two small metal teeth on transfer case drain plug

[Zach_M1078A1]

I am doing an oil change on the transmission and found these on the magnetic drain plug to the transfer case. Oil looked clean and no shavings. Don’t know if this is the initial service or if it was done before it has 28,000 miles and is direct from govplanet.

 

[GeneralDisorder]

Looks like part of a bearing cage to me. I would clean them better and try to get a closer look. Digital microscope would be handy if you happen to have one or know someone that has one (used often in electronics repair).

Also send some of the old fluid for analysis.

What else was on the drain plug? Any fine shavings?

In the Army, fluid and filters are part of the annual service. So it *should* have been done at least a few times even if they pencil whipped most of them. That said my truck is a 2008 and DEFINITELY never had a transmission service - but it also had 2045 miles on it during it's military career. With 28k I've got to believe that belonged to an active duty unit and got used and very likely serviced.

 

[Zach_M1078A1]

Here are some more photos.
Oil looks dark, gray In the bucket but looked light brown coming out of the transfer case. The kind of light brown that new motor oil has not water and oil mixed up to make a light brown color

 

[Zach_M1078A1]

The oil fuel and air filter had a sharpie date of 2014 so I know that they were serviced. I just don’t know if they did the transmission. There weren’t really any black Ultrafine shavings just those two pieces of metal. I also slowly dumped the oil from one bucket into another bucket to see if there was anything in the bottom of the bucket that came out with the Oil but there wasn’t anything else in there

 

[GeneralDisorder]

Still reminds me of a section of a bearing cage.

Send a sample of the oil in for analysis.

 

[Zach_M1078A1]

Still reminds me of a section of a bearing cage.

Send a sample of the oil in for analysis.

If it is a piece of a Bearing cage but everything seems to work fine what is the prognosis? What am I supposed to do? With this is com from the transmission into the transfer case with the fluid when you say Barry in cage, do you mean a thrust bearing?

 

[87cr250r]

If it's a piece of a bearing cage do not drive. Without the cage, the rollers will fall out of the bearing and the transfer case may be catastrophically damaged.

 

[GeneralDisorder]

No - tapered roller bearing - I mean yeah they have a thrust component to what they do but it's not what most people think of when you say "thrust bearing".....

Bearing cage:

They come in thousands of sizes - they are integral to the bearing and generally aren't removable on their own:

Obviously the first one shown is obliterated.

Prognosis is unknown without knowing for sure what it came from. If it is a bearing it will eventually drop more crumbs to be found on the magnet and over time could lock up or come apart and go into other components - breaking gears, being jammed between something and the case and blowing a hole in the case or fracturing it. Could lock up the whole transmission at speed. Anything and everything you can think of could happen.

Oil analysis might tell you something. It's odd there's no forest of shavings on the drain plug magnet. That might point to a failure from quite a while ago and just now these two bits have found their way to the magnet while the rest was removed over several fluid changes. The grey color of the fluid says there's probably something for analysis to tell you......

 

[Zach_M1078A1]

Who does oil analysis?

 

[Zach_M1078A1]

They look exactly like the pieces in that first photograph

 

[Zach_M1078A1]

That being the case, what is the cheapest way for me to fix this?

 

[87cr250r]

If only one side of the cage is busted the spacers may still be between the bearings. As the cage breaks apart further all of the rollers bunch up on one side. This causes the shaft to go out of alignment and can break the gears or the transfer case housing if it occurs at speed. This can do major damage and possibly lock the case up.

 

[Zach_M1078A1]

Are you saying that for those to be in the transfer case they couldn’t have come from the transmission. If yes, is it possible for me to just drop the transfer case take it apart and find the damage bearing. Or take the transfer case to a local Allison shop in Salt Lake. I don’t know logistically how to get the entire transmission with their integrated transfer case out I’m guessing it weighs about 1000+ pounds I live on the top of a mountain and if I’m not supposed to drive at this kind of puts me in a spot and did I mention, I am totally broke

 

[Ronmar]

