Live action from FUMANCHU182.

[Unholy707]

Yeah this is making me lean towards the 9” conversion with swappable center sections

 

[fumanchu182]

Okay so there is a 100% all stop to this. By removing the pinion I lost all references needed for re-assembly. In addition to this ZF does not publish the pre-load needed so that the crush sleeve can be correctly set. Also a crush sleeve like a axle/pinion seal is one time use only. Re-using it again and you run the risk of crushing the bearing in the race. No thanks.

ZF nor dodge sell crush sleeves as from what I can see on store.mopar.com. I have two options. Use another differential that is brand new, drain, pull the entire center section out, remove ring, go to town.

I have another option. @zhc kindly sent me a differential out of the charger, it was in good condition when removed. Drain, rip out center section, remove ring, leave pinion. Prior to this measure backlash. Would avoid pinion issues.

I have reached out to

to see if they have a solution for Hellcats or something that may work. Right now eating dinner so I will take my measurement tools to it in a bit to get dimensions. Also a very good option to the crush sleeve, you can torque to hell and it's not going to become useless.

I have a sneaking suspicion is that ZF/Dodge built these to be not re-pairable.

 

[16GoManGoHC2]

I knew unfortunately it couldn’t be easy
Somebodies got to know.

 

[oilburner]

Okay so there is a 100% all stop to this. By removing the pinion I lost all references needed for re-assembly. In addition to this ZF does not publish the pre-load needed so that the crush sleeve can be correctly set. Also a crush sleeve like a axle/pinion seal is one time use only. Re-using it again and you run the risk of crushing the bearing in the race. No thanks.

ZF nor dodge sell crush sleeves as from what I can see on store.mopar.com. I have two options. Use another differential that is brand new, drain, pull the entire center section out, remove ring, go to town.

I have another option. @zhc kindly sent me a differential out of the charger, it was in good condition when removed. Drain, rip out center section, remove ring, leave pinion. Prior to this measure backlash. Would avoid pinion issues.

I have reached out to

to see if they have a solution for Hellcats or something that may work. Right now eating dinner so I will take my measurement tools to it in a bit to get dimensions. Also a very good option to the crush sleeve, you can torque to hell and it's not going to become useless.

I have a sneaking suspicion is that ZF/Dodge built these to be not re-pairable.

correct there like a bic lighter, throw away if there`s an issue.
when I replaced mine I found there was next to no preload but zero end play just from feel. if I was doing yours I would tighten till zero end play an tighten a bit more till you feel slight load on pinion rotation an if the brgs feel smooth your good to go. I set my back lash at .004th with zero side to side carrier movement played with the shims on snap ring side till I got slight resistance in carrier rotation. my diff is much quieter than the diff was from new. still makes some noise but much better. will find out how well it works at the track next month.

 

[oilburner]

make sure to use thread lock with your pinion nut.

 

[fumanchu182]

correct there like a bic lighter, throw away if there`s an issue.
when I replaced mine I found there was next to no preload but zero end play just from feel. if I was doing yours I would tighten till zero end play an tighten a bit more till you feel slight load on pinion rotation an if the brgs feel smooth your good to go. I set my back lash at .004th with zero side to side carrier movement played with the shims on snap ring side till I got slight resistance in carrier rotation. my diff is much quieter than the diff was from new. still makes some noise but much better. will find out how well it works at the track next month.

I will make a decision tonight on this, I want this diff done so I can go racing. Trying to make it to MIR this weekend coming up. I wish I had a CNC machine so I could just go cut some steel and buy shims down the road and make this happen. I honestly think that is the best thing to do in this instance. If anyone has a TBA Machine one piece can you chime in here. How did you set pre-load on the pinion. @hellno when you setup yours what was the procedure like?

 

[Unholy707]

Man that sucks smh what a bunch of bologna, sorry to hear that man glad @zhc is taking care of you

 

[catdad]

The pinion crush sleeve was the weak point of the 8 3/4 back in the day. I remember someone made a kit with a solid bushing and shims. maybe something like this can be made.I can check bearing preload as I have a 3.09 and a 2.62 spare. It will be late tomorrow though.

