M1078A1 "Pandora" Build | 2024-??? | ***Picture Heavy***

[aw113sgte]

Amazing how one little seal can cause so much grief

 

[Aviator4x4]

Well, I got all the parts cleaned up as best I could. Auto transmissions are wizardry, I swear.








The entire valve control bodies disassembled with only 4 tools:

10mm socket​

4mm Allen​

3/32 punch​

Small hammer to tap the pins out​

Collecting new gaskets, O-rings, and a suction filter kit from my allison dealer then on to reassembling it.

I ohmed out all of the solenoids per the TM, and every one was at 3.3Ohm minus the bottom right one in first picture, which was a 3.4Ohm. TM states, "resistance should read between 2.0-5.0 ohm on a 10 ohm scale." so calling those good (no issues with them before tear down).

Solid 10% chance this works, ever again, but good experience and have learned a lot.

 

[Ronmar]

Any sign of water at the transfer case drain?

 

[Aviator4x4]

Any sign of water at the transfer case drain?

... yup :/

Well, emulsified oil on the bottom with a little bit of brown oil on top/last out from drain.

What are your thoughts on that ? Is what I'm doing even worth it ?

 

[Aviator4x4]

Well, I got the C6 housing cover off using the 4x4 brace method suggested here:

M1078 A1 transfer case

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...

www.steelsoldiers.com

Only needed to lift it a couple inches so I could pull the cover back.



When I removed the C6 clutch housing, non-emulsified oil came dribbling out. I'm hoping that's a good sign.





Looks like I am going to replace these bolts since their sacrificial zinc coating is gone. Really interesting assortment haha. Glad the long non-standard one is in good shape.

 

[Ronmar]

The glue that binds the clutch media to the discs is water soluble.

I guess it depends upon how long it has been since it was first run and the water mixed/emulsified with the oil. if it has set like that with emmulsified oil for long, the C7 difflock clutch pack may be toast as i believe it is mostly immersed in fluid when not running.

The oil level in the main trans body should be between 1.8" cold and 4" hot above the line where control module bolts to trans housing, so the main clutch disks should only see the emmulsified oil when running...

 

[Ronmar]

thrust bearing pics?

 

[Aviator4x4]

The glue that binds the clutch media to the discs is water soluble.

I guess it depends upon how long it has been since it was first run and the water mixed/emulsified with the oil. if it has set like that with emmulsified oil for long, the C7 difflock clutch pack may be toast as i believe it is mostly immersed in fluid when not running.

The oil level in the main trans body should be between 1.8" cold and 4" hot above the line where control module bolts to trans housing, so the main clutch disks should only see the emmulsified oil when running...

Disappointing to hear but will continue on. It's been 12months since I put fresh oil in it, 8 months since I drove it, and ~3mo since I ran it. I'm also concerned about the torque converter, but hoping that there is some drainback for both C7 and the TC.

thrust bearing pics?

Incoming shortly good sir.

I literally pulled the housing 20mins ago, came inside to hydrate and read the TM on C6 housing disassembly, and now back to the garage.

 

[Aviator4x4]

thrust bearing pics?

Thrust bearing pictures and also some clutch pack pictures. Not sure how I want to clean those clutches so I haven't yet, just wiped down the reaction plates and set them out.

I test fit the new thrust washer, then removed it to parts clean the C6 clutch housing since I'm sure I got some gasket pieces in there while scraping, despite my efforts to keep them out.

 

[Ronmar]

Can you shoot a pic of the side of the plate carrier/center component that engages the forward face of the thrust bearing? i am curious what it looks like.

Based on the radically different thickness between the thrust bearing pack and the thrust washer I am thinking that once Allison started seeing the thrust bearing failures they realized they had made a mistake, and that the gap back there probably allows for some acceleration of that heavy center component, perhaps when you release the P6 clutch/shift out of 1st gear, or perhaps when you shift between R and D(Center shaft fore-aft movement from helical gears when P3 bearing carrier reverses directions). The gap left room for acceleration and impact by that heavy center section with the roller thrust-bearing…

 

[Aviator4x4]

Can you shoot a pic of the side of the plate carrier/center component that engages the forward face of the thrust bearing? i am curious what it looks like.

Based on the radically different thickness between the thrust bearing pack and the thrust washer I am thinking that once Allison started seeing the thrust bearing failures they realized they had made a mistake, and that the gap back there probably allows for some acceleration of that heavy center component, perhaps when you release the P6 clutch/shift out of 1st gear, or perhaps when you shift between R and D(Center shaft fore-aft movement from helical gears when P3 bearing carrier reverses directions). The gap left room for acceleration and impact by that heavy center section with the roller thrust-bearing…

I can get you better pictures later, but this thing ?

