489 Crush sleeve or Eliminator

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Mojoe9955

Mojoe9955

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I just repaired/setup a 741 center section. Turns out the pinion didn't have enough shims to achieve the correct backlash. I got a Doc Diff installation kit, hogged out the old bearings to make it easy to facilitate adding/subtracting shims. It took about 6 or 7 times to get it right. It's back in the car and all is good.
I'm about to switch from 4:10 to 3:23 gears in a 489 I have. It looks to me if you use the crush sleeve eliminator it gets set up using shims like a 741 and 742, which I found to be a pain in the a$$ and don't see the advantage as the crush sleeve seems to me other to be the easiest way to go. Pro and cons please?
Thanks
 
Mojoe9955 said:
I just repaired/setup a 741 center section. Turns out the pinion didn't have enough shims to achieve the correct backlash. I got a Doc Diff installation kit, hogged out the old bearings to make it easy to facilitate adding/subtracting shims. It took about 6 or 7 times to get it right. It's back in the car and all is good.
I'm about to switch from 4:10 to 3:23 gears in a 489 I have. It looks to me if you use the crush sleeve eliminator it gets set up like a 742, which I found to be a pain in the a$$ and don't see the advantage as the crush sleeve seems to me other to be the easiest way to go. Pro and cons please?
Thanks
Click to expand...
They take a LOT of torque to crush and I mean a LOT. More than an impact gun, so if you don't have a way to do that, I would recommend an eliminator. I recommend it anyway, because it makes the rear end a little stronger.
 
RustyRatRod said:
They take a LOT of torque to crush and I mean a LOT. More than an impact gun, so if you don't have a way to do that, I would recommend an eliminator. I recommend it anyway, because it makes the rear end a little stronger.
Click to expand...
I definitely was thinking about how to go about the crushing part.
 
I put my used crush sleeve in a 6 ton press and it didn't do a damn thing to it.
One guy on Youtube said you can re-crush them in a vice "to get the crush started"
I'd like to see this vice
 
65TerrorCuda said:
I put my used crush sleeve in a 6 ton press and it didn't do a damn thing to it.
One guy on Youtube said you can re-crush them in a vice "to get the crush started"
I'd like to see this vice
Click to expand...
Me and you both!
 
I have never built an 8 3/4, but have done many GM 7.5 and 8.5,8.6 and have always used 1/2 impact to crush. Once you get the crush started it becomes easier, but you have to be ready to stop, know how to feel the pinion tightness, too much and you start over. I think the torque was 30inch lbs on new pinion bearings, 15inch on old. But the 8 3/4 crush sleeve is really beefy !!! No wonder guys are using eliminators.
 
Inertia said:
8.75" Rear End Torque Specs

All specs are lbs-ft, unless noted

Bearing Cap Bolts 90
Ring Gear Bolts 55

Pinion Flange Nut:. Min torque
Small Pinion. 741 120

Tapered Pinion. 742. 170

Large.Pinion. 489. 240

Click to expand...
Yeah, but that ain't the same as what it takes to crush the crush sleeve. Not by a long shot.
 
Crush sleeve doesn't know or care if it was pre-crushed.
Couldn't get crush sleeve for a while back 1970's, my mentor went next door to the machine shop and had about 100 - 10 thou thick shims made.
We have never bought a sleeve since, - just add a shim and crush the sleeve a bit more.
We were doing a diff a week for a long time .
 
Inertia said:
Crush sleeve doesn't know or care if it was pre-crushed.
Couldn't get crush sleeve for a while back 1970's, my mentor went next door to the machine shop and had about 100 - 10 thou thick shims made.
We have never bought a sleeve since, - just add a shim and crush the sleeve a bit more.
We were doing a diff a week for a long time .
Click to expand...
I've reused so many crush sleeves and just tightened it down "a little more" that I've lost count. Never had a problem. But sho nuff as I recommend it to someone, their chit will tear all to heck and back.
 
Inertia said:
You may be thinking GM RRR,
They were 210 ish IIRC.
Click to expand...
Maybe, I don't know. I DO remember getting on a 3/4 drive ratchet with a 5 foot long pipe to do one one time. We got it done, but it took three of us. Two on the ratchet and one holding the brake HARD because the parking brake would not hold it.
 
The 30inch and 15inch lbs is the rotating torque of the pinion gear via the nut only after you crush it. Yeah it takes a ton of torque on that nut to crush the sleeve.
 
I'm probably going to get new stuffs for my 489 as I don't know the condition of it. I made the mistake of putting the swap meet 741 that "worked good when he took it out". I put it in and it definitely did not "work good". Lesson learned, but I have a hard head.
Asking for a friend...is it feasible to change the ring and pinion using the old parts including old crush sleeve?
I would put the marking compound and check the condition before hand.
 
The last crush sleeve I tried to use was for a customer and his 489 housing. He provided all the parts to install a 4.10 gear set. I tried to set the pinion bearing preload, had the pinion nut torqued to over 450 ft. lbs. and still had free play. Ended up pulling the threads out of the pinion nut. So I purchased a solid spacer with shims and set up the rear. I have made my own solid spacers for other rears I have set up, and never had any issues
 
1969 Factory Service Manual diff torques .


IMG_20240625_084357_419.jpg


IMG_20240625_084339_750.jpg
 
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