Regearing 14thgen

[SpaceWhiteF150]

There’s some info on here about regearing but not one thread. I’m playing with the possibility of a rehear when I step up to bigger tires. If you’ve done it share your experiences!

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[SALEEN961]

I haven't re-geared my 2021, but I have replaced the front and rear carriers. Overall there aren't many substantial differences between doing this on a 2021, a 2015, or a 2009 F150, they are all very similar. The biggest difference that comes to mind is the importance of entering brake maintenance mode on the 2021+ trucks as this is different from all previous model year F150s.

I swapped out the stock 3.55 gears my 2014 came with for 4.10 gears and from a performance standpoint it was well worth it. My 2014 5.0 was very slow compared to my 2021 3.5EB, and the very long 2nd and 3rd gears of the 6R80 didn't help. With the 10R80 in my 2021, I'm less inclined to re-gear my truck because even with 3.55 gears, the gearing is better than my old F150 with 4.10s.

If you are going to swap out the gears yourself, make sure you fully understand what tools, bolts, seals, and shims with be needed, and make sure you budget enough time to get things perfect. If you go to a shop, make sure they have the tools needed to easily and quickly remove the inner pinion bearing from the pinion. If they don't, there's a good chance that they won't take the time to get everything setup correctly. The last thing you want is a frustrated tech with the wrong tools saying that a bad pattern looks good enough because he's flat rate and doesn't want to continue working for free.

 

[Calson]

There’s some info on here about regearing but not one thread. I’m playing with the possibility of a rehear when I step up to bigger tires. If you’ve done it share your experiences!

Start by calculating the change in the diameter, and hence the circumference of the new tires. When I did this for my prior pickup the difference was only 4% or too little to be a concern. I also had a great deal of low rpm torque with its diesel V-8 engine that produced peak torque at less than 1700 rpms or half that of most gas engines.

 

[pittman]

Re-geared my last truck to compensate for taller tires. Was the best money I ever spent. Gives you the opportunity to change to a different diff locker if you want too. Maybe add a Torsen to the front?

I'd guess it'd be less important with the 3.5L EB as the torque is so good and the 10R80 manages it well. Any other engine and I'd be thinking about it...

 

[ThumperF150]

I have re geared two jeeps to offset the larger tires and have been 100% happy each time. Build plans for my 2024 RCSB 4x4 5.0 include a level and 34” tires. I’m giving serious consideration to swapping the 3.73s for 4.11s. Rough initial calculations have me thinking this change will keep RPMs at 70 will be within 10-12 of stock and all shift points should be the same as well as the speedometer.

 

[ThumperF150]

Update: I ended up going with 35X11.50 tires and the numbers are pretty darn close to what I thought they would be in my previous post.

My speedo is about 10% off (Indicated 44mph at a GPS 40 mph). 3.73s to 4.11s is a 10% change as well. So.... if my calculations are correct, this should put my final gearing back to stock or within 1-2%. I can live with that amount of error.

I finally have all of the required parts, Yukon 4.11 gears (because they are the only company I could find that makes 4.11s for both the 9.75 and 8.8) Torsen front LSD that comes in the Raptor, Lube Locker gaskets and new diff covers. I went with the Dana Spicer rear cover and then bought a second factory diff cover for the front and welded in a lower drain plug to make life for future me easier. I have a call in to my guy to get on the calendar to have all this stuff installed, hopefully in the next two weeks or so.

Wish me luck.

 

[FaaWrenchBndr]

Update: I ended up going with 35X11.50 tires and the numbers are pretty darn close to what I thought they would be in my previous post.

My speedo is about 10% off (Indicated 44mph at a GPS 40 mph). 3.73s to 4.11s is a 10% change as well. So.... if my calculations are correct, this should put my final gearing back to stock or within 1-2%. I can live with that amount of error.

I finally have all of the required parts, Yukon 4.11 gears (because they are the only company I could find that makes 4.11s for both the 9.75 and 8.8) Torsen front LSD that comes in the Raptor, Lube Locker gaskets and new diff covers. I went with the Dana Spicer rear cover and then bought a second factory diff cover for the front and welded in a lower drain plug to make life for future me easier. I have a call in to my guy to get on the calendar to have all this stuff installed, hopefully in the next two weeks or so.

Wish me luck.

sounds about right…….
Be sure to ask about the gear break in period and what mileage to change diff oil.

 

[ThumperF150]

sounds about right…….
Be sure to ask about the gear break in period and what mileage to change diff oil.