 

[Aviator4x4]

Can you shoot a pic of the side of the plate carrier/center component that engages the forward face of the thrust bearing? i am curious what it looks like.

Based on the radically different thickness between the thrust bearing pack and the thrust washer I am thinking that once Allison started seeing the thrust bearing failures they realized they had made a mistake, and that the gap back there probably allows for some acceleration of that heavy center component, perhaps when you release the P6 clutch/shift out of 1st gear, or perhaps when you shift between R and D(Center shaft fore-aft movement from helical gears when P3 bearing carrier reverses directions). The gap left room for acceleration and impact by that heavy center section with the roller thrust-bearing…

Some interesting, uneven, wear scars on the inside of the 2nd gen thrust washer as well.

 

[Ronmar]

I can get you better pictures later, but this thing ?

View attachment 937879

View attachment 937878

View attachment 937877

Yep, that thing(splined hub). Looks like a pretty substantial chunk of steel... Idea on how much it weighs?

 

[Aviator4x4]

Yep, that thing(splined hub). Looks like a pretty substantial chunk of steel... Idea on how much it weighs?

Don't have a precise way of weighing it, unfortunately. Utilizing weight comparison, that 5# dumbbell + fat gripz was similar, so I'd guess in the 6-8# range.

10# was too heavy, 5# was too light, but was closer to 5 than 10.

 

[fukiphino]

Subscribing to this. Good idea for paint on the wolverine pump. After my first winter outside, no driving even, it's rusted.

 

[Aviator4x4]

Subscribing to this. Good idea for paint on the wolverine pump. After my first winter outside, no driving even, it's rusted.

Hopefully this transmission thing isn't the end of my story ! I believe I have ordered all the parts needed from my local Allison rep to get it back together, but who knows how long they'll take to get in (one is probably backordered, or something).

Once I have everything in my hand, I think this is what I'm going to do:

 

[aw113sgte]

What is "add flush"?
Anecdotal, but my trans had 15w40, I pulled the return line(at trans) and let the truck run till it spit some air. Filled with transynd 668 and ran till red started pushing out the hose. Then reconnected and filled to appropriate level. It worked well for me, although I didn't notice a difference in shifting performance. I mainly did it because it gets cold here and 15w40 is a very poor performer at temps below freezing.

 

[GeneralDisorder]

Yeah I wouldn't bother with any of that. Waste of time and fluid.

Drain trans and transfer case. Change filters and fill with new fluid ( ATF - The Army uses Dexron VI ). Disconnect return line from cooler and run the engine till you see red fluid. Fill to capacity. Done.

Don't pour any kind of "flush" in that transmission. Most of that type of product is pure snake oil.

 

[Aviator4x4]

What is "add flush"?
Anecdotal, but my trans had 15w40, I pulled the return line(at trans) and let the truck run till it spit some air. Filled with transynd 668 and ran till red started pushing out the hose. Then reconnected and filled to appropriate level. It worked well for me, although I didn't notice a difference in shifting performance. I mainly did it because it gets cold here and 15w40 is a very poor performer at temps below freezing.

Yessir, planning on pulling the return and letting her pump out as much as she wants.

Flush is some liquified money AMSOIL engine+trans flush. I selected it since it's advertised for both engine and trans, and is an EG based product which is hygroscopic/miscible. I'm hoping a combination of those helps clean the forbidden milkshake out of my torque converter... but also fully realize it is semi snake oil to @GeneralDisorder point.

Im trying to dilute the milkshake with the two cheaper T4 changes before Transynd swap. Maybe salvage my C7 clutch pack but the TM seems to indicate it could be swapped while on the truck.

 

[Ronmar]

Yessir, planning on pulling the return and letting her pump out as much as she wants.

Flush is some liquified money AMSOIL engine+trans flush. I selected it since it's advertised for both engine and trans, and is an EG based product which is hygroscopic/miscible. I'm hoping a combination of those helps clean the forbidden milkshake out of my torque converter... but also fully realize it is semi snake oil to @GeneralDisorder point.

Im trying to dilute the milkshake with the two cheaper T4 changes before Transynd swap. Maybe salvage my C7 clutch pack but the TM seems to indicate it could be swapped while on the truck.

The C7 can, yes.