So I was going to lift 2010 f150 with a procomp 6" lift and run 35's under it. Then I started reading all the fourms saying you need to re gear your front and back axel. Mine has the 3.55 and so do the ones for sale at the dealership. Why would the spend 6 grand on something if the job isn't done right and warranty it also if its not that big of a deal. Also I have never heard of anyone tearing up there tranny due to larger tires and a lift. Im no gear head but its not adding up on why I would spend the extra for new front and rear end. Someone help please!*

 

I'm pretty sure one of the main reasons you would re-gear is so that you don't lose power and get some mileage back. I could be wrong though.

 

Basically after the tire swap, you would have between a 3.14 and 3.25 final gear ratio after the tire swap, depending upon the current tire size, 31 or 32". At those ratios the truck would be a dog. Your truck would also have too low of RPMs when in overdrive causing it to constantly shift back and forth, especially on small hills and while driving into a headwind. That will eventually damage the transmission. To get back to a 3.55 after the swap, you would need to put in 3.88 to 4.01 gears. Closest gears available to those are 3.73 or 4.10. However, you are also going to have a weight penalty from the larger tires. Bare minimum gears to go to are 4.10. You can check the figures here.

http://www.4lo.com/calc/geartire.php

 

Gear swap is not necessarily something you need to do in my ipinion.

My first truck - 2001 f150 ext cab sport 4x4 w/ 5.4L. 6" fabtech lift w/ 35s. Bought truck stock with 35k miles. Put lift on around 60k and sold truck with 180k miles. Routine maintenance n trans flushes n not a single problem. Left stock gears - not sure what it had. 3:55 or 3:73.

Towed snowmobile trailer, boat, and atv trailer all the time. Did i notice a loss of power, sure, but not noticable where i needed to swap gears.

New truck i just got - 2010 fx4 screw w/ 5.4L. 6" lift and 20s w/ 35s. Bought truck with lift and tires. No gear change as far as i know. Speedo is off after 50mph so i believe gears r stock. Truck runs good. I dont beat on it n havent towed with it yet. Def feels faster n more power then my other truck. I think motor has a few more hp then my old 5.4.

35s would be max id go without a gear swap. One thing i noticed when looking for a new truck. 2004+ Is that there were alot of lifted trucks with 37s n no mention of a gear swap. Also noticed a few with rebuilt or new transmissions with 100k or less miles. My opinion is that 37s r too big without swapping gears. I could be wrong with the newer 5.0, 6.2, or ecoboost. Those motors make good power n may be ok.

Just my 2 cents.

 

I think the key is in how you intend to use the truck.

How often are you towing, and what are the spec's on what you are towing?
Do you live around hills?
Are you planning on offroading? If so, how often?
Is acceleration and drag racing in your blood?

I wouldn't hesitate to put 35" tires on my 2012, espeically with the selectshift transmission. If I was towing or in hills, locking out 6th gear is a great feature.

If you are heavy into offroading, I'd regear. My Jeep JK is running 35" tires, but with 5.13 gears. Why? Because its purpose built for off roading.

For the cost of regearing, I'd strongly consider trading for a 3.73 or 4.10 equipped new(er) F150. Then you get warranty, and a new truck too!

 

During the summer I frequently tow my 23ft bowrider, 5k pounds or so. I don't off road regularly with it, but I do take occasional trips to the OBX on the beaches, occasionally play in the mud, and sometimes venture out in some deep snow. I do not notice any major power loss or issues, but I do have the 3.73 gears, along with the 5.4, which is much better coupled with the new transmission than my 01 on 33's was. Dont get me wrong, while towing I notice its back there, and hills cause it to pop out of overdrive, but it would probably do that, maybe not as much, without the lift and 35's. Like the others I wouldn't push it past 35 or 37's without regearing though. I think the new 6speed tranny and the 3.73's definitely help the situation out. I think 01 had 3.55's and 33's,and i put a lot of miles on it with no issues.

 

On my 07 I had a 5.4 with 3.55's that was troyer tuned and when I put on 35's I noticed a slight difference in how it pulled from a stop, but nothing major. On the 09+ with the 6 speed auto, you have a much deeper first gear than the old 4r75 had so you can go to a bigger tire with any noticeable difference in performance. But if you do go with tires bigger than 35" then you might want to consider re-gearing. For the cost of a re-gear, you need to go at least two steps up to make it worth the money spent. So if you have 3.55, then go to at least 4.10, the 3.73 is too close to what you have now, you won't notice any difference.

