So I'm totally new to gear swapping and differential. I currently have a stock 1996 f150 302 with 8.8 gears with 3.55 LS. I want to put 35" tires on it and was wondering could I use the stock gears or what would be the best setup for the rear and/or front differential? I do know that a gear swap would put less strain on the truck with bigger tires and I dont want to be putting too much strain on it. I wont be hauling anything serious and will be mainly used for a daily driver. I wont be doing any serious off road either. Any information on the best setup is appreciated

 

Assuming you have an E4OD trans, then 35" tires and a 3.55 rear end will put you at about 1450 rpm at 60 mph. You won't be able to pull that very well with a 302, so you'll be shifting out of overdrive a lot. Assuming you have 235/75-15 tires now (29" tall), you're turning about 1750 rpm at 60. To get back to that with the 35s you'll need to change to about 4.28 gears (3.55 * 35 / 29 = 4.28).

If you want about the same performance you currently have, then somewhere around 4.28 (or possibly even a little deeper, like 4.56) would be a good bet.

I'll assume that gas mileage isn't a big concern for you. If it was you wouldn't be putting 35s on it. But if you don't want to lose quite as much mileage, then you might want to go a little taller, like around 4.10. That'd put you a little below 1700 rpm at 60. Still kind of low for a 302, but if you aren't hauling anything it'll at least be possible to use overdrive there.

Oh, and if my assumption about your trans and current tire size is off it will change the numbers a little.

By the way, my Bronco has 33" tires, a NV3550 trans and 4.10s. Neither my overdrive nor my tires are quite as tall as what you have, so my 4.10 gears are effectively the same as 4.77 gears in your truck. Personally I'd like a little taller than that, but they are tolerable.

 

I do appreciate the info. And the assumption is right. I do have the E4OD tranny and I'm running 235/75/15 right now. It was common sense that I would lose gas mileage so I was expecting that lol anyways back to the gear swap, the 4.10 gears would give me the better gas mileage? If possible I would like to keep the same gas mileage I have now which is around 13-14 mpg. And do you know any good places to get the gears from?

 

I'd count on getting worse mileage with 35" tires no matter what gears you run. You might get a little better with 4.10s than with 4.56s, but that'll depend on how hard you drive it. When you push it a little it'll downshift more often with 4.10s than with 4.56s and 4.10 in drive will be worse than 4.56 in OD for mileage.

And sorry, no, I don't have any gear supplier to recommend. There are a lot of them out there and I think most of them are good.

I will say that unless you plan on doing the gear swap yourself it's probably better form to let the shop that does the swap source the gears as well. And if you do plan on doing the hears yourself, make sure you know what you're doing. Setting up gears isn't brain surgery, but it's sort of one of those "if you have to ask, you probably can't" things.

 

Last couple I did I used Motive gear and had good luck.

4.30 gears would be technically correct, but the 35's are heavier. I'd lean in the direction of 4.56 gears. 4.10 are good for 33's but may be a little weak with 35's.

 

Here's a web site that lets you put in the infromation you have and the infromation for what you want on the other side and if you scroll all the way to the bottom it'll tell you the difference in RPM/speed between the two.

 

I'd vote 4.56:1 for 35's and a 302 rather than 4.10:1. The 302 needs to wind out a bit more than a 351 or big block, so gear it to do so. Not my words, but "never fear the gear".

 

35s and no serious off roading...? ...


With 36" tires, I went with 4.56 gears and am happy with the decision. Good enough for slow crawling off road which you probably won't ever have to worry about, and high enough to still drive on the highway and not hate life.

 

With a 5.0 get 4.56 gears and don't give it another thought.

 

Thanks guys for all the help. I think im gonna go with the 4.56 gears in the back. Now I do have a 4x4 and I was doing some research that said I would also have to swap the gears in the front. How can I tell what kind of front axle I have?

 

Your truck has a Dana 44 TTB front axle and you will need the matching 4.55 gears for it.

 

Just an FYI, regearing will cost around $600 per axle to have a shop do it. That's in my area anyways.

 

+1 for the 4:56 gears. I had a 90 Bronco with a 351,E4OD and 3:55's. I bought it that way and it was a total dog. Had I kept it I was hoping with the 4:56's. The little bit of extra gear helps with the added weight and rolling resistance of the bigger tires.