but I often find myself wishing for taller gears because of all the power the H. O has and the wide open spaces of Nevada . I think they should have offered the 3:73 as another choice but not a replacement for the 3:54's

 

[forr]

I'm still not sure how the 3:73 ratio will turn out. I think the 3:54's are marginal for heavy towing, but have no complaints about highway travel. You made a good point. With the manual transmission, the 3:54's sure a nice when you're on a long stretch of interstate.



Right now I have more concern over the change in differential/rear manufacturers than I have over the 3:73's.

 

[HiPerf360]

I would like to see a 3. 08 gear ratio, this way you could cruise in overdrive and pull in 1:1. I pull 25k+ loads regularly and that would be a perfect setup.

 

[Cummins Corvette]

I too would like a 3. 08 option for the same reason.

 

[kchristopher]

Originally posted by HiPerf360

I would like to see a 3. 08 gear ratio, this way you could cruise in overdrive and pull in 1:1. I pull 25k+ loads regularly and that would be a perfect setup.

That's the truth. Then your direct (which I think would cause the least heat build up in the transmission) would be the same as 4. 10 in OD. And 1st gear would be more useful. If they only made 3. 08 gears for front end (not much chance given the gasser market).

 

[SlyBones]

Originally posted by HiPerf360

I would like to see a 3. 08 gear ratio, this way you could cruise in overdrive and pull in 1:1. I pull 25k+ loads regularly and that would be a perfect setup.

Enlighten me here. Seems that if you have 3. 54 and want 3. 08 all you need is somewhere in the neighborhood of 36" tires on that baby.



I think 3. 73 will be nice for the average guy placing 285's or so on the truck. You will end up with about 3. 54 when its all done. Right?

 

[MCummings]

That would be 285's for 17" rims



Gonna be EXPENSIVE to be changing tires on the new HD's



Sure would like a 3. 08 rear-end also,, Dana does make a 3. 23 for the Dana 80.



I don't think I could fit 36" tires under my 2wd.

and a $2K overdrive unit is just :--)



Merrick Cummings Jr

 

[Barry]

You guys keep going and you'll have that motor down to 600 rpm at 80 mph.

 

[MCummings]

Barry,,

You say it like that's a bad thing

Although 1,500 at 70 sounds good,, or maybe 2,500RPM @ 130MPH. :--)



Merrick Cummings Jr

 

[kchristopher]

Originally posted by SlyBones





Enlighten me here. Seems that if you have 3. 54 and want 3. 08 all you need is somewhere in the neighborhood of 36" tires on that baby.

But then it wouldn't fit in the parking garage at work. I've done it plenty of times and it still makes me pucker going thru it.

 

[Beast2B]

36 tires?

I have 37" tires on my truck with the 3. 54 ratio, and I don't like it. First gear is still too low for everyday starts, but second is too high. Sixth gear is great over 45 mph, but fifth is too low for 40-45 mph. Maybe I got used to the 265 tires with the 3. 54's, but I am heading for a gear change to 4. 10, which will put me very close to the original final ratio. JUST MY $0. 02, anybody got change for a penny?

 

[MCummings]

I'm begining to think that RPM is becoming a factor in this.



What RPM do you say is to low, and what RPM do you think is to high??

What is your opinion?



My Opinion is that in 5th gear below 1,500 RPM is too low

and in any other gear 1,200RPM is too low and 2,300RPM is to high. (Cruising, unloaded)



When running hard,, I go ahead and ramp her up to shift at 3,300RPM I don't like to be at WOT anything below 1,500RPM.

I have a 5-speed

and 90% of the time I start in 1st gear



Merrick Cummings Jr.

 

[klenger]

It's becomming apparant to me that the problem with finding the perfect rear end ratio is that the Cummins has a narrow RPM range compared to a gasser. I agree that the comfortable RPM range is 1500 - 2300. It seems that the only solution is lots of gears to pick from. With my 4. 10's, I just don't drive fast on the freeway. Tows like a S0B though.

 

[danandamy]

I personally think it will be a good option. I agree that I don't see why it has to be an "Either or" type deal, I mean it wouldn't kill them to offer more than two choices of rearend My observation has been however, that the 3:54's are a bit tall many times for towing but the 4:10's tend to have you running such a high rpm when you're just running solo down the highway. I think the 3:73's will work out great.



optimisticdan

 

[juicedcummins]

308's please or even better 276's. Now that would make an excellent cross country cruiser!:--)

 

[Beast2B]

add horsepower!!

I may have to change my opinion now that I have the Comp on!

I have the equivalent of 3. 05 gears with my actual 3. 54 gears and 37" tires, and with the Comp on 1x1 or 2x2 the lack of go power seems to have diminished... I don't even have the fuel pump wire attached yet!

No freeway trips yet, but sixth gear over 50mph should be a mega-cruising gear...

 

[Phil May]

Curious

I have a 91 with a NV4500 and 4:10 235/85r-16 tires top speed is only 82-85. What would the top speed be for an 03 with the 4:10 and the 17" rubber be and the top Speed for 3:73 with 17" rubber. How much difference in circumference Between 235/85R-16 and the new 17".

 

[klenger]

Tire size calculator

 

[amsoilman]

It seems to me when the first Dodge with the Cummins Engine, the rear end ratio was 3. 08. I think this was in 89'. I may be wrong, but it seems thats what it was.



Wayne

amsoilman

 

[srawleigh]

3.08 ratio

Amsoilman,



You are correct regarding the 3. 08 ratio in the 1ST generation Cummins equipped trucks. The difference is that the original A/T equipped trucks used a beefed up version of the 3 speed 727 transmission (no overdrive). With lower gears and no overdrive, the truck would only be able to go 65-70 mph.