12 bolt carrier questions

[72LB]

I'm getting ready to put this carrier back together but aren't sure on stacking the clutches. The kit has 3 clutches and 4 plates per side but from what I've read a clutch has to go against the back of the gear, is the extra plate not needed? It's alot smaller a stack for the clips without it too. Also the book I have says reuse the shims that were on each side, is that ok or would it be better to use the new shims from the kit?

[Bigdav160]

Reuse the shims and stack two steel plates together in the middle of the pack

[72LB]

Originally Posted by Bigdav160

Reuse the shims and stack two steel plates together in the middle of the pack

So two plates together won't cause any added stress? What about the extra play in the clips?

[randy500]

This is the clutch pack layout.
Eared discs on each side of internal splined clutch discs.
Shims inside of case far away from side gear.

Those carbon fiber disc kits are junk
I would buy an eaton disc and shim kit that is all steel.

You dont just re use shims, you shim each side of the pack to get .001 to .005 clearance between the spider gears (with clutch pack spring preload)

[randy500]

Various posi clutch disc and shim kits have different numbers of plates, the layout is the same, less plates = each plate thicker so the overall pack thickness is about the same.

[68Gold/white]

I hope you kept the outside carrier shims on each side of the carrier together, and marked for each side. The shims are critical for your pinion to ring gear meshing.

[72LB]

Originally Posted by randy500

Those carbon fiber disc kits are junk
I would buy an eaton disc and shim kit that is all steel.

Randy your the first person thats said don't use carbon. I wouldn't be doing this if the carrier wasn't starting to chatter and slip going around corners.

Originally Posted by 68Gold/white

I hope you kept the outside carrier shims on each side of the carrier together, and marked for each side. The shims are critical for your pinion to ring gear meshing.

Yes I made sure of that.

[72LB]

The steel discs looked wore but everything else is ok.

[randy500]

I normally re use the steel discs unless broken or extremely worn and just install new Guides, the half moon pieces, and shim it all up.
You can still buy steel disc and shim kits.

Your discs look fine.
What happens is each disc wears a little then there is lots of play in the spider gears. Use shims to get it in tolerance .001 to .005

The center pin gets worn too where it goes through the carrier.
And the shims under the small gears get worn
The hole for the pin in the carrier gets worn too.
The side of the pin gets worn from the axle shaft.

THe clutch pack total thickness (with shims)also affects how tight the axles fit, when set up properly the pin barely clears the axle shaft buttons.

Setting up the carrier is as detailed as a ring and pinion if you want it right.

[randy500]

When the discs are bad they have smooth spots, blue spots or are broken, or a ridge where they mesh.

[72LB]

Originally Posted by randy500

I normally re use the steel discs unless broken or extremely worn and just install new Guides, the half moon pieces, and shim it all up.
You can still buy steel disc and shim kits.

Your discs look fine.
What happens is each disc wears a little then there is lots of play in the spider gears. Use shims to get it in tolerance .001 to .005

The center pin gets worn too where it goes through the carrier.
And the shims under the small gears get worn
The hole for the pin in the carrier gets worn too.
The side of the pin gets worn from the axle shaft.

THe clutch pack total thickness (with shims)also affects how tight the axles fit, when set up properly the pin barely clears the axle shaft buttons.

Setting up the carrier is as detailed as a ring and pinion if you want it right.

Well fudge now I'm back to square one. Most everything in this looks good with no real wear to speak of, as shiny as some of the discs look I assumed thats what was worn. I've done ring and pinions before, this is the first carrier overhaul I've done. Do they make a kit with just shims and guides?

[randy500]

Guides
https://www.justdifferentials.com/GM.../gm9778355.htm

Yukon Guides
YSPCG-00

Yukon shims
YPKGM12-PC-SHIM


Best Value and Price
Eaton 18 plate steel clutch kit with shims and guides
29403-00S

https://www.summitracing.com/parts/etn-29403-00s

[72LB]

Originally Posted by randy500

Guides
https://www.justdifferentials.com/GM.../gm9778355.htm

Yukon Guides
YSPCG-00

Yukon shims
YPKGM12-PC-SHIM


Best Value and Price
Eaton 18 plate steel clutch kit with shims and guides
29403-00S

https://www.summitracing.com/parts/etn-29403-00s

Randy thanks for the links, justdifferentials seems to have some decent prices. I looked at that clutch kit Summit has last night and might go that way since it's apart.

[jmlloar]

don't forget to use lube that is rated for limited slip.

[72LB]

Originally Posted by jmlloar

don't forget to use lube that is rated for limited slip.

80w90 and a bottle of GM limited slip additive.

[jmlloar]

Used to have to put additive into new dodge trucks from the factory. Seams some of them chattered and some didn't. this usually solved it.

[72LB]

It's been hard to find at times but the GM additive is good stuff.