Author Topic: Replacing Rear end (Read 1055 times)

Waffles · « **on:** April, 16, 2010, 02:37:18 PM »

Ok guys, I FINALLY got everything for my 9" rear end, I THINK.

Housing, 28 spline 3rd member, 3.50 posi, my 8" axles to match the 28 spline 3rd member, friction modifier, gear oil, a new gasket etc.

The 3rd member is already set up. I have to pull the 8" from my car, pull the axles out, put them into the 9", and the pig in the housing, put it into my car.

Can anyone walk me through this? Would like to do it this weekend. Just have never done it before, and don't want to make a stupid mistake that will cost me big bucks.

So I'm looking for some step by step instructions on what to do, things to make sure I do and don't do, it. Was told to mark the driveshaft before I remove it? I dunno.

Thanks for the help fellas.

Waffles · « **Reply #1 on:** April, 16, 2010, 02:38:36 PM »

Sorry missed the thread a few down... will read it first.

Midlife · « **Reply #2 on:** April, 16, 2010, 03:11:30 PM »

Welcome back! Where the ehll have you been?

silverblueBP · « **Reply #3 on:** April, 16, 2010, 03:54:59 PM »

:wstup

You even missed us wishing you a happy birthday

AtlantaSteve · « **Reply #4 on:** April, 16, 2010, 05:42:58 PM »

What gear did you have in your 8"??

johnpro · « **Reply #5 on:** April, 17, 2010, 03:24:51 AM »

It's a very straight forward process. Remove everything from the 8" axle, and remove the axle.

It is not necessary to mark the drive shaft ... it's balanced. It can hook up any way you want and it will still be balanced.

Put the chunk in the 9" housing, bolt on what you can and put it back in. Put the brake backing plates and axles in after the housing is in. Then just fill it with gear oil (don't forget the friction modifier) and go do some figure 8's to seat the clutches.

There really isn't much you can screw up here.

Waffles · « **Reply #6 on:** April, 17, 2010, 05:30:41 AM »

Thanks for the birthday wishes!! They had the site blocked at work, and I work 70 hours a week, so it wasn't on the biggest list of my things to do when I got home.

I unblocked it myself, so I'm going to try to be on more.

Stupid question, where do I put the gear oil in?

Also, do I need new axle seals? Here's what I have, tell me if I'm missing anything;

Housing
3rd member
My existing axles
Gear oil
Friction modifier
3rd member gasket
existing brake stuff from my 8"

To answer another question, my 8" is a 2.75 open. Should be night and day going from that to my 3.50 posi.

Thanks guys.

silverblueBP · « **Reply #7 on:** April, 17, 2010, 06:59:06 AM »

Since you'll have it apart, new seals and bearings would be a good idea!

cmayna · « **Reply #8 on:** April, 17, 2010, 07:33:48 AM »

Quote from: Waffles on April, 17, 2010, 05:30:41 AM

Thanks for the birthday wishes!! They had the site blocked at work, and I work 70 hours a week, so it wasn't on the biggest list of my things to do when I got home.

I unblocked it myself, so I'm going to try to be on more.

Stupid question, where do I put the gear oil in?

Also, do I need new axle seals? Here's what I have, tell me if I'm missing anything;

Housing
3rd member
My existing axles
Gear oil
Friction modifier
3rd member gasket
existing brake stuff from my 8"

To answer another question, my 8" is a 2.75 open. Should be night and day going from that to my 3.50 posi.

Thanks guys.

Axle seals-Unless you know for a fact that they are new, I'd replace them.

Where to add the oil - On the front of the chunk, driver's side, is there a hex plug? I assume the housing (back of center)doesn't not have a plug on it ?

silverblueBP · « **Reply #9 on:** April, 17, 2010, 07:40:25 AM »

You can always add the gear oil before you install the last axle.

68EFIvert · « **Reply #10 on:** April, 17, 2010, 08:19:20 AM »

My center section did not have the hex plug and I did not notice it until I was ready to fill it with fluid. I had to use the breather port on the top of the ds axle tube. A real pain in the arse. If you don't have a fill plug I would add one to the back of the housing. I also added one to the bottom of the pumpkin for changing fluid later. I welded a 1/2" nut on the bottom and then welded a short piece of tubing around it for protection. I can now use the tubing as a jacking point and don't have to worry about jacking on the drain nut. A simple nut welded on the housing about 3/4 the way up functions as my fill hole.

