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M1078 Trans filters

BigMontana

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I think my trans filter is plugged up, the trans cooler that sits in front of the radiator does not even get warm...the trans is overheating.

I see only one filter number on the parts spreadsheet, but it looks like there are two places to change filters.

It says "filter change kit" in the parts spreadsheet, is there anything else I'm going to need other than fluid and that filter kit because I'm probably doing a call out and I'd like to tell them what to bring.

I was a little over full previously, because the mechanic who filled it last just did the filter and replaced what came out from transfer and main trans drain...and he over filled because didn't do it when running/hot.

(Yeah I saw callmecolt had the same issue).
 

BigMontana

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I'm not actually sure what your underlying thought in asking that question is, so I'll answer it twice:

(1) I want to flush the fluids and change the filters...It's an army vehicle, it's not rocket science.
Or
(2) the army manual from 2005 or earlier does not help me determine the contents of a box at NAPA auto parts in 2023.


did you download the manuals yet? ( first page / top of page / First Forum .. of this website

 

Skyhawk13205

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I'm not actually sure what your underlying thought in asking that question is, so I'll answer it twice:

(1) I want to flush the fluids and change the filters...It's an army vehicle, it's not rocket science.
Or
(2) the army manual from 2005 or earlier does not help me determine the contents of a box at NAPA auto parts in 2023.
I think WIX makes a filter kit for the Allison 3000 series. I want to say the filters are the same for a 2” sump.


Also you can just go to an Allison dealer and buy the filter kit, make sure you have your SN handy.

I think the filter kit should be 29558328, that is what I used 3 years ago.
 

coachgeo

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LMTV/FMTV Parts Spreadsheet - Google Sheets

This is on one of the stickie posts that are on the top of the LMTV forum page. Lots of information there and if you find parts not listed or that have changed part numbers share those on the post so this list is current. The trans filters NAPA part number is on this sheet.
That Sticky is where he got the part numbers.



....

I see only one filter number on the parts spreadsheet, but it looks like there are two places to change filters.
quick search of part number shows kit includes two filters
It says "filter change kit" in the parts spreadsheet, is there anything else I'm going to need other than fluid and that filter kit because I'm probably doing a call out and I'd like to tell them what to bring.
this answers your own question on why it was asked if you had down loaded/reviewed the manual yet...

Get tya though..... it is a PITA to get thru the PDF so to our own demise we avoid the TM. Have found at times for TM using... trick to use when near internet ...Search net using words that might result in particular pages of the TM that would be helpful to solving questions, to pop up in the results. For example..... net search for {service transmission LMTV M1078} with that search one result in the list is link to an actual page in a TM on changing transmission fluid. Using that gets you in the ball park inside the TM. Can trace forward and backward thru that web version of TM to dig deeper right from there.
 
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BigMontana

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Solinoid issue supposedly, we shall find out on Saturday.

So far I spent a few grand getting her road worthy, and have spent a few grand while on the road chasing down non critical issues...this is the first major issue, but the rig made it 1800 miles already and seems fine other than the trans issue at this point...hopefully it's a minor issue, if not the LMTV project may be on hold pending funding :cool:
 

BigMontana

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Yeah, i've found all these, i really appreciate the people like this heli cool and Colt, and Wes, even where they aren't doing the same thing i'm doing they get close enough to answer a lot of my questions. Other people on youtube it can be funny to watch them fight with their own tools and the laws of physics, and then since they're disassembling something i learn what i need to know by seeing the inside.

I think once i get back to Montana I'll end up doing the dex a/t thing with the trans/trasfer case fluids after a few paychecks...you know...if i don't end up needing a new trans this weekend...
 

BigMontana

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Polson, MT
For anyone looking for the answer to the original question the Wix part from the parts spreadsheet comes with two filters.

The FMTV/LMTV parts spreadsheet trans fluid capacity listed is probably the FMTV size trans pan/fluid capacity...my 1994 LMTV's Alison 3700 only seems to need about 5 gal after a drain and filter change to return to the full line.

