Transmission Filter Inspection Finding

[Skyhawk13205]

I recently accomplished my transmission filter change, when I pulled it, I cut open the filters to see if there was metal and I found a bit, most metal was ferrous flakes smaller less than .002, some brass shaving about .0025x.125” and longer ferrous shaving about .0020x.25”. This was the filter change at 2000miles at 36 month per Allison recommendation for normal duty running on a TES-295 fluid.

When I first got the truck from auction I replaced the filters and did not find any metal.

I was wanting to find out what other people have found. The trucks has about 8.2K on the odometer, but ECM data shows about 12k.

I could not find an Allison transmission resource in filter inspections for a high material count, based on my experience with aircraft maintenance and hobby automotive work this would be a moderate to high level of metal contamination.

Ref attached pictures, the washer is about a quarter’s size. I could not find a quarter or change prob because I spent it all on my truck.
Thank for your input.

 

[Suprman]

If you take the line off the tcase that goes to the scav pump once the line is off you can unscrew a catch screen. Look there for debris.

 

[GeneralDisorder]

Yeah - what he said

The most common issue with these is the C6 thrust bearing in the transfer case. When they fail they shotgun needle bearings through the trans and they end up in that scavenge line among other places. The updated part from Allison is a solid plastic bushing in place of the needle bearing assembly.

That issue is one of the reasons I like the ECO hubs. Hopefully between halving the RPM of the transmission, running it slower and cooler, and switching to synthetic Dex VI ATF I won't ever have to deal with that nonsense. Not sure when or if Allison addressed this in these trucks. I'm sure the majority of the A1P2's got the fix but I don't think any of our soft cab trucks got it. Would love to see some information on transmission serial number ranges and what updates they had.

 

[Skyhawk13205]

Yeah - what he said

The most common issue with these is the C6 thrust bearing in the transfer case. When they fail they shotgun needle bearings through the trans and they end up in that scavenge line among other places. The updated part from Allison is a solid plastic bushing in place of the needle bearing assembly.

That issue is one of the reasons I like the ECO hubs. Hopefully between halving the RPM of the transmission, running it slower and cooler, and switching to synthetic Dex VI ATF I won't ever have to deal with that nonsense. Not sure when or if Allison addressed this in these trucks. I'm sure the majority of the A1P2's got the fix but I don't think any of our soft cab trucks got it. Would love to see some information on transmission serial number ranges and what updates they had.

My truck is not in the SN range for the first bearing update, so it has the updated thrust bearing but not in the final update where the composite thrust washer was used.

see attached Allison service letters regarding c6 bearing updates

As far as know there were 3 bearing used. The original one is the bad one that destroys the transfer case.

My personal opinion is the C6 thrust bearing failures are partly due to the vibration issue from the driveline angle and high RPM, this problem was only reported on the 4x4 based on me watching the forums.

Most of the material was on the lube filter not the main. I am trying to figure out where the lube filter gets it’s supply from.

 

[Keith Knight]

By the way what is recommended fluid fiter ad change recommend using synthetic DEX?

 

[Skyhawk13205]

By the way what is recommended fluid fiter ad change recommend using synthetic DEX?

With an approved tes-295 fluid, it is 36 months for filter, and 48 month for fluid. Non approved is 12 months for fluid and filter.
Please ref Allison service letter 10-tr-99

 

[Keith Knight]

What do you guys think of TES 668?

 

[Ronmar]

If you take the line off the tcase that goes to the scav pump once the line is off you can unscrew a catch screen. Look there for debris.

You should see something on the tcase drainplug if it is that C6 thrust bearing.

Allison wants a small fortune for that composite washer:O

 

[GeneralDisorder]

My personal opinion is the C6 thrust bearing failures are partly due to the vibration issue from the driveline angle and high RPM, this problem was only reported on the 4x4 based on me watching the forums.

Interesting! Glad I have the high pinion 4x4. I had not noted the correlation of the 4x4 low pinion rear with failure reports. I'll have to watch for that on any future reports I see. And yeah the driveshaft angle thing is an unfortunate design flaw. Still - the ECO hub should improve the chances of not seeing that effect along with driveshaft balancing.

 

[GeneralDisorder]

As a point of reference my 2008 A1R transmission serial number is 6510807894. The final part number change occurred at 6511014364 so it's safe to assume that basically none of the civilian trucks have the latest composite thrust washer and being the first change was in 2007 and they don't even discuss the MD3070 only the 3700SP - that essentially means that only very late A1R's got even the first revision. I hope the first revision wasn't actually WORSE than the original bearing

I'm gonna pretend the first revision was AWESOME but just too expensive so someone had the bright idea to make it from a solid chunk of plastic to reduce cost.

 

[aw113sgte]

As to long as you don't have anything in the way, the bearing swap is very easy.

 

[GeneralDisorder]

As to long as you don't have anything in the way, the bearing swap is very easy.

My M1079 box subframe has a tubular cross-member that is right behind that cover. I could easily pull the box off but the subframe is huck-bolted in place and so is the cross-member. I could cut the cross member huck bolts and just use normal bolts to reinstall it. Probably wouldn't be too bad with the box removed.

 

[Skyhawk13205]

Pulled the screen, found some steel qurily qs and some non ferrous metal but no roller bearings and no brass pieces, drained about 2 gallons from the transfer case, drain plug just had normal fuzz. I recently installed a PTO and I think that might be the cause, I plan on pulling it and inspecting it to check the gear end play.

 

[Ronmar]

Could have been the PTO gears wearing in…

 

[Ronmar]

My M1079 box subframe has a tubular cross-member that is right behind that cover. I could easily pull the box off but the subframe is huck-bolted in place and so is the cross-member. I could cut the cross member huck bolts and just use normal bolts to reinstall it. Probably wouldn't be too bad with the box removed.

mine is already separated and that upper frame rail(now my floor assembly) is still light enough to be lifted… Have you sourced that part?

 

[aw113sgte]

My M1079 box subframe has a tubular cross-member that is right behind that cover. I could easily pull the box off but the subframe is huck-bolted in place and so is the cross-member. I could cut the cross member huck bolts and just use normal bolts to reinstall it. Probably wouldn't be too bad with the box removed.

Can you cut the hucks and just slide the crossmember rearward, not removing the box?
Wonder why my m1096, that had a box on it, does have any crossmembers at all on the upper rail?

 

[Skyhawk13205]

Took my PTO back off to check for metal. The PTO seems fine, spins well, slight endplay on the input gear, dumped the oil from the PTO housing into a clean bin and it looks like the same material I found in the lube and scavenge filter. The PTO I took from a parts truck that had about 10k miles and it looks like it was original to the truck. I am not sure if it is worth the time of taking apart the PTO to check for wear. I am thinking maybe the PTO is just wearing in like Romar commented.

 

[GeneralDisorder]

IDK - those big pieces in the pan don't strike me as break in materials. Break in materials might give the oil a little swirl in the right light. They usually can barely be seen with the naked eye if at all, and you definitely can't feel them. Just my opinion from a lifetime in the shop.

 

[Ronmar]

On my 1079 chassis, the tubular crossmember in the main frame looks to be far enough to the rear to clear the P6 clutch housing. At any rate, 8 Huck bolts and a hydraulic jack to spread the frame a hare and it could be slid to the rear..

It is the welded in Channel in the upper frame rail that will be the issue.

you either need to separate the frame rails(quite a bit of work) and lift the upper frame, or cut it out and weld or bolt it back into place after the job is done...

 

[GeneralDisorder]

Yeah on further inspection it is the welded cross member that is in the way. Will probably just cut it out and bolt in a replacement if I decide to go in there.