I realize the tv cab,e won't change gear ratio, I was just trying to figure something out. I as guessing tho that he had to have diff gears than stock.

 

Previous owner may have regeared it....... and not done both ends. That would really foul things up in 4x4.

 

Ok, to the OP, go 4:56s. Made a noticeable difference, got 10.5 mpg with no overdrive running 3k rpms at 55-60. Wildman, nice explanation but wrong axles. If this is the truck in the guys sig, its a 3/4 ton meshed with a 1 ton. Somebody probably put the wrong gear ratio axles in it. But he should not have a D44 and Chrysler 8 1/4. Back to Blue Mopar, smaller tires = higher rpms. You have 31s and he has 35s on who knows what gear ratio. But if he has 3.55s same as you, he will have much lower rpms. Also why Green Ram is right between you two on rpms with 33s. Whew, rant done.

 

Made sense in my mind, thanks for backing that up and the input on gear ratio.

 

Okay lets figure out what gear ratio you have in both axles first.

Jack up the drivers side of the rear axle. Take a marker or chalk and draw a line pointing to the ground. Then take a piece of string that is 36" long and tape it to your driveshaft @ the 6 o'clock position about 10" in front of the rear u-joint. You stay under the truck and watch the string and have someone turn the tire two complete revolution. As the driveline turns the string is going to wrap around the driveline. When the tire has turned around once count how many times the string has wrapped around the driveline. If you can take a picture for us. You can do the same thing with the front axle but you need to have the transfer case in high or low range so it engages the axle disconnect. Then jack up the drivers side of the front axle and do the same thing you did with the rear axle.


This video shows how to check a open diff and one with a limited slip.

 

Hello all, I am here to revive yet another thread. I am going to re-gear in the next 2 months or so and also put a trutrac in the front axle and I have seen thick cut and thin cut gears. I am not really sure on what gears I should get since there are thick cut and thin cut gears for the Dana 44. I am pretty set on 4.56s since i'll eventually be running 35s, I am aware that there can be problems with 35s and a locker with the 44 but this is only a temporary setup till I can buy some 3/4 ton axles.

 

Thick or thin depends on which carrier you get. If you get one for 4.10 and down, then for 4.56 gears, you will need the thick ones. If you get the 4.10 and up carrier, then the thin, or, standard gears will work.

 

I currently have 3.92s from factory and I plan to stay with the same carrier for the locker, so since I have and will be getting on the high side of the carrier break, I would be getting standard cut and not thick cut, correct?

Here's the link for the place I am getting my gears and locker from if anyone is curious.
https://www.drivetrainshop.com/Produ...3A592&CartID=1

 

Break point is 3.92? Ok..... Then yes, regular gears, not the thick cut fellers.

 

I couldn't tell you what kind of 4.10's I have in my axles other than Yukon brand. I didn't order parts, my shop did. Update on the gears, I love the 35's with 4.10's!