I know this isn't the right thread to be posting this, but you guys have always been a huge help in everything I needed so I'm just curious. I really NEED to upgrade to 4.10's. My truck runs great, but my buddy with 3.73's always takes off quicker and I always end up pulling him at the end. My question is where are you guys getting your gearings and what kind of prices am I looking at??? Thanks

 

I hate my 3.55s to, I wish i had the 3.73LS instead of the 3.55LS

 

I saw an ad where Motive Gear makes a 3.90. Would that make a good place to go from 3.55 and still keep the rpm's from killing gas mileage? Is there a noise issue with the Motive Gear 3.90?
Has anyone on here installed 3.90s? All I see is 4.10.

 

4.10s are pretty steep if it is a daily driver with any regular freeway mileage.

I have the 3.73LS and wouldn't want anything higher. I agree though that a jump from a 3.55 to a 3.73 probably isnt worth the money. That is a pretty tough situation especially if decent highway milleage is a concern

 

Since your truck is a 2wd, it came with 30" tires. With your current 33" tires, 4.10s would put you about 100RPM higher at 75mph. That shouldn't make much of an impact on highway mileage, and may actually increase mileage if your in hilly terrain.

As far as where to get the gears done, you can try the dealership and see if they do it reasonably. If not, ask around town and find a trusted shop to do it. It should only cost $600-800 including parts, maybe cheaper if you get lucky.

 

Having those size tires (285/70/17), I would go with the 4.10's. I have the same size tires and found that 4.10 will get me back how the gearing was stock. I also have the 3.55LS and plan on going to the 4.10 soon to get some low end back. I have found pricing for one axle (4X2) around 600$ -$800 range. Those size tires are about a 33" tire, check out this chart to see where you want to be.... http://www.rbroffroad.com/gearcalc.htm

 

tigga

I know this flies in the face of what was posted already, but I'm running a 4.10 ratio. I upgraded from the stock 3.55s when I had a pinion bearing go bad two years ago. I have noticed NO reduction in fuel economy since going from 3.55s to 4.10s. By the way I'm running 245 70R16 tires - basically stock. I average 16 mpg over winter with me having a heavy foot at most stop lights. I can get 1 mpg to 1.5 mpg more if I drive for economy. I certainly like the extra torque multiplication I get from the 4.10 gears.

Just for your info: I got the entire 4.10 gear assembly including the limited slip clutches already put together for $400+ from Ford. Just the gears themselves can be had for less than half of that from Jegs, Summit. If you don't have limited slip, this would be the time to add that while you are doing the gears.

best of luck with whatever you decide

enb

My truck is a 2wd. Obviously 4wd requires gears changes on both ends of the truck.

 

Well, I do agree with some things said here -

For example, this is not the place to discuss this, it's the wrong section. That having been said, a few points:

4.10's are not even remotely "steep" for any of these trucks, IMHO - nor will that have a significant negative impact on fuel economy - unless you spend 90% of your time cruising at speeds of 80 mph or higher, you will not see a decrease in mpg - there are hundreds of posts here, and we have hundreds of customers who have done this, and virtually all of them see no negative impact on mpg. Most people who install them see either no penalty at all, or actually see a slight improvement in mpg due to less upshift/downshift cycles, and the engine being under a lighter load due to the increase in torque multiplication. It's just not that big a deal on a truck with 30" or taller tires, the rpm differential is not large enough to impact mpg in any significant way for 95% (or more) of their owners.

Changing from 3.55's to 3.73's is not worthwhile - a 5% change just is not worth the expense, unless maybe it's a pro racing scenario where you have to hit a certain rpm within a very tight range - for the street, forget it, changing from 3.55's to 3.73's is never worth it - go to 4.10's. these boards have hundreds of posts from those who have gone from 3.55 or 3.73 to 4.10, and the vast majority of them absolutely love it.

Just my .02 -

 

I want to go to 4.10 gears also... If it were a 5-speed I would not think twice about going to 4.30's.

 

I have 4.10s with 285/70/17s. It made a world of difference from the 3.55s. I wish I would have went with 4.56s.

As far as gas mileage. Everything I have done to my truck has netted me less mileage. Bigger tires, X-cal II and 4.10 gears with detroit locker. I am down atleast 2 mpg from where I started.

 

4.56s! Stock with 3.55s and 30 inch tires I did 14.8-15 in town. Then with the 20s, it went down to 13-13.5 in town. Now with the 4.56s and XCal2, 16.1 in town. Hoping for more between the Volant I installed today and getting rid of the damn winter blend gas soon!

 

I had Motive Gears in my Mustang and they make a decent gear but the difference from 3.90 to 4.10 is nothing thats why Ford doesnt make them. My personal opinion as the perfect gear would be 4.30s.

 

Anyone know if anyone makes a 4.30 for 4wd? reverse cut for the front diff?

 

I haven't seen any 4.30's in reverse cut. If your running 33" tires or less go with 4:10's that would be plenty of gear and you'll have plenty of brands to choose from.

 

Thanks Mike,

You fully covered my question before I could ask.