I agree with general, looks like a cage for the thrust bearing.. on the passenger side of the transfer, there is a port with a hose that runs up to the scavenger pump On the passenger side of the trans housing. If you remove that line and the fitting that connects the line to the transfer case, you should find a mesh screen filter That keps debris out of the scavenger pump. I suspect you will find more parts in that strainer… This is a possible issue and they directed that bearing be changed at any point the trans was going to be worked on. its all the way up under the case behind the P6 clutchpack all the way at the back end of the trans/transfer.

you cannot remove the transfer, or even that P6 clutch cover with the transmission installed, without cutting crossmembers out of the way… there are 2 shafts(one inside the other, output and P6 clutch that gives us first gear) that extend all the way back to the rear of that clutch housing, so the transfer has to move quite a ways to the rear to clear those shafts…

here is that filter on the 24p parts diagram… The thrust-bearing that fails is located where the arrow is…

 

[GeneralDisorder]

The summary to what Ronmar just posted is: "Install a new or remanufactured transmission" if you need this thing road-worthy in the short term.

Or find a VERY WELL QUALIFIED Allison rebuild shop and pull the transmission/t-case for them or have them do it.

My sources in the military say they always pull the bed/box off for transmission swaps if at all possible and use an overhead crane. The transmission/t-case assembly is over 1,000 lbs.

 

[Zach_M1078A1]

I agree with general, looks like a cage for the thrust bearing.. on the passenger side of the transfer, there is a port with a hose that runs up to the scavenger pump On the passenger side of the trans housing. If you remove that line and the fitting that connects the line to the transfer case, you should find a mesh screen filter That keps debris out of the scavenger pump. I suspect you will find more parts in that strainer… This is a possible issue and they directed that bearing be changed at any point the trans was going to be worked on. its all the way up under the case behind the P6 clutchpack all the way at the back end of the trans/transfer.

you cannot remove the transfer, or even that P6 clutch cover with the transmission installed, without cutting crossmembers out of the way… there are 2 shafts(one inside the other, output and P6 clutch that gives us first gear) that extend all the way back to the rear of that clutch housing, so the transfer has to move quite a ways to the rear to clear those shafts…

here is that filter on the 24p parts diagram… The thrust-bearing that fails is located where the arrow is…

View attachment 896963

That crossmember appears to be bolted in and not welded and has room behind it to be slid further back between the frame rails and out of the way, can that clutch cover be removed then and have the bearing replaced with the new composite bushing from that cover access?

 

[GeneralDisorder]

Interesting post dealing with the issue you are potentially dealing with. Looks like Allison changed the bearing to a "composite bushing".... lots of details if you are experiencing this issue:

M1078 A1 transfer case

Had some codes come up the other day on the transmission 2511, 2533, 5633. I pulled a cover that is next to the output shaft going to the rear axle. From what I can tell the gears look fine but something probably a bearing came apart and bounced around and you can see where the parts were...

www.steelsoldiers.com

 

[GeneralDisorder]

If you can pull the cover with the transmission installed I would definitely do that to gain more perspective and information.

 

[Ronmar]

I think if you look closer you may find there are 2 crossmembers, one in the subframe above the main frame… that may depend on the model truck we are dealing with though. The 1079 subframe has a welded member there, about 3 inches behind the transmission. you would have to remove a bunch of hardware to slide the bolt in member, providing it will even move(may have to make a gap with a bottle jack… it will be a bit of work for sure

yes, the thrust washer is right behind the cover. Read thru the linked discussion General provided, that was a great discussion, those folke documented everything they did very well. And as they suggested best to talk to Allison with your trans S/N to confirm parts applicable. For instance that part no for the old bearing isnt listed anywhere in the 24P manual…

 

[Zach_M1078A1]

I think if you look closer you may find there are 2 crossmembers, one in the subframe above the main frame… that may depend on the model truck we are dealing with though. The 1079 subframe has a welded member there, about 3 inches behind the transmission. you would have to remove a bunch of hardware to slide the bolt in member, providing it will even move(may have to make a gap with a bottle jack… it will be a bit of work for sure

yes, the thrust washer is right behind the cover. Read thru the linked discussion General provided, that was a great discussion, those folke documented everything they did very well. And as they suggested best to talk to Allison with your trans S/N to confirm parts applicable. For instance that part no for the old bearing isnt listed anywhere in the 24P manual…

Thank you!