I'm thinking of upgrading from 3.23's to 3.73's. Is this something that could be easily done or should I take it to a shop to do. I've swapped rears out in the past no problems but never took one apart. I'm running a 489 case 3.23 suregrip.

Anyone?

It's not terribly hard but you need a few tools. For a one time deal I would take it to a good gear man.

Sheldon

What do you think a fair price is total for parts and labor?

Twenty three minutes is all you can wait for an answer?







I'd suggest you find a service manual, not even necessarily for your car, and read through the procedure. You'll need some special tools, including some big stuff to handle the pinion nut.

You'll need a dial indicator for setting ring backlash

A big puller to get the drive flange off the pinion

A puller/ press to change the bearings on the pinion and possibly the differential case

A torque wrench

If you are going to change the pinion bearing cones, you'll need additional "stuff"

Setting up the pinion bearing preload is no picnic without the proper tools.

Setting up a ring/ pinion is an important step, if you want it to last, and run quiet. I'd find a reputable local shop and pay the sheckles

I'm not sure how you are calculating your time but I appreciate the advice!

I noticed you guys had nothing material to say, either. The point I was trying to make, while making typo errors and still attmpting to remain somewhat light, is that nobody is going to tear into a rear gear for the first time, after seeking advice for an hour or so.

I've done a fair amount of my own work, been into some transmissions and rear ends, and built a number of my own engines, but one thing I would NOT do, is set up my own rear end. I don't have the tools or the experience, and scrubbing the surface off a brand new ring is not my idea of fun.

Just having enough stuff to tighten the pre-load on the pinion nut is no small matter for most backyard mechanics.

It's very easy, but if you have never done it before, have someone show you how or pay someone to do it.

There was an artical in one of the mopar mags not too long ago. They said if you take your time and have the right tools also a manual you'll be surprised how easy it is. I'm still not sure I want to try it.

I do not have all the tools and probably will take it to a shop. I'm still wondering what is a fair price or is it cheaper to find a working center section and swap it out.

this DVD is worth the cost to watch
before tackling the job

http://smartflix.com/store/video/1356/Differential-Rebuilding

If you haven't done one before it would probably be best to have someone that does them do the work for you. Ask if you can watch and help, and ask questions. The next go around you you'll know whats involved and probably be able to dive in yourself. Dave

Here's my

If you can read, comprehend what you read and have the paticence and ability, the procedure in any FSM that covers an 8 3/4 will get you along way. Then you need the tooling, with out it you're pretty much sunk.

I've done 2 for myself with good results, though I'll admit it is some what nerve racking, cuz it isn't something to rush.

Also, on a 489 housing, lose the crush sleeve and go with the spacer and shims from Dr. Diff, 10 times easier for bearing preload.


PM me if you have questions.


Jim Burch

Bare minimum is a dial indicator and a way to measure pinion depth (depth mic). If its an 8 3/4 you need a way to crank on the side adjusters.

I did my first gear swap without a puller & press by cutting the carrier bearings off with a cut off wheel (cut most of the way thru and fracture whats left with a cold chisel) and heating the bearing and freezing the carrier to install them.

If you get the pinion shim kit that has shims that go behind the pinion outer race and the case, you don't need to keep pulling the bearing off the stem. The outer race can be tapped in and out with a brass drift by way of 2 notches in the case.

If this is the only time you are going to do gears, just pay somebody. If you think you will do more in the future, gear up and do it yourself.

My guess is that $100. should cover it if you supply the ring and pinion and the posi centre section. Personally I don't think a jump from 3:23 to 3:73 is worth the money or effort.

Like Stanton suggests
running the 3.73 diff change on one of the free computer simulation programs like CarTest, or one of the relatively cheap programs like Dragstrip Jr or CarTest2000
will show only a modest 0-60 or quartermile change

You could firm this by temporarily fitting some small diameter tires bought used at a salvage yard, or borrowed from a friend.

The computer simulator program Fuel Economy Calculator
from PerformanceTrends will probably show
about a 1 to 2 MPG drop at highway cruise speed
with the 3.73 gearing

It takes some tools. I bought the Mark Williams set up tools for $275, a shop press and some pullers. I may have $600 in tools. I have set up several sets and paid for my tools. I charge $250 to change the gears and all bearings. I take a little more time than a regular shop and try to do a real good job. Have had no complaints so far.