Gear swap

McBroom · Jan 18, 2021

Im thinking about swapping my 2WD 3.21 open diff to a limited slip with either 3.55's or 4.10's all from Matt @moesperformance
Im gonna keep the same tire size(stock).
My question is speedometer and fuel mileage.
I drive like I'm 90 on Sunday. I do watch my fuel mileage very closely.
Currently I avg about 18 city and 23 hwy.

Wife n I plan to buy a 25' TT and want the pulling power. The trailer will be close to max payload when loaded. No the trailer is not up for discussion!!
I'll only be hooked up to it occasionally 2-3 times a month.
Everything else is local city driving.

Black 20 Ram

Quyonmob · Jan 18, 2021

Forget 3.55 and go straight to 4.10. 3.21 to 3.55 isn’t significant enough for the cost.

Fast69Mopar · Jan 19, 2021

McBroom said:
Im thinking about swapping my 2WD 3.21 open diff to a limited slip with either 3.55's or 4.10's all from Matt @moesperformance
Im gonna keep the same tire size(stock).
My question is speedometer and fuel mileage.
I drive like I'm 90 on Sunday. I do watch my fuel mileage very closely.
Currently I avg about 18 city and 23 hwy.

Wife n I plan to buy a 25' TT and want the pulling power. The trailer will be close to max payload when loaded. No the trailer is not up for discussion!!
I'll only be hooked up to it occasionally 2-3 times a month.
Everything else is local city driving.

Black 20 Ram

My choice would be to go with the 4.10's and be done with it. You won't regret the choice. It will only make the truck more enjoyable to drive and towing will be a night and day difference.

Musky Mike · Jan 19, 2021

4:10s. but also realize your highway MPG is going to take a hit. Rancho and Hypertech (I think they maybe the same unit with different company logos on it) make a unit to reprogram the speedometer. There are youtube videos on how to use it. Your eddy shows a 2018 2500 4x4, but you said it was a 2020. Is the 2020 a 1500 or 2500? I ask because, although much more expense, a dealer install of a factory ratio would retain the powertrain warranty. Just something to think about. 3:90 would be factory for a 1500.

-- On a side note, the 3:21s with the 8 speed may pull the trailer fine if you "drive like I'm 90 on Sunday". Could be worth to make a couple trips with the trailer and stock gearing and see if you're satisfied with the performance.

McBroom · Jan 19, 2021

Musky Mike said:
4:10s. but also realize your highway MPG is going to take a hit. Rancho and Hypertech (I think they maybe the same unit with different company logos on it) make a unit to reprogram the speedometer. There are youtube videos on how to use it. Your eddy shows a 2018 2500 4x4, but you said it was a 2020. Is the 2020 a 1500 or 2500? I ask because, although much more expense, a dealer install of a factory ratio would retain the powertrain warranty. Just something to think about. 3:90 would be factory for a 1500.

-- On a side note, the 3:21s with the 8 speed may pull the trailer fine if you "drive like I'm 90 on Sunday". Could be worth to make a couple trips with the trailer and stock gearing and see if you're satisfied with the performance.

I haven't changed my profile bio yet but its a 2020 1500 lonestar lvl 2 2wd

Black 20 Ram

Daw14 · Jan 19, 2021

RainDesert · Jan 19, 2021

I would talk to my dealer about having the factory 3.92 gear set installed. When I looked into this on a previous truck it really was not going to cost much more, and you can have everything programmed correctly to match the new gearing.

Farmer Fran · Jan 19, 2021

What motor?

And I am in the camp of having the dealer do the install if it retains the warranty.

CG2742 · Jan 19, 2021

McBroom said:
Im thinking about swapping my 2WD 3.21 open diff to a limited slip with either 3.55's or 4.10's all from Matt @moesperformance
Im gonna keep the same tire size(stock).
My question is speedometer and fuel mileage.
I drive like I'm 90 on Sunday. I do watch my fuel mileage very closely.
Currently I avg about 18 city and 23 hwy.