I've found checking the level while running to be a total pain in the ass where I have a hard time telling if I'm looking at splash or looking at the actual fluid level. I'm normally a manual trans person, I know almost nothing about automatic transmissions other than the fact the introduction of them to big rig trucking is allowing the big trucking companies to hire dumber and dumber drivers.

So,
As a rule of thumb from an Alison trans mechanic the 100% cold and NOT running full level should be pretty close to "hot full" at that level during running conditions the trans sucks some fluid into the converter and other parts and that "loss" is then made up for by temp related fluid expansion.
 

GeneralDisorder

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Your transmission is the Allison MD3070.

The 3700SP wasn't introduced into the FMTV till about 2005 or so and always has the WTEC IV controller.

All of the transmissions fall under several service bulletins about the C6 clutch thrust bearing failing and bearing parts ending up various places. This would be my biggest concern - I would pull the scavenge pump elbow off the transfer case and inspect the screen for any debris.

Incidentally - any of these trucks that have not had the C6 thrust bearing->bushing upgrade I would highly recommend going to the ECO hubs as they will reduce the drivetrain speeds by half and perhaps prolong the life of these. Quite a few threads on this particular failure - for example:

 

Ronmar

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Define overheating? How are you determining/measuring that heat? Is it storing any codes?

when you drain and refill the oil there is still a considerable amount of oil left in the torque converter and galleries, cooling hoses and cooler and maybe some in the transfer case scavenger pump circuit. The only way to exchange that fluid is to run the trans and push fresh fluid thru it.

The same pump that creates the operational pressure also circulates fluid to the cooler. So if it is shifting and operating OK that pump must be OK. The basic flow is sump, strainer, pump, main filter, pressure reg. Here system pressure is available for the solenoids to work the clutches(Not much flow). The main flow from the reg is to the torque converter then out to the cooler(large heat source when converting), back from the cooler thru the lube filter and on to the lubrication circuit and ultimately back to the sump. When lockup is engaged(3-7th), a diverter bypasses most of the fluid from the TC and sends it straight to the cooler as it is no longer such a heat source.

probably the best place to look for trans temp is with an IR on the fitting where the oil exits the trans on its way to the cooler. I used those fitting temps when I was analizing where all the heat goes on the standard A0. The cooler is surrounded by jacket water from the raditor. If the thermostat is open, you will probably mostly feel cooled water off the bottom of the radiator.

if the trans is not over-full and heating oil hydraulically because its in the way, it is most likely something in the drivetrain is causing added load…

Checking the oil can be a pain, probably why Allison added an internal oil level sensor and controller programming to check it(has to be above a certain temp, below a certain RPM ect).

Here is one of the flow diagram from the Allison 3060/3070 troubleshooting guide.

IMG_3682.png
 

BigMontana

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Polson, MT
Thank you all, looking into everything here as the mechanics time becomes available...for now, grabbing some gear and a U-Haul and heading for home and studying for the Montana bar exam in late July.

The fun experiment shall continue slowly...
 

BigMontana

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Polson, MT
Is it possible that the thrust bearing failed and ended up blocking the flow of the transmission, and overheating it and then i only lost power when i FIRST switched directions that day because the force on the torque converter always in the same direction was holding the converter together until first change of direction?

Anyway, whomever asked about the overheating. i was measuring it from the warning lights, and the coolant temp guages...i wanted some trans temp guages and even thought about buying a Bluetooth meat thermometer for the exterior of the casings...but that idea didn't materialize before ship out day.

The truck has had heat issues from the start, but I've got handling those down pat from years of driving heavy haul in the mountains, so really at first i was just running early morning and a bit past dusk maybe, i was cutting some extra cooling into the front skid plate with an angle grinder, one notch a day...ya know cause it's useful but slow work...and as the cooling system improved each time i fixed something i'd have longer to operate each day...so the last fix on that was the intermittently leaky radiator fan clutch. she ran good for a whole day, then transmission overheating
via the warning light on the dashboard whomever asked, and i never drove it for more than 10 seconds after that light came on, I just coasted to the side of the road and broke out some books. let the engine cool for five min, restart to circulate coolant, rinse and repeat (so the engine and trans cool evenly).

