Hello everyone,

I went by my local dealer today and inquired about the rear axle in my truck.

Turns out I have the 3.08.

I am running 35x12.50R15's and seem to have a lack of power and no top end on the hwy. Part of the problem is that I need a new distributor but I wanted to see if maybe I should be looking into a new rear end setup. I'd like to go with a posi as i do some trail driving and mudding but it is also my daily driver.

I'd like to hear your recommendations.

Thanks!

 

with 35's Id say a minimum of 4.10 gears.

 

Would you mind educating me on gear ratio's, It is something that I haven't gotten into yet.

 

I'll give it a shot, but no promises you will understand lol.

If you open the cover on the back of your rear you will see 2 types of gears, a ring gear (attached to drive shaft) and pinion (attached to axles). Basically if you take the number of teeth on the ring gear and divide it by the number of teeth on the pinion gear you have your gear ratio.

Example: your ring gear has 37 teeth and your pinion gear has 9 teeth, you have a 4.11:1 gear. What does that mean? Glad you asked.

Simply put it means that every time the Ring gear makes one complete turn, the pinion will turn 4.11 times.

Now it's not hard to figure out that a 4.11:1 will translate into being able to accelerate faster than say a 3.08:1 gear, BUT the 3.08:1 will have more top end or top speed than the 4.11:1. Now throw in tires sizes.

Your 3.08:1 gears turned your stock 27 inch tires just fine, but you increase the tire size to 35, now your 3.08:1's struggle to spin the larger tires, this hurts everything before your rear (trans etc) as they must work twice as hard to be able to turn those tires. Changing to a lower gear ratio like 4.10:1 will make those larger tires easier to spin for your drive train and give you seemingly much more starting power, much like when stock tires were on it with your 3.08's.

Basically it will balance out the power needed to turn the larger tires with out putting a massive strain on your drive train.

It's more difficult to explain that I thought it would be lol. I'ts kind of one of those things you either "get" or you don't lol.

 

That makes complete sense, So i want a higher ratio for my application.

How would I go about getting a posi, is that a complete axle replacement?

 

not necessarily, unless your axles are worn. But it's not as simple as buying your gears and just bolting them in. Unless you have a pretty well stocked shop with a press and various other tools, your going to want to have the gears installed for you by a qualified mechanic with the right tools to do it with. It isn't cheap the gears alone new will be around $300.00 or more (approx) unless you can find a rear already geared where you need it, then if you have 4X4, you will need to do front gearing as well. (they HAVE to match in a 4X4).

I haven't looked around this site yet, but I would bet there is a "how to" on changing gears and equipment needed.

 

like he said, 4.10 minimum, id prob get 4.56s and i know someone on here payed like 1500 bucks for a shop to install new gears, thats parts and labor, and he is 4wd. you can do it yourself, but i wouldn't unless you are a pretty good mechanic. i believe a locker or limited slip is like 300-800 bucks usually.

anyone please correct me if im wrong on the prices.

also like he said, it would be easier to find a whole axle and put it in, thats something most mechanics can do, but with that comes the possibility the axle is warn out and a whole bunch of other things. you can usually get a complete rear end for around 250-500 bucks, used ofcourse.

 

This right here is a handy chart bigred posted on another thread. http://auto.howstuffworks.com/auto-p...size-chart.htm
Hopefully that'll help decide the gearing that's most practical for you. As far as prices go I'm about as useless as the "ay" in okay

 

lol yea iv seen that chart before, im dieing to see what my truck with stock 28s or 29s would do with 4.56 gears lol. when i upgrade the 32s the gears would be perfect if i wanted to tow also, great to know.

 

I thought it was a good reference. I wanna throw the 4.88 in right now with my 31s xD
Talk about a jumpy take off. It'd almost be hard to drive.