M1078 A1 transfer case

[InvictusDecretum]

yep, those P6 assemblies should come right off without that crossmember. i got a quote from Allison for $430 for that composite washer. At that price I am tempted to engineer and machine my own...

Wow. That is the most expensive washer I think I've ever heard of... I am now a little bit more prepared for sticker shock when/if the guy calls me back. For that price I'm tempted as well. I wonder how one printed from PPA-CF would perform...

 

[aw113sgte]

What?? I bought mine from my local Allison dealer for something like $150, less than a year ago.

 

[aw113sgte]

Wow. That is the most expensive washer I think I've ever heard of... I am now a little bit more prepared for sticker shock when/if the guy calls me back. For that price I'm tempted as well. I wonder how one printed from PPA-CF would perform...

I wouldn't ever consider trying to make your own, because if it fails, there goes ten thousand bucks. 3d printing also has terrible tolerance and strength compared to non printed parts.

 

[InvictusDecretum]

I wouldn't ever consider trying to make your own, because if it fails, there goes ten thousand bucks. 3d printing also has terrible tolerance and strength compared to non printed parts.

I'm going to buy one if I can... but PPA-CF is a pretty incredible filament. We sinter in nylon at work, as well as metal sinter up to 316SS, and I'd say that PPA-CF is somewhere between the two. Has something like 24,000PSI tensile strength, almost exact dimensional printing, great layer adhesion, chemical resistant, can be submerged in water... it's nuts.

I suppose I could CNC mill one out of aluminum instead but... yeah. I assume allison tried all this and ended up with their composite for a reason. Hopefully they call me back with $150 and not $450.

 

[Ronmar]

I wouldn't ever consider trying to make your own, because if it fails, there goes ten thousand bucks. 3d printing also has terrible tolerance and strength compared to non printed parts.

$150, cool, order me one will ya.

Since they replaced what looked like ~1/8-3/16" thick roller thrust bearing unit with a ~ 1/4-5/16" composite washer(4.9mm >3/16" thicker than original part), i am thinking the only real critical tolerance is going to be the diameter. Need a temperature and oil tolerant composite or light metal(aluminum or bronze perhaps) since the adjacent surfaces appear to be steel. Allison probably settled on composite as it was cheaper to manufacture... I could probably turn one of these out in aluminum on the lathe in an hour or so?

That is I believe the point of the composite, The original was getting hammered either when the P6 engages or disengages(1st gear) until failure.. The composite can wear or even fail and it should do no serious damage to the rest of the transmission unlike the hardened rollers and cage of the original thrust bearing assembly that chewed their way thru the C6 clutch pack and aluminum housing in this failure example...

 

[aw113sgte]

$150, cool, order me one will ya.

Since they replaced what looked like ~1/8-3/16" thick roller thrust bearing unit with a ~ 1/4-5/16" composite washer(4.9mm >3/16" thicker than original part), i am thinking the only real critical tolerance is going to be the diameter. Need a temperature and oil tolerant composite or light metal(aluminum or bronze perhaps) since the adjacent surfaces appear to be steel. Allison probably settled on composite as it was cheaper to manufacture... I could probably turn one of these out in aluminum on the lathe in an hour or so?

That is I believe the point of the composite, The original was getting hammered either when the P6 engages or disengages(1st gear) until failure.. The composite can wear or even fail and it should do no serious damage to the rest of the transmission unlike the hardened rollers and cage of the original thrust bearing assembly that chewed their way thru the C6 clutch pack and aluminum housing in this failure example...

I'd be happy to, I didn't keep the receipt unfortunately so I'm not sure if it was the same p/n. It was the composite bearing though. I was surprised by the thickness change and it threw me for a bit of a loop during install.
I'd try some other dealers, it is possible they changed the price recently but seems doubtful.
Using another material, especially polymers is very complicated. The wear characteristics, strength, temp tolerance, creep, CTE. This was a huge challenge for Allison engineers so I wouldn't even bother trying to reengineer that wheel.

 

[Ronmar]

I did two request for quote today, the one from excaliber came back today $380… that first one was thru the allison western region rep supplied out of portland…

 

[GeneralDisorder]

Military pays $235 and some change as of Jan '24 for that part.

 

[InvictusDecretum]

With NC tax and a mandatory $60 freight charge since Allison is the only place I can seemingly get it (dealers/distributors don't have it anywhere on the east coast, 3 different ones all saying same thing), it's $460.

The dude was shocked at how much it cost. Like, he was warning me to be prepared and said "for a plastic washer..."

 

[InvictusDecretum]

A small contribution to the community (full memo and literature, courtesy of my awesome local Allison rep):



It's part # 28 on my SN diagram:

 

[Ronmar]

I'd be happy to, I didn't keep the receipt unfortunately so I'm not sure if it was the same p/n. It was the composite bearing though. I was surprised by the thickness change and it threw me for a bit of a loop during install.
I'd try some other dealers, it is possible they changed the price recently but seems doubtful.
Using another material, especially polymers is very complicated. The wear characteristics, strength, temp tolerance, creep, CTE. This was a huge challenge for Allison engineers so I wouldn't even bother trying to reengineer that wheel.

I doubt this was much of a challenge for allison beyond the fact that they probably realized that they put a short thrust bearing in a tall cavity... Babbet and composite thrust washers are common in automatic transmissions to position planetary gear assemblies. The new one is nearly 3 times as thick?

"Adequate clearance is provided in the existing design to allow proper installation", IE: I think they screwed up...

Looking at all the pics and drawings, it appears to me the bearing rides on the stationary center tower that the piston rides on and which holds the center shaft end pilot bushing in the P6 cover. The other surface of the thrust bearing appears to interface with the back side of the spinning center splined assembly that rides on the center shaft. I suspect the original bearing with all that gap could get smacked by the heavy splined center assembly, perhaps in conjunction with the P6 piston release when you shift out of 1st...