2001 supercrew 6 inch fabtech and 3 inch PA with 35 inch tires, ive got stock 3.73 gears and cannot stand how slow it is up in the mountains towing a small trailer with one atv, ive thought about going with 37s but im not sure at the time anyways with 35s would 4.88 gears be to deep or not, how badly would my 13mpg suffer? anybody with the same setup? how do you like it?

 

I don't keep up with my mileage, im afraid to. Plus i drive aggresive. It'll break them loose pretty easily so just be aware it's alot of gear. You won't have much on the top end but its pretty descent up to around 65 or so.. i have a non pi 4six and assuming you have a pi 5four you might not want lower than 4.56. Hopet that helps some.

If i were you, with the six inch lift i'd def do 4.88's and just upgrade to 37's when you wear out the 35's..

 

You lift a truck and put huge tires on it and you are worried about GAS MILEAGE?????? I think you are lucky to be getting 13!

 

honestly the gas mileage doest really bother me all that much because we do have a accord that gets 38 hwy and a bike that gets 65, i would just like to have an idea of how far its gunna drop for thoes long trips from kansas to colorado and indiana and such.

 

Idk my mileage is s***

 

I agree, if your considering 37's I'd go with the 4.88.

 

the normal speed for me is 75-80, have yall done this with the 4.88s and 35s if so what were your rpms like

 

I ran 4.88's with 35's for about 5 months and it rocked around town, but sucked on the highway. If you roll at 80 mph alot, you'll want to go to 37"s with a set of 4.88's. If your stuck on 35"s, then go with a 4.56.

If I was you, I'd try and do the gears and tires at the same time.

 

I would go with 4.56 for 35s leave the 4.88s for 37s...

 

75-85
2800-3100 rpm's in od
4000-4100 in 3rd

 

the only thing stopping me from going to a 37 or 38 is wear and tear, you guys who have the 37s and 38s have you had many problems with wheel bearings, cv joints, ect.? thanks for all of the help so far!

 

I have an 2003 lariat with a 5.4 in it I'm running 38s with 4.56 gears and have plenty of power with 12 mpg But I do have a cold air intake and throttle body spacer

 

For anyone that finds this thread, I have 4.88s on my 06 5.4 with 35s and I'm churning right at 2k RPM at 60 MPH. Pretty crappy . . . but, they're gonna be awesome in town once they're broken in. I feel like I'll want 37s in the future, so I went with 4.88s, and driving slowly on the highway doesn't bother that much cause I was doing that before.