2nd Gen Non-Engine/Transmission 4.10 Gears on '96 dually puzzlement

[Vaughn MacKenzie]

You guys with 4. 10 gears on your dually 5-speed, what RPM are you seeing at 70mph??



A friend just picked up a '96 dually 4x4 with 4. 10 gears. We took it for a spin and it's geared lower than I would have dreamed for having 4. 10s. In 5th gear going down the freeway, at an indicated 70mph, he's spinning over at 2700! What's up with that?? I thought it would be more like 2300-2400. I know Rob Hanson has 4. 10s and 215s on his dually and he runs around 2400rpm at 70. I am quite puzzled. The factory tire size I believe is 215/85/16 and so that's what the speedo should be based on. I would have never dreamed 4. 10s would be that deep on a dually but maybe I was wrong. I'm certain the tach is correct because it sounds like 2700rpm. . . it's really wound up.



The truck maxes out at indicated 77mph (3000rpm). He went with 4. 10s since he's planning to load it heavy with a slide-in and towing a boat but I'm thinking with the dually tires (he has 235s on it now) the 3. 54s would have been perfect. Running close to 3000 RPM all day long is just going to kill his mileage and make the ears weary.



Vaughn

 

[bmoeller]

5spd- . 75 ratio or so.



Auto- . 69 ratio.



http://www.dodgeram.org/tech/specs/Ramspecs.htm



http://www.dodgeram.org/tech/specs/axle/rpm_vs_mph.htm



70mph at 2700RPMs sounds about right. I hit 75mph at 2700RPMs with the auto and 4. 10s.

 

[Chipstien]

The 5 speed with 4. 10 gears and 215 85 16 will be as follows... ... .



2000 - 59 mph

2200 - 65 mph

2400 - 71 mph

2600 - 76 mph

2800 - 82 mph

3000 - 88 mph

 

[Turbo Tim 1]

I turn 2200-2300 at 73 mph with 255/85 which are 33 inches tall the 215's are like 29 inches tall so that's probably pretty close. The tow truck at a dealer I use to go to had 4. 10's and the guy told me that on the govenor it do 75 mph and it was a 12 valve.

 

[jtwcummins]

That's why fuel economy goes in the toilet driving 70-75, lots of revs. I can get to almost 90 before guv says no more. Running 265-75-16 tires so real speed is different than speedo. 4. 10 is nice for towing, but you pay for them every day.



&yrs average MPG

City 13. 5

Hiway unloaded 18. 9

Towing 13. 1

 

[ErniePink]

I agree with Chipstien's figures and my experience with my '96 3500 5 speed dually. Mileage never averaged over 18. 5 but was crowding 19 when I traded at 85K for my 2002. I always ran with the 215's. Hope this is of some help.

 

[jtwcummins]

Thats 7 yrs average!