I need some help.
My truck is not stock as you can tell in the sig.
I need to know what one of these trucks will run with stock or close to stock tires, auto trans heading down the freeway at about 70 mph.

With 38's and 4.10's Im right around 17-1800.
I'm thinking my converter is way to tight stalling @ 1200 but I need some "stock" rpm info for comparison.

Thanks

Dan

 

hope this helps...

http://dodgeram.org/tech/specs/axle/47auto.htm

it will atleast tell you the stock numbers you are looking for.

 

thats perfect thanks.

 

Truck in my sig.

75mph is 2200rpm so I'd guess 21xx @ 70.

All stock with the 47re trans with 265/75r 16's

Bill.

Edit, 3:55 gears

 

With the exception of an Airraid dropin filter, on the freeway @ 70, the tach shows just shy of 2000
This is with 3.73 gears and 4 spd auto.

 

I've got 35's with a 3.54 rear end and an auto tranny and with my speedo corrected I'm turning 1800-1900 rpm's at 70mph.

 

For comparison, I'm running 235-85-16s and a 4.10 gear.
Indicated 60mph is ~2000 rpm.

(truck came stock with 215-85-16s)

 

I run 265/75R16 tires with 3:54 gears and at 2000 rpm I am running 70 mph. When my speedometer says 61 mph my GPS says 60 mph.

 

Ditto.....Same setup for me and GPS shows just under 59mph.

 

Guess that means I'm running 4:10 gears...forgot how to check and haven't located it with a search yet...60 @ 2100 RPM...guess that shoots any hope of good highway mileage 'cause I ain't got all day to get there (like keeping the "R's" under 2 grand)...anyone wanna offer suggestions to a newbie on how I could improve this situation short of replacing the gears...I'd like to do a few upgrades such as 4" exhaust, better airflow at the intake, a chip/tuner of some sort and do I understand correctly that larger diameter tires will help???

I appreciate any advice offered!
John

 

285/75/16 3:54 very close to MnTom rpm

 

Before swapping from 3.55's-4.10s this is r's I was looking at, with the 265's on in sixth gear I was running 70 at 2000rpms. With 315's, I was running 78 at 2000rpms. 4.10's, 255/85/16's I was running 2000 rpms at 65. With the 315's on at 70 I am turning 2100rpms. Fuel economy has gone down more that I thought it would for highway cruising. usually run 73 or so. Looks like I need to get a US gear overdrive to take me back to the happy spot of 80 at 2000rpms. Any questions on gears and rpms, I have had many different sizes of tires on my truck and can tell you what rpms.