 

Just go for it. You will love the look. As most of us stated you should be fine with 35s. If you do notice a big difference a cheaper solution then a gear swap would be a programmer. That may help give it some xtra powee n can also put in correct tire size so speedo is accurate. Never had a programmer on old truck but do plan on getting one for me new truck.

 

If you want the truck to haul *** to the point where it not only looks cool with the lift and big tires, a 4.56 is in the list of mods to consider. The difference in the 3.55 and 4.56 is massive, and noticeable on both the foot and the mileage.

Do you want to feel some power in the lifted truck, and have a shot at keeping up with that wee 'lil civic that pulls up to you at the lights? Those tires and stock gears are going to see you in a dog fight with a 4 banger honda. 4.56 however..... see ya! Zero comparison.

Do you want all show and no go? When I put my 34.5 inch Nitto Trail Grapplers on, I can instantly feel a power difference from the winter blizzaks I run. Same tune, just heavier rubber. I kept my 3.73's, but only because I'm cheap, and can't part with the extra cash to re-gear. I couldn't imagine the power diff on a 3.56.

 

Well the problem might not be the gearing, It'll be searching for bearings and other parts to make it work. I'm currently in the middle of swapping 3:55 gears for 4:56 motive gears. My buddy was a ASE certified mechanic ford till a couple years ago and has done countless gear swaps before.

My truck:
2010 FX2 Supercrew Blue Flame 4.6 3v and 8.8/3:55,305/60r18
suspension: SVT Raptor lowers, uppers, 2.5 Fox "Raptor" shocks and coils\
Edge Evo CS tuner
Fiberworx front fenders and fiberglass bed

The problem started with the pinion bearing. It HAS to be the same as Ford uses which is a KOYO ST4190LFT. An 8.8 from 08 and below WILL NOT WORK, too small. So my trucks torn apart and I have to overnight this stupid bearing from ohio some place.

We press this bearing in to the motive pinion with lil shim that came off the stock gear. turns out, when we go to tighten up the carrier, the pinion and ring gear spin fine all the way till you have to tighten them and the pinion will rub against the carrier body. The set up has too much pinion depth. The carrier is pretty well marked upon closer inspection and i dont believe the lil .013 shim will fix this...if this does end up working, the pinion gear is gonna HELLA close to the carrier body. We had to shut er down cause he's on nights and ill be going on later tonight as well. Day 2 down and all we did was get this bearing in. I was looking on the net if anyone else has come across this same issue and found this thread. Regearing is one of the best things in the world...I'm just trying to work out the bugs here and pass them along to the rest of the world. sorry for jacking your thread man, but i would'nt want you to get held up like in my case.

 

I do not believe the select shift was available until 2011. I know they weren't in 09 when I bought mine. On mine, you cannot lock out any gears. Even current models do not all have the select shift, especially those like the XL and STX.
Also the speedometer (assuming a stock 31.5" tire) will be off by almost 8mph. That will affect transmission shifts without a programmer. Without knowing what the stock tire size it is also very hard to tell just how high his gear ratio will be after the change. As far as what I calculated using 31" and 32" stock tires, Ford does not even offer a ratio that high, probably for a reason.

 

Well i understand my truck is not going to be in the next Fast Furious. Just test drove the one dealership with the 3.55 with the 35's and it still had the power I needed. I have nothing to tow and don't see me getting anything to tow in the near future. Stock tires were 275's. I understand my truck will lose a little power bit judging from my test drive it'll still be perfect.

 

Just make sure you get the speedo/odo corrected for the big tires, either with a reflash or a programmer.

 

Bookmarked.

As I'm fairly certain the OP will return at some point complaining aboot performance ( the aforementioned ricer Civic / Lada sucking out the headlights of his dawg of a truck ), and / or looking fer help on how to improve the mysteriously poor mileage.

Yeah - the 6R80 does have a nice deep 1st gear - but that doesn't matter for the rest of the ratios - ALL the ratios will be affected by a tire diameter increase of this size.

I vote fer 4.10's at a minimum - 4.56's if yall want to get some jam. And definitely a Custom programmer ( so add anudder ~$400 to yer budget). Gotta pay to play - unless ALL you want is a Poser truck

Sorry - just the way I see's it. Don't git bent discussin' trucks on an ADULT truck site.

 

I have a 6" Procomp lift and 35's on my 09'. I have no complaints but re-gearing is on the list of upgrades down the road. The mileage is not great with 3.55 gears and as far as performance, how I use the truck it's definately not a dog. Overall I'd say go with the lift and decide on gears later if you aren't happy with the performance.