Changing differential gears

I would suggest a Durango forum for specific information for your SUV would be more accurate...unless someone has a Durango with a Hemi here?

Depending on which way you go you could gain a bit or loose a bit in fuel economy. It also depends on of you have a 4X2 or a 4X4 what the cost will be. Payback? Not likely in this lifetime. Could you have a better towing experience? Possibly. Again it depends.

I know next to nothing about Durango power trains. My old '97 F150 came with 3.55 gears, a very weak 4.6L V8, and a 4 speed auto. I upgraded the gears to 4.10s with great success. It was like a new truck.

It looks like our next RAM 3500 SRW will have to have 3.42 diff (unless they change for 2020 with gen 5) so it is entirely possible I will have them changed out for 3.73 or even 4.10 within a couple of years.

Why not just get a Gear Vendors auxillary box and keep your ratio and pick up a few extra ones? They are bolt on.

SidecarFlip wrote:
Why not just get a Gear Vendors auxillary box and keep your ratio and pick up a few extra ones? They are bolt on.

VERY EXPENSIVE !

I am assuming the OP wants to swap in a higher gear ratio for better towing, especially on hills.

There is no "payback" on this except the peace of mind when you are going up hill and able to keep up with traffic and not having to worry about hitting you in the rear end because you are only going 25 MPH !

Don't forget, you will probably have to go to a dealer to have them change the ration inside the PCM so that the speedometer reads correctly and the transmission shifts correctly.

Expect about 1500 per axle unless you do it yourself, which you're not if you're asking this question. Yes it helps. IMO, not worth it unless a specific situation. Easier to upgrade to a similar value vehicle with more power or deeper gears IMO.

If it's a 2wd and you know what you're looking for, a junkyard 3rd member swap is cheaper and easier, again if you're doing it yourself.

I would have to guess you have the 3.55`s. I`m assuming you want to go to 3.90 or 4.10. 3.90 was a factory option. If you have 4WD you have to do front and rear. It could get expensive! However it will make the Durango perform much better. If you want to keep the Durango it is a worth while mod.
I had a Dodge conv van with the 5.9L and 3.55 gears. I went to 3.90`s and it was a huge improvement! solo hwy mileage went down, but around town and towing mileage went up.

Its not cheap if you have to pay to do it, but from a performance stand point well worth it!

Yes very happy going on 12 years after swapping 3.55 to 4.10 ratio.
Yes improved drivability both towing and unloaded.
Very worth it if you are keeping the vehicle.
No real downside except that I had to buy a programmer to fix the speedo.

Also swapped in Trutrac differentials that really improved off pavement traction. :)

ScottG wrote:
It looks like our next RAM 3500 SRW will have to have 3.42 diff (unless they change for 2020 with gen 5) so it is entirely possible I will have them changed out for 3.73 or even 4.10 within a couple of years.

With the AISIN the 3.42's are good to over 29k combined SAE rated.

Change gears and you go from 100k coverage to 12k or one year.