What would you do with a 8 3/4 489 that was given to you?

What would you do with this center section?

  • Completely rebuild it - don't reuse any parts and go with new 3.55 gears

    Votes: 33 38.4%

  • Replace the worn limited slip with the Truetrac and replace the pinion seal

    Votes: 46 53.5%

  • rebuild the existing limited slip and just keep an eye on the pinion seal

    Votes: 7 8.1%
  • Total voters
    86
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Weak440

Weak440

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I have a 489 center section with a bad limited slip (worn out) and a bad pinion seal (was told it leaks like crazy). But, the bearings and 3.23 gears are supposed to be good (used obviously).

I was thinking of replacing the limited slip unit with a Detroit Truetrac Differential and replacing the pinion seal. I am going to have to change from the 7260 yoke to the 7290 that I use any way.

I really want to keep the 3.23 gears - What would you guys do?
 
I took the middle vote, but honestly my decision would depend on the motor/trans that was pushing this. Also what I was using the car for (drag, cruise, or daily)
 
Give it to someone else :happy1: I went with the middle
 
It is eventually going to go in a '74 Duster with a mild 440/727 that is mostly going to be street driven and occasionally driven to the track.

The 489 has a crush sleeve in it doesn't it? I have a feeling that pulling the yoke is going to cause me problems with it?
 
personally i'd pull the guts keep the case & start over new why would you want to deal with 30+ year old parts including the gears that you know nothing about especially when you have a nice reliable street driver car???
 
Take it apart, clean and paint the casting, inspect the gears for wear, inspect the bearings for wear, install a solid pinion spacer, replace the sure-grip with a power lock unit with new side carrier bearings and that 440 with the right convertor will love it.
 
I second 69MOPE, the power lock unit it so much more reliable and will hold up better. Pull apart and check old parts and re-use the bearings if good, but you'll need the conversion bearings for the end caps to go with a power lock posi in the 489 case. Mancini carries all of this.
 
a1972dartswinge said:
i second 69mope, the power lock unit it so much more reliable and will hold up better. Pull apart and check old parts and re-use the bearings if good, but you'll need the conversion bearings for the end caps to go with a power lock posi in the 489 case. Mancini carries all of this.
Click to expand...

x3
 
If you decide to replace the original SG, I would be interested in buying the old one. I vote on the middle one too.
 
Thanks for the help guys! I am going to start collecting parts and tare in to this project in a couple weeks. I will keep you guys posted because I am going to be asking lots of questions!

Thanks again!
 
Sorry that I don't remember who, but someone posted a while ago that they would machine the end of the cone so it could move enough to work. I think that it would be OK for a mostly street car.
 
Hmmm... That sounds familiar - I may have to look in to that. Thanks!
 
Ted Carlson said:
Sorry that I don't remember who, but someone posted a while ago that they would machine the end of the cone so it could move enough to work. I think that it would be OK for a mostly street car.
Click to expand...

X2 you just need to fresh up the clearences in the cone sure grip.
Take about .030 off the cones and put a .030 shim behind them.
Any Ma / Pa machine shop with a manual bridgeport can do this for less than a $100.00.

I am getting ready to do the same thing with my used $60 2.76 489 case open.
Converting to cone sure grip used $150.00, with a new 4.30 gears and install kit.

I will have about a little over $550.00 in a fresh center doing the work my self, if you have to pay somebody add a couple hundred bucks.
 
Deleted...I didn't help....just said you could give it to me......sorry that's why I deleted it
 
If you get rid of the sure grip Ill buy it off you. But you should just pull it apart and replace the bearings pinion seal and rebuild the sure grip.
 
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