i have a 4.0 with an automatic transmission, and 3.73 rear end, i got bogged down yesterday offroad and noticed that it was hard for me to get my 35" tires to spin, any ideas? it runs great on the road other than my gas mileage.

 

You need 4.88 gears. This question has been asked many times before.

 

does that affect the gas millage any worse than it is now and what about the front?

 

If your truck is 4x4 you have to change the gears in the front too. If it's not then you don't have to worry about it. Gas mileage should improve a little in town, but will probably stay about the same on the highway. The difference in the gas mileage will be negligible, the power difference is what will be noticeable.

 

yea mines a 4x4, how difficult is it to swap the gears? whats involved if you don't mind me asking

 

It's fairly straight forward, but you will need access to special tools like a micrometer, dial indicator, torque wrenches, etc. So most have to take it to a shop. Do a quick search on google and you can find many gear swap how-to's that will give you the general idea.

 

Here's a good how-to for the 8.8: 8.8 Axle Gear Install

 

Oh my god! We are going to set a new record this week. lol

4.88 gears. Need to do front and back. The labor is time consuming and requires some special tools. Generally I recommend taking the truck to someone with a good rep for regearing instead of screwing it up. Labor will cost $1200-1500 most places. Several bearings should be replaced while you're in there too.

 

Is that price per axle Brian?

 

Definitely not, that is for both.

 

I paid $150 per axle where I live. That's just for gear install and bearing setup and stuff... Total when I went to 4.88's and locker I was in it $1,175... That's cuz I had to get a replacement carrier put in the rear.

 

Yeah I found someone here who did mine for $600, but that isn't the norm for most places.

I've heard quotes for over $2000 from lots of places. $1200-1500 is more typical and yes, that's for both axles.

 

Also if you remove the front diff yourself you can usually save a bit of money.

 

im going to ask a stupid question i know but im new to this, does anyone know what the stock differential length is for a 99 ford ranger and whats the 8.8? im just trying to better understand it,

 

http://www.therangerstation.com/tech...plorer8_8.html

 

I always see the same ratios matched up with tire sizes. My question is: Does doing the gear change bring the truck "back to stock" ratio?

I was watching extreme 4x4 this weekend and with their toyota they have 4.88 with 44's. But they also have a 2.1 reduction. According to answers I see on this site, that's way too high

If I wanted to build a trail rig with low gears but I have 35's (maybe 37's) wouldn't I want something lower than 4.88?

This question is more for when I do SAS a couple years from now. It seems when I go back home and say that I would probably put 4.88's with 35's, I get odd looks.

This question may have been addressed in another thread, but if many people don't see this I may just start my own thread

 

Depends on the application, most people don't understand that. I had people think it was weird to use 4.56's with 33's. Anyone who has or knows Ranger's understands why.

 

So, it also has to do with the engine and transmission?

Most likely my 4.0L will stay in my truck (unless it blows or I find a good deal on a 5.0)

 

Everything plays a role and will possibly make a difference. If you leave everything stock besides suspension and tires you will want 4.88's with 35's.

 

Ok, that pretty much answers my question.

But will that make it sorta stock? Should I go lower if it will be a trail rig?

 

yeah you have to remember that full size trucks, which are lifted more often then Rangers, don't need that high of gearing because they put down so much torque to begin with. my buddys 5.7L chevy 1500 has twin 14-bolts with like 3.14s or something and he runs 33s no problem. 4.10s for him would be like us running 5.xx's and 35s.

 

Yes, every vehicle is different. Different gearing in the transmission, different engines that bring the power on and different RPM. My F150 is geared somewhat short with 4.56 gears and 35s, where a Ranger would be geared somewhat high with the same setup.

4.88s and 35s will work great in the 4.0L no matter what you're doing with it. That is slightly lower (shorter) geared than a factory FX4 L2 with 31s and 4.10s for reference. A little lower than stock is better since you're turning a lot more weight/mass, producing more drag, etc.

 

Alright, this is a lot more clear now. I guess my ignorance made me think it was the same for everyone.

Thanks for the insight. Now when I talk to other people, I won't sound like an idiot

 

how do i know whether or not i have the 8.8 under my truck? and im still trying to understand this gear ratio thing im sorry needing guidance so bad right now, but im willing to learn if your willing to be patient with me,

 

There are many ways, but the easiest two are: look at the identification tag on the driver's side door jamb under axle code. Get the two digit axle code and let us know what it is. The other way is to look at the identification tag that is on one of the rear differential cover bolts. Get the information and again let us know.

Another thing to note is that 1990 and up 4.0L Ranger's are always equipped with the 8.8-inch 28-spline rear axle.