Has anyone changed out there differential gears?

Right now I have a 2001 4x4 3.55 gear with 17" tires.

I am planning on towing a trailer most of the summer and I am thinking about changing out the gears to maybe 4.10 if I keep the 17" tires.

Has anyone done this and if so how much of a difference does it make while driving.

What size are the differentials front and rear in the supercrew. I am wondering if maybe someone makes a gear inbetween the 3.73 and 4.10 like maybe a 3.93 or so.

 

All I can say is I want to really bad even though on my 4x4 it is going to cost close to $1,500!!!!!!

If you do a search you will find a lot of talk about this in the SuperCrew forum as the 3.55 gears, well, suck with any tire much larger than 31"

 

The 3.73 is the gear you want, it's a good match for the 17" tires. You will have to change the front gears along with the rear gears and it gets expensive. I would say that is why the 03 are build with the 3.73 axle.

You could also go with smaller tires and have the dealer adjust the speedometer.

 

I had 3.73's in my 99 Scab and the difference was very noticable compared to my 02 Screw with 3.55's. Offline acceleration, towing, holding 4th going up a hill, etc....everything was better with the 3.73's.

I thought I might avoid the headache by trading my 02 in on an 03 when the 04's are coming out (don't think I like the 04), and the 03's will be like $10k off sticker. However, this may end up costing $5-6k more due to low trade in values. I have since decided at 30k miles to go to 285/17 tires and 4.10 gears...this would probably equate to the same as 265/17's and 3.90ish gears. Probably a very strong combo. I haven't researched who sells what and what they cost yet, so if you find out some info please post. Luckily, I have a buddy that does this stuff for a living and will do the swap labor free!

 

I thought about the 3.73 gears but it seems to me that running 3.73 gears with a 17" tire/wheel combo (with the 265 tires) would be the same as the original 3.55 16" wheel tire/combo.

Wouldn't it be almost the same to run the 4.10 gears with the 17" 265 tire combo compared to a 3.73 16" tire/wheel combo (stock size tires)?

I think if I change the gears from my 3.55 to 4.10 it will raise my cruising rpms about 300rpm depending on my speed.

I am not sure what to do. I was hoping that maybe someone here has 4.10 gears installed and they could tell us how well it works in everyday driving vs. towing in OD and 3rd gear.

 

Does anyone know what size the front and rear differetials are? I want to start looking around to see what gears are available.

I think the rear is a 9.75 or 10.25 (I forget the brand name, I know it isn't dana)

Is the front a 8.8 or maybe a dana 44?

 

I don't know, here are some links:

https://www.f150online.com/forums/sh...ght=gears+4.10

https://www.f150online.com/forums/sh...ght=gears+4.10