• When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.

8 3/4 parts interchangeability

old guys rule

FBBO Gold Member
FBBO Gold Member
Local time
3:00 AM
Joined
Sep 14, 2016
Messages
1,322
Reaction score
445
Location
Jacksonville, FL
I have two 8 3/4 centers...a 742 & a 489. The 742 has a reman cone sure grip, therefore, I believe both the cone and diff case have been machined and a spacer inserted. Can this sure grip now be used in the 489 diff?
 
Yes, but nothing else will swap over.
 
The crush sleeve eliminator? I would, drop that crush sleeve like a bad habit.
 
Factory spacers are mostly all the same. Carrier bearings inner race i.d. is the same. So yes, Sure Grips can be swapped between carriers.
 
The cone-type and the clutch-type SG's use a different bearing and race but the carrier/bearing/race assembly is interchangeable in any 8 3/4".
 
The crush sleeve eliminator? I would, drop that crush sleeve like a bad habit.
not the crush sleeve. the sg had to be resurfaced, so a spacer was needed to take up the amount that the resurfacing removed
 
Just a side note here FWIW.
This pinion ran in a 489 case that I disassembled. Notice, that is a crush sleeve/washer/spacer on the pinion spline. It ran against the shoulder to the right. So it's seems possible to use a "large" stem in the 489 case. I doubt a "tapered" pinion fitting in a 742 case....……..

Gear1.jpg


Gear.jpg
 
Last edited:
The 489 is the large stem. And I’m not seeing any crush washer.
 
Huge difference there between the 2. And that pinion with all the other parts is a 742.
 
That pinion doesn’t look to have a taper.
 
Somebody frankensteined that 489 case with a 742 pinion in it.

For the OP, yes the suregrips can go into any case. Take the SG case, bearings and races from one case to the other.

Ring gears are all the same across all cases as well. But don't mix and match them after they've been run with a pinion. Wear pattern difference will create a bunch of noise/whine in almost every situation.
 
Hey fellas. Very interesting! Keep talking about the differences. But I did just go out to the shop to take a peek at the pinion that I took out of a 67 Charger. It had a 742 case with a clutch style sure grip. Which I plan to put in my 489 case in my 70 Charger. The pinion was a large one like in the picture up above. But I took the pinion out of the 742 case. The pinion in my 70 Charger is a tapered one in a 489 case. Not like the one up above.
So there must be a way with bearings and the races that the large stem pinion will work in a 489.
Anybody confirm that??
 
Knock out the races and compare the numbers, something is really odd here!
 
Holy hell! I've opened a can of worms here without even meaning to. What I was actually talking about was (I believe) the cone (or cones) had been machined (and/or) the SG case making it necessary to use a spacer to allow for the amount of material machined away and if that made a difference when transferring the SG from a 742 pig to a 489.
 
Holy hell! I've opened a can of worms here without even meaning to. What I was actually talking about was (I believe) the cone (or cones) had been machined (and/or) the SG case making it necessary to use a spacer to allow for the amount of material machined away and if that made a difference when transferring the SG from a 742 pig to a 489.

Lol, and I thought the threads about "8 3/4 parts interchangeability"! :)

I would think you should be good to go if this is what was done to the cone sets....….
https://www.forabodiesonly.com/mopar/ams/how-to-recondition-a-sure-grip-cone.28/
BTW, make sure to test fit the axles before you install.

Knock out the races and compare the numbers, something is really odd here!
See post #8, top picture. What you see there is in fact what came out of it with 513 gearset. I already have another R&P in the case...…. a tapered set with CS eliminator from Cass.

...….Anybody confirm that??


I don't believe the 489 case had been machined at all. That's why I posed the question to Crackedback.
I'll see if I can find a better picture of the bearing-race combination that was used for it and post.
 
Auto Transport Service
Back
Top