Wife n I plan to buy a 25' TT and want the pulling power. The trailer will be close to max payload when loaded. No the trailer is not up for discussion!!
I'll only be hooked up to it occasionally 2-3 times a month.
Everything else is local city driving.

Black 20 Ram

I have. 4.10 from moes. The moes one they sell and master bearing kit if you’re interested. Priced to sell. New in box

McBroom · Jan 19, 2021

Farmer Fran said:
What motor?

And I am in the camp of having the dealer do the install if it retains the warranty.

5.7 CCSB

Black 20 Ram

McBroom · Jan 19, 2021

CG2742 said:
I have. 4.10 from moes. The moes one they sell and master bearing kit if you’re interested. Priced to sell. New in box

I'll send you a pm this evening

Black 20 Ram

Musky Mike · Jan 19, 2021

McBroom said:
I haven't changed my profile bio yet but its a 2020 1500 lonestar lvl 2 2wd

Black 20 Ram

Sweet ride.

mikeru · Jan 19, 2021

McBroom said:
I haven't changed my profile bio yet but its a 2020 1500 lonestar lvl 2 2wd

Black 20 Ram

Damn, I wish gas prices were that low where I live. Just because I'm curious, why didn't you buy a truck with the 3.92 gearing in the first place?

McBroom · Jan 19, 2021

mikeru said:
Damn, I wish gas prices were that low where I live. Just because I'm curious, why didn't you buy a truck with the 3.92 gearing in the first place?

Couldn't find 1. And the ones I did find weren't in the price range and were 4x4.

Black 20 Ram

Pull Ya · Jan 19, 2021

Claud--I think the 4.10's would be a little too low with the 8-speed trans, especially with a 2WD. I'd suggest 3.92's. I'd also suggest installing a limited-slip at the same time. I'd also talk to Matt and get his recommendation
Jay

McBroom · Jan 20, 2021

Pull Ya said:
Claud--I think the 4.10's would be a little too low with the 8-speed trans, especially with a 2WD. I'd suggest 3.92's. I'd also suggest installing a limited-slip at the same time. I'd also talk to Matt and get his recommendation
Jay

Jay I've been emailing with Matt. LS is in the cart already. I agree on being too low. It's not a hot rod. Don't want to loose too much in fuel mileage either. I just want a little more pulling power in the torque range when pulling a travel trailer. One reason I was thinking 3.55 and 3.92s
The 3.55s will add a little but not really sacrifice fuel mileage.

Black 20 Ram

McBroom · Jan 20, 2021

mikeru said:
Damn, I wish gas prices were that low where I live. Just because I'm curious, why didn't you buy a truck with the 3.92 gearing in the first place?

That pic was taken back during the summer. Its about 1.889 right now

Black 20 Ram

Pull Ya · Jan 20, 2021

I think you'll be happier with the 3.92's. Power for pulling your trailer, yet good street manners and I think you'll be OK with the mileage. I get about 14-15 around town and about 20 on the highway------when I drive reasonably. The difference between the 3.21's and the 3.55 isn't that great.
Jay

McBroom · Jan 20, 2021

Pull Ya said:
I think you'll be happier with the 3.92's. Power for pulling your trailer, yet good street manners and I think you'll be OK with the mileage. I get about 14-15 around town and about 20 on the highway------when I drive reasonably. The difference between the 3.21's and the 3.55 isn't that great.
Jay

I'm sold Jay. 3.92s and a TruTrac it is.
This'll be the 1st and only mod to this truck. It's perfect otherwise.
Got the 1st oil change yesterday at 6700 miles

Black 20 Ram

Pull Ya · Jan 20, 2021

Tru Trac is the best of the best but I think it is more expensive than the stock limited-slip which is a pretty good unit if you don't beat the hell out of it. I think maybe Matt sells both the gears, limited-slip, and the install kit.
Jay

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