Waffles · « **Reply #11 on:** April, 17, 2010, 08:30:21 AM »

Quote from: silverblueBP on April, 17, 2010, 07:40:25 AM

You can always add the gear oil before you install the last axle.

So just dump it into the housing if I need to do this?

silverblueBP · « **Reply #12 on:** April, 17, 2010, 08:33:18 AM »

You can pour it into one end of the housing after the other axle is installed. I usually raise one side up so it's easier to pour into.

Waffles · « **Reply #13 on:** April, 17, 2010, 09:33:36 AM »

Thanks for all the advice guys! I'm going to try to knock this thing out tonight and tomorrow.

The housing has all the studs, but no nuts... any idea on what size nuts I need to get for it? And I heard something about copper washers, what's that go on? These nuts or is that something else altogether?

silverblueBP · « **Reply #14 on:** April, 17, 2010, 11:14:00 AM »

Copper washers go under the nuts, which I think are 9/16"....but I'm not sure. Hopefully someone else will chime in.

Waffles · « **Reply #15 on:** May, 02, 2010, 11:55:54 AM »

Ok guys. Did the swap yesterday and today.

I have everything installed, bled the brakes, etc.

Took for a quick drive. Getting kind of a humming when I am driving... like a low, muffled hum i guess.

I added 2 quarts of the gear oil, and one little thing of friction modifier, by dumping it down before installing the last of the two axles.

What do I look into now to figure out the humming?

tarafied1 · « **Reply #16 on:** May, 02, 2010, 04:39:06 PM »

it is a traction-loc diff I presume, is it new or rebuilt? or used?

Sluggo · « **Reply #17 on:** May, 02, 2010, 05:33:44 PM »

Did you break in the trac-loc?

Sounds like maybe your preload is a little loose.

tarafied1 · « **Reply #18 on:** May, 02, 2010, 06:57:42 PM »

Quote from: Sluggo on May, 02, 2010, 05:33:44 PM

Did you break in the trac-loc?

Sounds like maybe your preload is a little loose.

that's kinda what I was thinkin'

johnpro · « **Reply #19 on:** May, 02, 2010, 07:31:17 PM »

Quote from: Waffles on May, 02, 2010, 11:55:54 AM

What do I look into now to figure out the humming?

You basically have 2 choices ... live with it, or pull the chunk and check the backlash with gear marking compound. You may be able to adjust out the hum, maybe not.

Sounds like this was either a used rear, or an improperly adjusted one. The hum is just going to be annoying. It really won't have any impact on the drive-ability, and longevity is probably only slightly diminished.

There's not a thing you can do, though, without pulling the chunk back out.

Waffles · « **Reply #20 on:** May, 03, 2010, 04:47:46 AM »

The chunk was used, but looked super clean.

I kinda figured the same thing, as far as pulling the chunk and having it checked out.

Thanks for the advice, I'll probably do that this week.

AzPete · « **Reply #21 on:** May, 03, 2010, 05:05:29 AM »

Louder pipes or more powerful radio......otherwise pull it. I have been told once they start howling a bit, you may never get them to stop. Has to do with the wear pattern being "set" and not changeable without other noises showing up.

daveSanborn · « **Reply #22 on:** May, 03, 2010, 07:45:14 AM »

Quote

I added 2 quarts of the gear oil, and one little thing of friction modifier....

From my experience a 9" rearend will hold ~2.75 quarts (plus the friction modifier) of oil. Ensure you're oil level isn't part of the problem before pulling the chunk back out.

Waffles · « **Reply #23 on:** May, 03, 2010, 11:40:59 AM »

Not a bad idea. This is just the quantity the guy at NPD said I'd need, I didn't know otherwise.

Problem is, I don't want to dump another qt of it in, then drain it back out if it's not the problem... is it ok to drain it and reuse it if I have to pull the chunk?

Have a friend that rebuilds 9" rear ends all the time coming over tomorrow night to listen to it and tell me what he thinks it is, but I'll spare his time if there's any likelihood of it just being too little gear oil...