Howdy all,

I've been reading this forum for a long time off and on and finally have something to ask. I'm trading my '98 F150 4x4 Regular Cab for a new 4x4 Crew. The old truck has served me well for 9+ years and count 'em 235,000+ miles, and is another example of why Ford builds the best trucks (yep original tranny/engine/etc). Believe me I don't baby my trucks and she still runs good but it's become more and more inconvenient having a regular cab. I'd keep her if I could. Anyway, I'm putting 35-inch tires on the new one and plan on changing the stock 3.73. I believe my choices are 4.10 or 4.56 and I'm leaning to the 4.56's although I really wish I could find 4.30's. I'd appreciate any input from those that have a similar set up as I have about a week to decide. I'm not really a speed freak on the highway as 75 mph would be a fast cruise but I like good response more than anything. Also I pull occasionally and I'm wondering how 4th on 4.56's pulls at 60-65 with say 5-6k? Do you have to go to 3rd a lot? Debating going 4.10 and towing in 3rd if this is the case. The new truck engine is 5.4 as is the old truck. BTW this forum has been hugely helpfull in deciding upgrades, mods, etc.

Mike

 

I'd consider 4.56 or 4.88.
Pulling 6,000 lbs? 4.88 for sure.

I wouldn't consider 4.30s or 4.10 at all. Not with 35s.

A lot of guys run 4.10s with street tires (31 inches or even smaller).
And many of these are guys with blowers, including Lighning owners.

 

I wouldnt even consider 4:10's id go straight to 4:56's. I have 4:56's with 32" tires and still get 16MPG avg. At 60 I am turning 2050 RPM's and if I had 35's that would be lower (Still within the recomended 2000-2500 rpm range) If your going to tow, Go for the 4:56's or lower-you wont be sorry...

 

Don't fear the gear!

 

The 35's will cut the 3.73's down to the 3.40 range, the only thing good is that on the highway it almost act's like a double overdrive. Drop's the rpm's way down, helps mileage but not worth a crap for pullin'! I would try the tires out first and change out the gear's later. Well maybe sooner, before you fry the tranny.

 

i would say 4.10' or 4.56's rather have 4.56's

 

4.56's minimum.

I run 4.10's with a 28" tire and it's perfect.

 

Thanks for the reply's, I'm going to go with the 4.56's. I think this will be the best for the combined driving I do. Can't wait to get this thing.

 

Keep in mind that 4.88 will only be turning about 7% more rpm than 4.56.

So if you are turning 2000rpm with 4.56s, it'd only be turning about 2,140 with 4.88s.

Whichever you choose, you'll love the result.

 

My buddy ran 4.88 on his Chevy with 35" tires. Excellent performance, btw.

 

Sounds like a great gear to choose. Doing the math with the gear calculators online, you are only slightly lower than stock taking into account O.E. tires of 30" diameter (255/70R17). I think an exact would be something in the area of 4.35 which I don't think exists...

While you are having the gears done, SERIOUSLY consider doing limited slips on both ends. WAY better traction control than open. Of course if you have a rear LS, you are halfway there already. The added grip when the roads, or the weather turn nasty is WELL worth the extra scratch, and since you have the diffs out to do gears anyway, might as well do it all the way.

 

Good thinking on the limited slip.

 

i turn 2k at 80 with 35's and 3.73ls