3.55 gear install.....possible install

[shelbie67]

I have 40,000 miles on my car equipped with the 3.31 gears. I was thinking about buying 3.55 gears for just a little difference while still maintaining decent highway mileage. I have been told that i can just do a simple gear swap with fluid. Is this true?

 

[shelbie67]

btw.....i have always changed my diff fluid @15,000 mile intervals.

 

[JeremyH]

btw.....i have always changed my diff fluid @15,000 mile intervals.

Why? Gear fluid is jsut getting broken in and good at that many miles.

You really only change gear fluid when you have to as you broke open the diff to do work. The fluid will easily last 50-75k miles.


What do you mean simple gear swap with fluid? At 40,000 miles its good idea to get a new bearing kit really nothing to do with the fluid you could resuse that fluid if you wanted.

 

[gmantheman]

Do you mean that the only thing you will need is the gears and fluid? I would be safe and buy an install kit and new bearing just to be safe. This has been discussed before but going only one gear steeper such as 3.31 to 3.55 is a waste of time and money. Just get 3.73 or 4.10s. Your hwy mileage will not suffer that much. Maybe 1-3 MPG at the most.

 

[shelbie67]

anyone know how much the bearing kit are.

 

[Chris B.]

Like others have said, going from 3.31's to 3.55's isn't worth the cost.

My 2008 GT with 3.55's got 23-26 MPG highway depending on the speed and hills. My 2005 GT with 4.10's gets 21-23 MPG highway depending on the speed and hills. Its not a huge difference in MPG. If you are concerned about gas mileage get 3.73's instead of 4.10's.

 

[bullitt4434]

my bullitt with 3.73s can get 25 easy sometimes a bit more

 

[Chrome61]

I agree with going from 3.31's to 3.55's is a waste of time and money, I went from 3.31's to 4.10's and now back to 3.73's, The 4.10's was a bit much for my driving style after I put the blower on but I don't track the car.

The 3.73's suit my car perfectly, I average 22.7 mpg city/highway.

 

[JeremyH]

Bearing kits is around $100.