Cummins12V98 wrote:
otrfun wrote:
Cummins12V98 wrote:
Significantly?
3.42’s in 5th VS 4.10’s in 6th both @ 1,750 @ 60???
Although the OVERALL gearing in your example (5th gear w/3.42 vs. 6th gear w/4.10 = 1,750 @ 60mph) is more or less equal, the driveline/torsional stress, which is determined by the rear end ratio, is NOT equal.
Again, there is a reason why, a Ram Cummins DRW, with a 4.10 or 3.73 rear end will have a higher tow capacity than the same truck with a 3.42 rear end. Simply downshifting a Ram Cummins DRW with a 3.42 rearend will NOT increase the tow capacity, or decrease driveline/torsional stress. Only changing the rear end ratio can accomplish this.
Totally understand all that but to say "Significantly" IMHO is overstating the situation.
Here is my rear diff at 65k on my 11 RAM DRW. 2/3 of the miles were towing combined 29-30k. If something were to suffer I guess it wasn't the diff.
Oh and how about the trans? This is at 65k with 55k on the fluid. One would think there would be a lot more stuff in the pan. All I did was pop the drain plug.
This isn't flat land towing, 90% or more is West Coast Mountains.
If all I did was tow 34-36k I would get the 4.10's for sure. But towing 1/2 of the time or less the 3.42's are GOLDEN.
Maybe they look so good because I was running AMZ/OIL. :B
Take a look at the 2014-2018 Ram tow capacity ratings for the 3.42, 3.73, or 4.10 rear ends.
There can be as much as a 8,000 - 9,000 lb. difference between a 3.42 and 4.10 rear end (same make and model truck).
These tow capacity ratings DIRECTLY define the relative difference in the amount of driveline stress a 3.42, 3.73, and 4.10 rear end can sustain.
Most folks I know would easily define a 8,000 - 9,000 lb. difference as "significant".
BTW, the surface on your ring gear looks a bit scored to me. We just changed the gear oil in our Ram Cummins' rear differential a few weeks ago. We change it every 20k (Ram recommends it be done every 20k for severe duty). 60k on the truck. No scoring.
