Ok i have 99 dodge ram 1500 with a 8" suspension lift and i want to put some 38's under it the tires are 38x15.50r20 toyo mt open country

im looking for the right set of gears for it for front and rear i have been looking around at all the messaging boards and everything and some people say 4.56 , 4.88 and 5.13 are good gears to run i mainly use it as a daily driver but take it off road some times i want something that will give me about the same gas millage that im getting now which is 10mpg and a little power. i just want to know the absolute best thing for what im looking for its got the dana 44 9.25 rear end

thanks

 

4.56 will keep the speedo close to accurate (will actually be going slower than indicated) with 4.28 gears yielding an equivalent gear ratio, but you will be at a power loss due to the higher moment of inertia of the 38" tires, so I would say that if you want to keep your feeling of power to go bigger than 4.56.

 

4:88 is what I would use, but that's me. These versions of the Dana 44 with unit bearings don't take well to any tire over 35".

 

I don't think the gears have anything to do with speedo readings in a '99.. that is handled by the sensor in the axle.. I think you can cram a 4.88 in a Chrysler 9.25, but only a 4.56 in a dana 44 (nobody makes 4.88 for the front- 4.56 is the deepest)..

with those 38's, I would guess 4.56 at a minimum in gear ratio selection, and also economics- because if you go lower, you'll be doing a LOT more work than just ring/pinion.. just my .02....

 

Nope, on 98 and newer, the 'speed sensor' is on the rear diff, and simply counts differential revolutions to calculate speed. Keep in mind though, that is based on the STOCK tire size. Larger tires are going to cause your speedometer to UNDERESTIMATE your speed. (you will actually be going faster than what your speedo is telling you. changing gears will NOT change this. Need to update the computer, to reflect the new situation....... Some tuners can do that, others cannot. Not sure if the dealer will do it for you.... even though they should have the capability to do so..... should......)

38's on the Dana 44 though is going to be pretty rough on it. Better invest in a company that makes them, and associated parts, as you will go thru them fairly regularly..... You would be better off upgrading to dana 60's, then, you could get a better gear ratio, and MUCH stouter axles.

 

Some Dana 44 info and link to parts. 8" lift+38"tires+4:88 gears= 8mpg, I have ran a few trucks(chev,ford,dodge) with just that combo and that's about it for gas mileage.

38x15.50r20 toyo mt open country time to upgrade to Dana 60"s


Dana 44
Ring gear diameter: 8.5”
Carrier Breaks: 3.73-lower, 3.92-higher
Pinion shaft diameter/Splines: 1.125/10
1.376/26
Inner axle shaft diameter/splines: 1.25/ 19 (to-66), 1.31/30 (66-on)
Outer axle shaft diameter/splines: 1.21/19
Cover bolts: 10
Available ratios:2.72, 3.07, 3.31, 3.54, 3.73, 3.91, 4.09, 4.27, 4.56, 4.88, 5.13, 5.38,5.89




http://www.4wheelerssupply.com/catal...2a765160aa53db

 

dang... I stand corrected.. If I had known this a couple weeks ago, I would have went with 4.88's!!

 

i would give drews left nut to go back in time and put 4.88's in my truck instead of 4.56s... When debating on a ratio, I just remember that I have never found someone that said they went to high ratio on gears...

 

I'd agree on 4.88s as well...

 

I'd say flatly to not go that big on stock axles, regardless of available ratios.

As mentioned earlier, Dana 60's required and my personal opinion is 5.13's for the tranny's sake.