489 case 3:23 sure grip ???

[Highbanked Hauler]

   I have been considering this rear( out of the parts car) for my 68 BUT  it has a howl  when under load but nothing under deceleration and it has  a lot of free play.  I don't know if the sure grip holds or not, Is there any fix for this or is it overhaul time?

[Challenger340]

Howling "under load", is indicative of a front Pinion Brg because the Pinion is pulled "into mesh".
Pretty common after a Pinion Seal replacement, and lack of correct Torque/Crush applied upon re-assembly.

At the very least, dis-assembly and Inspection should be undertaken, then, if looks OK, a new crush Sleeve/Brg could be applied for re-assembly and correct Pinion Brg preload applied.

[Highbanked Hauler]

  So at bare minimum a pinion bearing and crush sleeve will be needed?  If there is a  wear pattern on the teeth will that cause a howl or not?  I don't have it opened  yet..  In setting a crush sleeve to spec. is this done with an inch pound wrench?   thanks!!!

[Challenger340]

  So at bare minimum a pinion bearing and crush sleeve will be needed?  If there is a  wear pattern on the teeth will that cause a howl or not?  I don't have it opened  yet..  In setting a crush sleeve to spec. is this done with an inch pound wrench?   thanks!!!

You will a big ratchet on the Yoke Nut to crush the sleeve, and something to hold the yoke from turning against the Torque you are applying(Substantial), as you pull the yoke in, crushing the sleeve.

You can use an Inch/Lb Torque Wrench to measure the "Rotating Torque" required to spin the Pinion assembly once the crush sleeve is crushed,
although,
Most diffy Guys, stop periodically as they tighten, then just do it by "feel of hand" as they spin the Pinion.

Too tight, and you'll almost feel every brg roller as you turn the pinion,
too loose, and the Pinion will still have endplay in & out.

If you've never done it before, might be best to have someone there who has, to help out and coach ?

[Chatt69chgr]

Another alternative is to dispense with the crush sleeve and use spacers.  RATECH makes a kit that has the piece that replaces the crush sleeve and an assortment of spacers.  You would use red loctite on the pinion nut.

Since the chunk is so easy to pull, it might be good this first time to pull it, stick it in a 5 gallon plastic bucket and take it to somebody that works on these and will let you watch and learn.  Then you would be up to speed on these units.

There is a real good writeup on the 8-3/4 rear end on the Moparts website.  Used to be good info on the Auto Hobby website but for some reason, it's blocked now.