J OOPS

Just changed from 3.55 to 4.10 with limited slips front and rear. Love the gearing, getting ready for lift and 35" tires. Anyone want my 3.55 gears with carriers?

daddy mopar

OK, so 5 years later I am driving the truck daily again and am contemplating the same question. Transmission or gears? Ive been calling shops and the prices haven't changed 2-2400 for 4.10/11.

After reading what has been said by you guys up top and others, my new dilemma is to rebuild the transmission when it goes out or replace the gears and hope the transmission holds on.

turfguy

For 3500 you could have 4.10's swapped in & have $$ left over

Monstermaker

It costs a bit but I find the best of both worlds is 4.10 gears and a Gear Vendors overdrive.
On stock tires, 60 mph is 2000 rpm, if I hit the overdrive 60 mph is 1500 rpm.
I wouldn't want to be stuck with either of those. The 4.10s work when loaded heavy, and the effective 3.20 when the Gear Vendors is on works great when empty.
The cost of regearing gets you about halfway to putting in an OD.

dkenny

you don't mention that you tow..heavy if anything..
also think about adding a switch to lock up the torque converter when you want..not just in OD..the tranny temp will drop when the TC is locked.

also consider upgrading the injectors to some from the RV275 to 75hp injectors..you'll gain MPG and power..

then a tuner...you might gain more..I haven't added a tuner..but I did go from stock to 75HP injectors...BIG difference..MPG are up about 4

I'm only running 285's for tires and 3.55 gear, but tow a 4-5K trailer daily..its go all the power I need..any more and I couldn't keep tires on the rear..its too easy to burn rubber from a stop.

-dkenny

jefe4x4

I'm in the throes of changing gearing. Stock was 3.54:1 and that worked well with no load and stock 32" tires. As my tires and wheels got to 33" tall, 12" wide wheels, 16" wide tires, and heavier it was still doable but I was shifting the NV6500 more on hills. (Moron?) 375/65R16 on the left. 265/75R16 stock size tire on the right:


Now that I have 35" AT3's, a very heavy tire because of the lack of big voids, and heavy custom steel wheels for load carrying, the original gearing is out of the question. The Stockton wheels have 1/2" plate center hubs:

I used one of the cool gearing charts on the internet called grimmjeeper.com and found if I go to 4.10's I will be turning exactly the same 1600 rpm in 6th @ 55 mph as I was with stock tires and 3.54's. Remember too that the NV5600 has a 27% O.D. @ 0.73:1 in 6th. That's pretty tall.
60mph@1749 rpm
65mph@1895 rpm
70mph@2040 rpm
So, no need to adjust the speedo gear. I've talked to my gear man and he has a complete used factory set with carriers to make the swap. He said my Tru-Trac and Power-Lok are no problem.
I'll report back.
jefe

jda51

https://tiresize.com/gear-ratio-calculator/

jefe4x4

Thanks, jda51.
That was 4 years ago and I still have the Dodge TD. Still the best, most trouble free car/truck I've ever owned.

However, time marches on and because of the noise and my wife's unwillingness to drive the 6 speed manual any more with the camper on, we bought a 2020 Ford F-350 7.3L gasser to haul our also new 2020 Northstar camper.Transmission: TorqShift 10 speed 10R140 automatic

Gears 8, 9, and 10 are overdrive gears

First gear is one of the lowest of any automatic, made for trailer starting

First 4.615:1

Second 2.919:1

Third 2.132:1

Fourth 1.773:1

Fifth 1.519:1

Sixth 1.277:1

Seventh 1:01

Eighth 0.851:1

Ninth 0.687:1

10th 0.632:1

Reverse -4.695:1



transfer case ratios: 1:1 and 2.64:1

52.39:1 low range crawl ratio:

4.615 x 2.64 x 4.30axle ratio: 4.30:1

Your info did not go to waste. Here is the final drive (assuming 1:1, by the way) if i go up in tire size:Stock Tire Size 275/70R18 (33.2 inch diameter)
New Tire Size 285/75R18 (34.8 inch diameter)
Stock Gear Ratio 4.30: 1
New ratio needed 409:1
New Ratio Needed 4.52 : 1

jda51

here is a tire size calculator. maybe it will help.

https://tiresize.com/gear-ratio-calculator/

jda51

https://tiresize.com/gear-ratio-calculator/