On both of my jeeps they said no highway or towing for 500 miles. They both recommended multiple heat cycles. So that’s what I did and never had a problem.

My buddy did not know, swapped his gears, went on a trip and destroyed the first set. Doubt they were meshed properly but the high/prolonged initial heat did not help. He broke in his second set and has not had any problems.

 

[SpaceWhiteF150]

Update: I ended up going with 35X11.50 tires and the numbers are pretty darn close to what I thought they would be in my previous post.

My speedo is about 10% off (Indicated 44mph at a GPS 40 mph). 3.73s to 4.11s is a 10% change as well. So.... if my calculations are correct, this should put my final gearing back to stock or within 1-2%. I can live with that amount of error.

I finally have all of the required parts, Yukon 4.11 gears (because they are the only company I could find that makes 4.11s for both the 9.75 and 8.8) Torsen front LSD that comes in the Raptor, Lube Locker gaskets and new diff covers. I went with the Dana Spicer rear cover and then bought a second factory diff cover for the front and welded in a lower drain plug to make life for future me easier. I have a call in to my guy to get on the calendar to have all this stuff installed, hopefully in the next two weeks or so.

Wish me luck.

Nice I’m a bout to do the same!

 

[The_Auto_Tech]

Update: I ended up going with 35X11.50 tires and the numbers are pretty darn close to what I thought they would be in my previous post.

My speedo is about 10% off (Indicated 44mph at a GPS 40 mph). 3.73s to 4.11s is a 10% change as well. So.... if my calculations are correct, this should put my final gearing back to stock or within 1-2%. I can live with that amount of error.

I finally have all of the required parts, Yukon 4.11 gears (because they are the only company I could find that makes 4.11s for both the 9.75 and 8.8) Torsen front LSD that comes in the Raptor, Lube Locker gaskets and new diff covers. I went with the Dana Spicer rear cover and then bought a second factory diff cover for the front and welded in a lower drain plug to make life for future me easier. I have a call in to my guy to get on the calendar to have all this stuff installed, hopefully in the next two weeks or so.

Wish me luck.

Any reason for the Dana rear cover specifically? I just finished my gear swap/LSD install and just tossed the factory cover back on. Figured I'd run it through break in and then replace the cover since I'll need to drain all the fluid and clean it out anyways.

 

[ThumperF150]

Any reason for the Dana rear cover specifically? I just finished my gear swap/LSD install and just tossed the factory cover back on. Figured I'd run it through break in and then replace the cover since I'll need to drain all the fluid and clean it out anyways.

No.

I wanted a drain plug and liked the look of it. Same as the Ford Performance cover but about $100 cheaper.

 

[The_Auto_Tech]

No.

I wanted a drain plug and liked the look of it. Same as the Ford Performance cover but about $100 cheaper.

Is this the one you got? I like the finish on it, it's not too flashy but not too bland.

https://danaproparts.com/i-30497675...ear-axle-compatible.html?ref=category:1389904

 

[ThumperF150]

Is this the one you got? I like the finish on it, it's not too flashy but not too bland.

https://danaproparts.com/i-30497675...ear-axle-compatible.html?ref=category:1389904

Yes but that one is for an 8.8. My rear diff is the 9.75.

 

[The_Auto_Tech]

Yes but that one is for an 8.8. My rear diff is the 9.75.

Ok gotcha, I was gonna say, I haven't found one for the 8.8" yet like that. lol

 

[vst]

Update: I ended up going with 35X11.50 tires and the numbers are pretty darn close to what I thought they would be in my previous post.

My speedo is about 10% off (Indicated 44mph at a GPS 40 mph). 3.73s to 4.11s is a 10% change as well. So.... if my calculations are correct, this should put my final gearing back to stock or within 1-2%. I can live with that amount of error.

I finally have all of the required parts, Yukon 4.11 gears (because they are the only company I could find that makes 4.11s for both the 9.75 and 8.8) Torsen front LSD that comes in the Raptor, Lube Locker gaskets and new diff covers. I went with the Dana Spicer rear cover and then bought a second factory diff cover for the front and welded in a lower drain plug to make life for future me easier. I have a call in to my guy to get on the calendar to have all this stuff installed, hopefully in the next two weeks or so.

Wish me luck.

How do you like the 4.11 I just put the same size tires on and I have 3.31’s and im thinking of re gearing. Do you have a 5.0?

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