4.10's
 

Hey guys. Im thinking about putting in 4.10 s and had a few questions. Im wondering once i get the 4.10 s installed will i have to do a motor or tranny tune before i drive it away from the shop? I have 3.55s in now and im going from a 255/60[i think] to a 275/70/18 and also want a little more get up and go. Will going from 3.55 to 4.10 put any kind of unusual wear and tear on the truck since its a big change? Anyone who has done a gear swap happy with theirs/advice? Thanks.

Recomendations for manufacturers?
Ive heard the FoMoCo and Yukon. any others?

sorry, truck is a 08 xlt 4x4 screw

well your going to love some highway mileage, you don't have to do anything before leaving, your tach will be off though. if you got a tuner, it will be an easy fix though

I went from 2.73's to 4.10's in my car and the rpm only went up about 500.

I know its not the F150 but it certainly woke the car up.

Where does your Fords get their speedometer readings?


If it is anything like our Ram's, the reading is taken off a tone ring on the carrier, so the speedometer reading is only dependant on AXLE rotations, not DRIVELINE rotations. Ring and Pinion change will not affect the speedo reading on this type of setup. BUT, a tire diameter change will effect the AXLE rotations per mile, so you'd have to have your PCM recalibrated at the stealership to the new tire diameter, so it reads the proper amount of axle rotations per mile and the speedometer reads correct.

If it uses a sensor in the transmission for the speedometer (which I doubt being as new as it is) there may be a hall effect sensor or it could be a geared pinion, in which you'd have to change out the pinion for one with a different pitch(tooth count) to correct the speedo.

Not being familiar with the inner workings of the F150 this is just a few ideas to ponder, nothing to be taken as textbook. Im sure one of the experienced techs will chime in soon....

F-150 takes speed from the tranny.


Your speedo will be off since the PCM will still think you have 3.55 gears. so I recommend getting the PCM reprogrammed after you get the wheels + the gears...otherwise you'll need to reprogram it twice


otherwise, you don't need anything else done to the truck...the gears will actually make the motor/tranny do less work

thanks guys. any advice on manufacturers?

I went from 3.55 to 4.1 Ford Racing gears in my 2005 Screw, which also was sitting on 305/45/22s. It was a considerable change in off the line acceleration, but definitely didn't help in mileage. At freeway speeds the best MPG I could pull was maybe 15.

I averaged 12.3 with 90% city driving, and almost always fairly aggressive driving style. This was also on crappy California gas.

I put Motive gears in my car

Motive, Precision, Yukon, Richmond, all are good units I've used them all or installed them for others none have had any problems.

Make sure you put a Master Install Kit in with both front and rear axles, it has new carrier and pinion bearings, pinion seal, ring gear bolts (most do), GMC, crush sleeve, and pinion shims. It basically assures everything is fresh in the axles so you dont frag a bearing and eat up your new hypoid set. Plus all that stuff has to come out anyway so its the best time to make sure everything is of equal age so it all wears evenly and consistently.

Does each manufacturer make their own master install kit or is a general one you can get from a rear end shop? thanks

I went from 3.55 to 4.30 motive gears and I am running 305/40/22 which are right at 32" and I wished I would of went with 4.56 gears. I get 12.5-13.5mpg city with very aggressive driving and I get around 16mpg on the hwy cruising between 75-80mph around 2500rpm. I have gotten 17.5mpg on the highway cruising at 65mph which is right at 2k rpms

I just got my 4.56 gears (rear), install kit, Detroit True Trac in the mail today. I've gotta order some gears and install kit for the front, but I'm waiting to get my tax return.
A tuner is needed to fix the speedo and custom tunes would help with your tranny shifting with the new gear ratio. My gears are Ford Racing. I think most gear makers are good, its the proper install that is crucial. After install the 'break in' is important if you want them to last. The break in process is outlined well at randy's ring and pinion website. DO IT!

http://farm4.static.flickr.com/3567/...cd5ee0cb_o.jpg

What this smart person said..... :rocker:

I have the Tra-Tec No-Spin (Detroit Locker) in my 96 Ram. You will LOVE that thing!!! Gears and the Detroit were my best bang for the buck mods. Plus unlike some folks will tell you, you'll actually gain some mileage, depending on tire size. The Rams have a pretty steep OD coupled with stock 3.55 gears, too steep in fact, it lugs hard up hills on the highway and shifted out of OD alot, unloaded just cruising around 70-80. With the 4.10's the the truck never comes out of OD unless I have to punch it or manually shift out of OD. Once the "marvel" of all that newfound torque to the ground becomes old hat, your driving style will level back out to what it was before, and you'll actually see mileages should come up 1-2 MPG.

Had I known how to do hypoids back in the mid 90's when I bought my new 96 F-150, I'da kept that truck. Was a 5 speed I-6 300CID shortbox single cab in raven black with the metallic red lower half. It had 2.73 gears in the axle!! A set of 4.10's would have made that truck. Oh well that poor trucks in Ford heaven now, guy that bought it from the dealer after I traded it in wrapped it around a telephone pole a couple months later. Sucks because the truck was in better condition when I traded it in, then when I bought it new with 3 miles on the Odo. :rolleyes:

I just found a good rear end shop with a real good track record so i think im going to order the yukon 4.11s and get the troyer performance tune on an xcal 2 and do everything at the same time. Tax return money needs to kick in! Thanks to everyone for their input!!:beers: