Hello,
I know this has probably been asked many times, and I tried searching on 3.55 3.73 and then 3.55, and then 3.73 alone, but nothing came up.

So can anyone tell me the pro's/con's of 3.55 vs 3.73 LS on an FX4? 3.55 is standard with 20" wheels, and 3.73 is optional with 20" wheels.

Thanks,
JSB

 

3.73's will give you more torque at any speed, thereby making a faster acceleration and will also allow you to pull/tow more easily, but 3.55 give you a better hwy milage.
If it were me I'd go with the 3.73 that's not a very drastic change in gear ratio, especially with 20's, they're usually kinda heavy to turn. There are I'm sure more pros and cons

 

My 05 has the 3.73 LS. At 70 my RPMs are at 2k even. With the 3.55 you might cruise at 1800. I like the 3.73 more for the better launch off the line, better (easier) pulling, etc.

 

I have an XLT with 3.55's and 18" wheels. I'd rather have the 3.73's for better acceleration in town. 3.55's and 20" wheels will be even worse.

Grim

 

Not a heck of a lot of difference between these. Now, if you were comparing the 3.55 with the 4.10, we would be talking some difference.

I got the 3.73 LS just because I tow stuff. I don't think think I am taking much (if any) loss in mpg when I am not towing. I do a lot of highway driving and at 55 mph the tac is dead on at 1500 rpm. Hit the cruise and it stays dead on at 1500 for just about any grade it goes up. Not bad considering the Ranger I used to drive was at 2000 same speed.

 

I've always had the 3.73 gears in my trucks. But like everyone has been saying, there really isn't a lot of difference between the 3.55 and 3.73. If you plan to tow or haul anything, I'd go for the 3.73.