good way to put it.

 

not trying to argue, but. well if your going up a hill, I would understand the need of numerically higher gears there, because you want lower end gears on any type of well, "obstacle" i guess you could say, just like mud or rocks. But on the highway, usually your vehicle is already up to speed and is cruising. So like on a bike.. once your already up to speed on flat ground you dont want to be pedaling fast still..you want to pedal slow and just keep up what you have going. right? or did i just get your whole explanation bass ackwards? :o

 

honesty, i am probably going to go w/ the 4.56's. anyone have any suggestions on upgrading from the stock LS? I want something that is road friendly as well.

efuehrin: i will be contacting you, don't worry.

Cecil: whoever told you 4.88's won't work is BSing you. the only "obstacle" i can think of is the 8.8, however, they make many ratios for the 8.8 rear as well. i still STRONGLY believe you should swap to the 9.75 before opening your pockets on regearing b/c of your plans for the truck buildup. a salvage axle would be cheap, and you could always drop that off to get regeared, along w/ the front differential. that way you're not out of a truck.

a brief OT question: why is it that they don't make the 4.30 in an 8.8 reverse cut for the front? anyone have the slightest idea?

cotedog03: correct, hence my "worry" about killing my top end, highway performance by going too low.

 

just outta curiosity when I replace my rear differential to a 9.75 do I need to replace my front Differential

 

No, they can be any size. The 5.4s have 9.75s in the rear and 8.8s in the front.

The just have to be the same ratio.

Just and idea guy's. If you aren't sure about your ratio choice, just do what I did and only do the rear. Then disable your 4x4. (I put a big X across my switch with red electrical tape.)

Then if you don't like the ratio you only have to buy one new set of gears instead of 2 sets.

 

ehuehrin

is the 12.5mpg city or highway? Just wondering bc I am pretty sure I will be going with the 4.56's myself shortly and am wondering what kinda drop I am going to be seeing. Not to concerned either way just would like to know out of curiosity. Thanks

 

12.5 was about 90% highway. 70mph

I'll admit I was taking it easy during that tank, but I average 11-12 on everyday normal driving.

I have gotten as low as 9.7 but I was pulling a enclosed trailer for about 140 miles on that tank.

 

all right thats what I was looking for thanks, one last thing do you think there will be much difference between your 5.4l 2v and my 5.4l 3v?

 

No clue. I don't know anything about the new engines. My guess is that you may get a little better MPG.

FYI I took this last night with my phone on the way home last night. Remember I have 35's and 4:88s

 

Thanks, I am guessing there would not be much difference at all. And I wouldn't be going with 4.88's only 4.56's. I am onlu going to go 6" with 35-36" tires tops nothing to crazy. But who knows maybe I will go with the bigger gears. Either way that pic was pretty cool and thanks for all the info you have posed in this thread helped me out a ton.

 

No problem, By the way I have some pics in my gallery from when i did the rear end if your thinking of doing it yourself.

 

How hard is it? I might just have to do that I am going to check your gallery now.

 

It wasn't too hard. You have to get the pinion bearing pressed off the old and a new one onto the new pinion.

I used all my old spacers and shims and everything was fine. If for some reason it's off with the old shims it could get a little more tricky getting it set up correct i guess.

Hardest thing for me was to get the cover to quit leaking. I ended up buying a new one. Ill be around if you want some help.

 

Well I might just have to try it. But first things first I have to purchase them. Any recomended sellers or manufactures of these gears.

 

www.accuautoparts.com

They had the best prices I could find. I got the Ford Racing 4:56 gears form summitracing. I was told to get ford racing or Yukon. Try not to go too cheap.

Like I said previously I have some Ford Racing 4:56's collecting dust in the garage if your interested. PM me if so and I can give u details.