I have a 01 supercrew, with 5.4 v8, 2wd. I currently have 37s on 20 inch wheels. I Drive my truck on the highway at 70 mph everyday for 30 miles. I was wondering which size gears I should put in my rear end. Btw it's a 8.8 rear end. Thanks guys

 

I typed wrong rear end it's the 9.75

 

4:88s

www.accuautoparts.com (I should get a royalty check from these guy's)

yukon are very good, some other guy's may chime in on the brands to avoid, cause there are some brands that people have problems with.

 

Do you not think I will run like 3000+ rpms going 70 mph? I was thinking like 4.10

 

Nope. I turn 2600 rpm at 75mph.

4:88s are definately the way to go.

4:56's if you stay with 35" tires. anything over that you want 4:88s.

I had 4:88s with my 35's for a few years and that worked good too.

 

Are you sure it's a 8.8" rear end? I'm not sure about the 2wd's but the 4x4's have 9.75's if they have the 5.4 motor. The 8.8 is paired with the 4.6l

 

4.88 just seems way to high to me..i am not sure which rear end i have i will have to find out

 

5.4 = 9.75 rearend unless someone swapped it out which would be pretty stupid.

4.2-4.6 = 8.8 rearend unless someone did you a favor and swapped in a 9.75 lol

Now on to your question. If you think 4.88's are too high then go with 4.56's they will work great for 37's as well. DONT DO 4.10's unless you have money to burn. More people than not dont even feel a difference when jumping from 3.55's or 3.73's to 4.10's

 

keep in mind mustang guys use 4.10's on tiny *** street tires. personally, i would go w/ the 4.88's, or even lower, to 5.13's since you have 2WD.

 

488's- no question. I just wrote a novel about this.

 

it is the 9.75 rear end..i got the lift and tires on it and going 75 miles an hour down the highway i run about 2300 rpm.. it seems to me that i dont need gears..

 

flat pavement? have you driven up hills?

If you have taken that thing on hills you will know what I mean. Trans always shifting in/out of overdrive.

How is it around town? Engine revving up to 2k rpms, and shifting, lack of power......

I would get gears. I had a 5.4l, on 35's with 3.73's and it was almost unbearable.

 

mostly flat pavement...all interstate driving..i havent really gotten a chance to drive it around town....it didnt really seem to make much difference in the gas mileage from a 35 inch tire to a 37 inch tire..that was really my main concern there. it would be sweet to be able to burn down a 37 though.. All i do is drive on interstate 10. I live in southeast texas..we dont have many hills here..i have to xcal 2 tuned from troyer.

 

I'd get 4.88

 

Im going to test it and see what the gas mileage is going to be like...if it is a big differen e gears would pay for thereself.