I have a 2005 FX4 and I was wondering would I HAVE to regear with 37s? I won't be doing and towing and I'm not worried about the speed or acceleration. And of course eventually I will upgrade to 4.56s. I just don't want to mess anything up in my truck. And yes I know there's a search function and I used it but didn't come up with anything but people saying they "recommended" regearing I want to know
If it's something I have to get or can I slide by for a few months with stock fx4 gearing ratio thanks

 

U will probably be okay with the stock 3.73. Wouldn't recommend running that for long as the added strain will take a toll on your transmission. Do u have a programmer so that u will be able to adjust tire size and shift points?

 

I don't have a programmer. How long would I be safe to run the 3.73s?

 

if you even have to ask that question its probably not a good idea.

 

Lol here you go again

 

People run 35s with 3.55, which would be equivalent to 3.73s with 37s. U may be safe for a while, or it may finish your transmission, there is no way to tell. I can tell u that a 1500 dollar gear upgrade is cheaper than a new transmission. Up to u if u want to test your luck. If u don't Off road or tow much, u may be fine, but it just seems like u should do it right if you are getting all the other work done.

 

if I was to give the dealer my vin would they be able to look what gears came with my fx4? it's a 2006.. I have 35s with 20x10s with the original gears and I think it's a complete nightmare between the sluggish power and mpg.. always wondered if a programmer would be a temp fix prior to replacing with higher gears..

sorry I'm not trying to hijack but I'm curious too as in the long term affect of running a larger set of shoes with stock gears.

 

VIN will not tell you your gears but, your axle code will...sticker located in the drivers door jam.

 

Programmer would definitely help by getting shift points and mph back where they should be. Also improve performance. Also like tech rep says check the door jam for the sticker with axle code and do a quick google search for a chart. I don't think I have seen many fx4 with 3.55 but I'm sure there are some out there but with that being said I would be willing to bet you have 3.73

 

H6 is 3.55 and B6 is 3.73 on the axle code section of doorjamb. Like previous reply said, nearly all fx4s are 3.73. Krb, with the 35s, depending on if u do a lot of city or highway driving, a gear change to 4.10 or 4.56 would help your power and mileage significantly. 4.56 is usually recommended with 35s, unless you do a lot of highway driving, then 4.10s may be better.