Gear Swap
Mountain Pass
Joined: Jan 2018
Posts: 202
Likes: 3
From: Rancho Cucamonga
So you have a diesel then I assume? That's changes things, diesels have a lower rpm operating range so they need higher (numerically lower) gears than a gas engine. I would do the power upgrades first then decide if you need to regear or not. I wouldn't run any lower than a 4.30.
Senior User
Joined: Sep 2018
Posts: 157
Likes: 2
I was just going over details with my dealer. They said that the gear swap will void my powertrain warranty. Does this sound right? I cant see how it would being that I am switching to gears which are a factory option.
Senior User
Joined: Oct 2017
Posts: 111
Likes: 1
I’m sure the tranny is tuned for each gear setup from the factory so if you change that, I can see where it screws your warranty.
When I had mine done I was sure to tell the shop to keep everything as factory looking as possible, for that very reason. I mean, drivetrain parts fail, but a well built rear end should last a long, long time. And how are they ever going to know you changed ratios without pulling the diff cover and really doing their homework?
When I had mine done I was sure to tell the shop to keep everything as factory looking as possible, for that very reason. I mean, drivetrain parts fail, but a well built rear end should last a long, long time. And how are they ever going to know you changed ratios without pulling the diff cover and really doing their homework?
Senior User
Joined: Sep 2018
Posts: 157
Likes: 2
The problem is that the Ford dealer would be doing the work so I'm sure that they would put it in the computer system for every other dealer to see. If that's the case, I'll keep searching for a good 4x4 shop that can do the work.
Senior User
Joined: Sep 2018
Posts: 157
Likes: 2
That's what I was thinking. I priced it out with the dealer because it seems that they are the only ones that can get 4.30 gears for the Dana M275. The only 4x4 specialist in the area went out of business. I'll keep searching for a garage and keep you guys posted
Senior User
Joined: Sep 2018
Posts: 157
Likes: 2
I'm not going with 35s. I have 31s on it now. If I have to get bigger tires I'd go with 33s at the most.
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Logistics Pro
Joined: May 2017
Posts: 3,523
Likes: 483
From: Southern OH
31s? I didn't know they still came with tires that small, you definitely don't need a gear swap for those unless you just want more torque, do you have a diesel or gas engine?
Mountain Pass
Joined: Apr 2018
Posts: 143
Likes: 3
I’ve contacted many places including ford dealers about putting 4.30 gears in my 2018 f350 6.2. I can’t even get a quote from anyone. Everyone looks at me like I’m crazy. But that bumps the towing capacity up from 12,200 to 15,500 for my truck. At least in paper. That puts this truck in the sweet spot for most 5th wheel campers gvwr ratings.
Senior User
Joined: Sep 2018
Posts: 157
Likes: 2
I’m sure the tranny is tuned for each gear setup from the factory so if you change that, I can see where it screws your warranty.
When I had mine done I was sure to tell the shop to keep everything as factory looking as possible, for that very reason. I mean, drivetrain parts fail, but a well built rear end should last a long, long time. And how are they ever going to know you changed ratios without pulling the diff cover and really doing their homework?
When I had mine done I was sure to tell the shop to keep everything as factory looking as possible, for that very reason. I mean, drivetrain parts fail, but a well built rear end should last a long, long time. And how are they ever going to know you changed ratios without pulling the diff cover and really doing their homework?
Logistics Pro
Joined: Apr 2017
Posts: 3,674
Likes: 51
From: SoCal
Yes, diesel. My "common sense" thought process was a new ratio would be better for acceleration and overall MPG gain. However, I could be wrong. I know if I delete and tune, I will have plenty of power. Just wasn't sure if the power would affect what gear ratio I should change to.
Elder User
Joined: Dec 2018
Posts: 652
Likes: 5
From: Katy Texas
This..... if you regear you REALLY need to tune the truck for the gear swap. I think thats where dealerships will get you. If you are using factory abailable ratios on a truck with oem available wheels and tires, i dont see how they could void your warranty so long as you used the oem ratio and had the oem tune for that ratio. You could always contact ford directly and try and find out. Dealerships like changing oil and selling tires. Rear gear ratio swaps not so much. And those of you that are 4x4 dont forget you have to do the front too.