Rear Gear build

[bcso0416]

I have a 2020 4X4 1500 with the e-Torque V6 and the 3.21 rear gear. When I purchased it new my thought was fuel mileage (19/24 mpg). It came with the tow package and listed the truck at 6800 lbs. towing and 1880 lbs. payload. After getting all the data on my truck RAM suggests that only 6400 lbs. should be the maximum towing. Now, most of the smaller campers that I have been looking at with tandem axles will weigh in between 4500 and 5500 lbs. I know I have to consider all the weight of everything so I was thinking about the rear gear being changed. My same truck, if it had been built with the 3.55 gear would have a 7800 lbs. towing and a suggested maximum of 7400 lbs. not changing the payload or the listed fuel mileage (19/24mpg). The optional price for the 3.55 in place of the 3.21 gear from the factory is only $95 bucks. So that got me to thinking if the rear gear could be changed out, which I would let the dealership do, to keep any warranty issues from popping up? Does anyone know if it's that simple to buy the 3.55 gear from the dealership and have their service dept. swap it it out or is it more complicated than that and not worth the trouble? I apologize if this is in the wrong place to ask and appreciate all reply's.

 

[Ellisstrong]

Being 4x4 you would need to r

I have a 2020 4X4 1500 with the e-Torque V6 and the 3.21 rear gear. When I purchased it new my thought was fuel mileage (19/24 mpg). It came with the tow package and listed the truck at 6800 lbs. towing and 1880 lbs. payload. After getting all the data on my truck RAM suggests that only 6400 lbs. should be the maximum towing. Now, most of the smaller campers that I have been looking at with tandem axles will weigh in between 4500 and 5500 lbs. I know I have to consider all the weight of everything so I was thinking about the rear gear being changed. My same truck, if it had been built with the 3.55 gear would have a 7800 lbs. towing and a suggested maximum of 7400 lbs. not changing the payload or the listed fuel mileage (19/24mpg). The optional price for the 3.55 in place of the 3.21 gear from the factory is only $95 bucks. So that got me to thinking if the rear gear could be changed out, which I would let the dealership do, to keep any warranty issues from popping up? Does anyone know if it's that simple to buy the 3.55 gear from the dealership and have their service dept. swap it it out or is it more complicated than that and not worth the trouble? I apologize if this is in the wrong place to ask and appreciate all reply's.

Being 4x4 you would need to change the front too and that makes it much more expensive from my understanding

 

[Moosefire66]

I imagine it's fairly labor intensive, both front and rear will have to be done as mentioned, but to replace a gear set you have to pull the brakes all apart in order to move the axle shafts, then replace the gears, testing and adjusting shims so that it meshes properly, then reinstall them. If I was to do it (I also have the v-6 with the 3.21) I would take it to a dedicated gear shop. It's cheaper and most likely faster than going to the dealership.

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[Hasti17]

I have a 2020 4X4 1500 with the e-Torque V6 and the 3.21 rear gear. When I purchased it new my thought was fuel mileage (19/24 mpg). It came with the tow package and listed the truck at 6800 lbs. towing and 1880 lbs. payload. After getting all the data on my truck RAM suggests that only 6400 lbs. should be the maximum towing. Now, most of the smaller campers that I have been looking at with tandem axles will weigh in between 4500 and 5500 lbs. I know I have to consider all the weight of everything so I was thinking about the rear gear being changed. My same truck, if it had been built with the 3.55 gear would have a 7800 lbs. towing and a suggested maximum of 7400 lbs. not changing the payload or the listed fuel mileage (19/24mpg). The optional price for the 3.55 in place of the 3.21 gear from the factory is only $95 bucks. So that got me to thinking if the rear gear could be changed out, which I would let the dealership do, to keep any warranty issues from popping up? Does anyone know if it's that simple to buy the 3.55 gear from the dealership and have their service dept. swap it it out or is it more complicated than that and not worth the trouble? I apologize if this is in the wrong place to ask and appreciate all reply's.

its Pandoras box, its a $95 option BEFORE the trucks is built when they have both final drives setups available. think of it this way, if its $2000 for the 3.21 in terms of the money it costs to put it in, thats included in the base price of the truck. so its only 95 Bucks because your only paying for the DIFFERENCE between the included 3.21 cost and the cost to sub it for a 3.55. and again the cost in small because they are mounted before the body ever meets the frame.... so its alot simpler for the factory to slap one in. it will set you back a couple thousand at least. youll pay the Full price for the new final drive and the price to disassemble and reassemble the truck.

 

[ferraiolo1]

Your dealership most likely will not do the swap. And it doesn’t change your legal towing capacity. It’s generally 2-3000 for a 4wd gear change at a off-road shop.

And yes it wild affect your differential warranty


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[bcso0416]

I kind of figured that it would be more complicated than just a simple swap. I will just have to make do with what I have. Thanks for your advise and time to reply.

 

[GKIII]

It'd be cheaper to trade in your current truck.

 

[BowDown]

Diff rebuilds are about $850-950 at a shop, I paid $850 a few years back at shop, 4 Wheel parts, for a rebuild. A rebuild is the same price as a gear swap as you're doing the same work minus taking the ring gear off the carrier which is 5 minutes of work. Obviously you'll need the front done as well so $16-1800 in labor, motive gears are about $250 so 2 sets or $500. You could be in ab out for $2100-2300 plus a speedo calibration change at the dealer, $100 at best.

I'd suggest finding a 4WP store or similar and getting a labor quote.
Also 2 rebuild kits, about $100 each

 

[BowDown]

It'd be cheaper to trade in your current truck.

No it wont

 

[BowDown]

I kind of figured that it would be more complicated than just a simple swap. I will just have to make do with what I have. Thanks for your advise and time to reply.

Its not a big deal, a shop can easily handle this in 1 full day or a day and a 1/2

 

[Glenn54]

I called a shop that specializes in differentials for an estimate to replace my open diff to a limited slip. The quote was $1,500.