 

[fumanchu182]

grabbed dimensions while i was searching

look familiar? https://www.summitracing.com/parts/mop-3507678#overview
However would like a sleeve eliminator

 

[catdad]

I think I used the one from mancini racing back then Looks like this

 

[fumanchu182]

So I am once again in believe that dodge/zf engineered these to be non replaceable. the shaft has a taper and then at the bottom of the taper an 1/8th of an inch is machined out so you cannot place shims at the bottom and is required for a kit like that.



if you were to make a crush sleve eliminator then it would have to be machined in such a way that the bottom would fit at the taper and then the top hole machined to the rest of the shaft


i wish I had a cnc machine 😂

 

[Unholy707]

Sounds like promise of supply/demand down the line when millions of cars produced need a new one

 

[fumanchu182]

@Unholy707 and I have been talking about CAD work and I'm like I'm such a goonie right now. Fired up solidworks:


Top of shim has 1.440 ID

Bottom of shim has 1.54ID. Whole body has 1.71OD.

Shelf for shims to rest against is 1/8" thick. Tolerances were left a little loos by .001 for fluid

I went with a overall height of .942" as that seems to be the middle of the road. Shims would be custom sourced to match the shelf ID/OD (37mm id, 44mm). Just in case shims would be in a five pack: 5 * .001 = 0.005 of play. I thought about ten thou: .0001 for play but that is ridiculous. This is not really that precise in nature and a guesstimate at best. Thoughts? Going to contact the local makerspace tomorrow to see if someone can rough it out if I got pick up some stock at the metal supply place.

 

[fumanchu182]

Visualizing the shelf. Good fight, good night. Also asked on the MSHS group on FB if anyone else has done this before I re-invent the wheel...

 

[oilburner]

The pinion crush sleeve was the weak point of the 8 3/4 back in the day. I remember someone made a kit with a solid bushing and shims. maybe something like this can be made.I can check bearing preload as I have a 3.09 and a 2.62 spare. It will be late tomorrow though.

if your units are complete assembled diffs you will not be checking pinion brg preload. your checking how much it takes to rotate the whole diff. carrier included.

 

[hellno]

I will make a decision tonight on this, I want this diff done so I can go racing. Trying to make it to MIR this weekend coming up. I wish I had a CNC machine so I could just go cut some steel and buy shims down the road and make this happen. I honestly think that is the best thing to do in this instance. If anyone has a TBA Machine one piece can you chime in here. How did you set pre-load on the pinion. @hellno when you setup yours what was the procedure like?

HOPEFULLY YOU CAN HEAR THIS i was able to get a new crush sleeve (4 of them) which i used two sent @Hatermkr one and i believe i sent a j one as well ,you are correct you cannot buy parts for these differentials' i was lucky to have met someone who had a friend at the zf factory to get them ,and it sucks because these billet diffs being made they are reusing the original crush sleeve and adding shims to it (i personally think thats a rig job).i put my prload at 30 "" pinion only no carrier ( i know that seems like alot but when your putting down all that torque ive found under heavy load situations it works best ) and i set my back lash at 8 being the last time i built my billet diff i installed the true trac as well ,,as most know these diffs (especially the 3.09) tend to get very noisey ,racing it didnt bother me at all ,your better off leaving the pinion alone and just setting back lash and letting it rip

 

[Unholy707]

Wouldn’t it be awesome though if someone could develop a crush sleeve like @fumanchu182 is looking into and that actually solved the noise problem?

 

[hellno]

I SPOKE TO TODD @TBA ABOUT THE CRUSH SLEEVE CONCERNS

 

[fumanchu182]

pulling the plug on this diff disassmble. Going to use the diff Z gave me and start cleaning it out tonight. Will work with someone on getting a crush sleeve eliminator built.

 

[hellno]

pulling the plug on this diff disassmble. Going to use the diff Z gave me and start cleaning it out tonight. Will work with someone on getting a crush sleeve eliminator built.

thats not a bad idea ,i like how ford 9 inch had a selectable spacer that makes it fairly simple and not having to worry about a crush sleeve