6th gear most of the time.

[Mr.Wilson]

Do you really need lower gears? Do you find a want of more torque or better low speed control? With a Max Tow, you don't have the 4:1 transfer case so lower gears would be big help when in 4-Low.
If your only question is for highway speeds, then I would not worry about it.

The chart be low is straight math, no slippage or efficiencies calculated.

It gives you effective gear ratio in a given gear versus differential gears.

A/T

M/T

3.73​

4.1​

4.56​

4.88​

5.13​

1st

4.71​

5.13​

17.57​

19.13​

19.31​

21.03​

21.48​

23.39​

22.98​

25.03​

24.16​

26.32​

2nd

3.13​

2.63​

11.67​

9.81​

12.83​

10.78​

14.27​

11.99​

15.27​

12.83​

16.06​

13.49​

3rd

2.1​

1.53​

7.8​

5.71​

6.2​

6.27​

6.66​

6.98​

10.25​

7.47​

10.77​

7.85​

4th

1.67​

1​

6.23​

3.73​

5.77​

4.1​

7.61​

4.56​

8.15​

4.88​

8.57​

5.13​

5th

1.28​

0.81​

4.77​

3.02​

5.25​

3.32​

5.84​

3.69​

6.25​

3.95​

6.57​

4.16​

6th

1​

0.72​

3.73​

2.68​

4.1​

2.95​

4.56​

3.28​

4.88​

3.51​

5.13​

3.69​

7th

0.84​

3.13​

3.44​

3.83​

4.1​

4.31​

8th

0.67​

2.5​

2.75​

3.05​

3.26​

3.44​

Yes, changing to 4.88's will give you an effective ratio in 7/8th gear (4.1/3.26)similar to what you have now in 6th gear (3.73) Either way, the engine is finding it's correct rpm at any given speed, it just doesn't currently need 7th or 8th to obtain it.

You could further extrapolate and multiply your tire rotations per mile by the effective gear ratio above to find your rpm at 60 mph.
with true 35's (given 593 rotations/mile)
6th gear 2212 rpm
7th gear 1856 rpm
8th gear 1483 rpm

Not knowing what the torque converter stall speed is or where lock-up is, I would guess that 8th gear at 60 would not lock the converter and cause slippage, heat general badness etc..

no I’m not looking for anything but to hit 7 & 8 a little more. I ordered the truck with 4.10’s knowing I was gonna put 35” tires on it immediately. Thus the reason I got it with the max tow package. Now after all that I guess it’s just not performing as I well as I expected (hoped) it would.

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[WILDHOBO]

Yes, I'll agree with you when it comes to weight of tires. It seems like everything is heavy Load Range E anymore. It's hard to find Load Range C or D tires. It's more than just breakage, it's the wear and tear that larger tires put on a Dana 44.

The Mickey Thomsons are D in 37”.

 

[Akgladiator]

I've got a 2022 JTRD with 37's (BFG 37x12.50x17 KM3's, and 2 inch Mopar lift, dealer installed, plus 4.88, dealer installed) , runs in 8th gear on the freeway, all the time, even uphill, at 75 mph+. Runs right at 2,000 rpm at 68 mph. Love it. Beautiful! Wouldn't bother with 4.56. This suits me just fine, until my Tesla Cybertruck arrives, then, it will instantly be, "Buh, bye, JT, hello CT3!"

The world's going all electric, and faster than anyone ever thought!

WooHoo! Love Elon Musk, baby!

Wait until your cyber truck catches fire on it's on, then will be buh bye to it too!

 

[Fox940]

The Mickey Thomsons are D in 37”.

Yeah, they're out there but few and far between compared to E rated tires. I put C on my JT. When I got my Power Wagon it had D's and I replaced them with E rated Coopers. When the Coopers wear out I'm going back to D rated. Looks like my options are Toyo or Yokahama. THe Hankook MT's are even discontinued now. I lost a MPG by switching tires.

 

[WILDHOBO]

Yeah, they're out there but few and far between compared to E rated tires. I put C on my JT. When I got my Power Wagon it had D's and I replaced them with E rated Coopers. When the Coopers wear out I'm going back to D rated. Looks like my options are Toyo or Yokahama. THe Hankook MT's are even discontinued now. I lost a MPG by switching tires.

MT Baja Boss A/T has a bunch of sizes. I’m very happy with them.

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