Considering axle swap from 3.55 open to 3.73 LS

[Jim Jermain]

I have a '00 XLS with 2WD. I live in WI and am considering a switch from an open 3.55 to a 3.73 Limited Slip for better traction and acceleration. Based on great response I got from a previous post, I think I can use a '95 - '01 axle. However I will need to reprogram the computer. As anyone done the axle swap? Do you notice much acceleration improvement going from the 3.55 to 3.73? I have the 4.0 OHV and it tends to be a dog off the line. Also can the dealer reprogram the computer and any idea on the cost? I can get a low mileage 3.73 LS axle for about $150 from some local junk yards so the swap cost isn't bad.

Thanks,

Jim

 

[rileyrs]

if you do any offroading, the limited slip will be an improvement.
you will feel a small improvement in acceleration i bet, heres a chart:
http://www.sierrabronco.com/TireGearRatio.htm

 

[storlied]

Like mentioned above, the LS will be a lot better than open in low traction situations but the acceleration increase won't be huge... I suggest 4.10's for good general performance with stock size tires.

 

[Jim Jermain]

Thanks guys, I appreciate the quick responses.

Jim

 

[Carguy3J]

Like mentioned above, the LS will be a lot better than open in low traction situations but the acceleration increase won't be huge... I suggest 4.10's for good general performance with stock size tires.

4.10's will kill your fuel mileage, if you do any regular highway driving.

 

[storlied]

Acceleration would actually be noticeable with the 4.10's too. But yes, fuel mileage will go down a lil bit. Where as now you're slow off the line but the high end is better and mileage is up. From what I read, most people don't notice any good increase in acceleration by going one step.. but instead two. I'm gonna skip the 4.10 step here and go to 4.56. (I have 3.73ls) Depends on what kinda driving you do.

 

[corkey]

3:73 with a stock tire should be good, it even works up to a 31 inch tire, i know, i ran that for quite a while, i got real good gas mileage with that combination,
as for 4:10's, i am now running a 33 inch tire and that gear works great for 33's on the highway, that's what i have now,

just remember if you are changing the back gears on a 4wd you have to change the front diff gears too , to the same ratio,