Anyway that's the story of serenity the LMTV so far...to be continued.
 

BigMontana

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So wait - it overheated AND you lost "power" - what does that mean exactly?

Full story please.
The overheating was separate from the loss of power, but i'm sure it contributed in some way.

on like day 5 of a cross country trip the trans started throwing an overheat warning on the dashboard (the light) it only started in the afternoon when the reflection off the blacktop was throwing a lot of heat towards the trans...so i'd ride the truck 30 or 40 miles at about 46-47 MPH and when the light came on i'd pull to the side and do some studying, the plan being to limp it to a mechanic who is good with transmission stuff...i didn't quite get that far because as i was parking for the night (it had been at least an hour since the last overheat warning) i went to pull a "T" turn (the bigger truck version of a u-turn). and when i hit reverse it just didn't go into gear...luckily i was already on a hill so i used the truck's momentum to coast into the motel's downhill parking area. it threw code 5517, and 22(something). the "T" turn drive to reverse switch would not have been violent in any way i was already fully stopped if not drifting slightly towards reverse.

As noted by several other members, the downshift from 4 to 3 and 3 to 2 was always pretty clunky/tha-chunk-ey...so i had already been kicking it into neutral if i was going into third or lower and then hitting drive once fully stopped...the re-engage while stopped at at idle is much less harsh than the downshift...although i think some folx's hard shift problems have to do with the engine not returning to idle...or being in warm up mode...my shifts smoothed out a lot after i fixed the low idle speed.

Currently it does look like the torque converter might be spinning (it registers a speed for a minute when in gear) but nothing else, no pressure, no "tha-chunk" when you put it into gear. When you try the trans registers whatever gear you selected as having been selected (pick one, i tried them all) but then when you push the pedal down the speedo goes up for a second like you're in gear and then the trans realizes it's not in gear and removes the "you are currently in this gear" number on the selector. I checked all the wiring i could get to and cleaned the connections out with some PB blaster but the guy who had this before me must have re-done some of the wiring because all the connections were in pristine condition, and the wiring itself looks okay-ish (like it'll get replaced somewhere down the road but there's no wire shielding falling off or places where you can see copper near connectors etc. (at some point down the road i'm going to work on the electrical with my dad, a super smart electrical engineer/inventor and veitnam vet, it'll be good quality time).

I've always been a manual trans guy, most of my trucks had 18 speeds in them, a few had 36 or more gears, and if i knew of a way to trade the automatic for a regular big rig 9 speed or something similar i'd do that in a heartbeat, but i suspect if the problem is that it needs a new trans it'll just be easier to throw on a re-manufactured one, they don't look super expensive, the truck and frame all look really good, so it's all a long term investment.

I'm going to grab a small uhaul and a few things out of the truck and the folx at the shop where it is have said they will throw some boat shrink wrap over my already pretty good tarp job and we can start deciding what to do going forward but the vehicle will be okay where it is until they have the time to work on it. i already brought all my really critical things home in my first run in my 2003 jeep rubicon, so i don't "need" anything that's in the LMTV it's all just good quality stuff, like a decent collection of hardwood furniture the dumb undergrad kids throw out at the end of every school year and stuff like that.
 
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Ronmar

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Well group 55 are C3 pressure faults so something is going on with pressure or sensing that pressure.

that temp light is a programmed output generated by the controller and based off of its internal temperature sensing circuitry(sump temp sensor on the control module). The manual says it is supposed to illuminate when sump temp reaches 225F

Do you hear the engine fan kick in when coolant goes over 205F? They are louder than hell and hard to miss…

The P6 roller thrust bearing is all the way back under the rear top cover on the trans. Any parts will wind up down in the transfer case, and should find their way to the magnetic drain plug. That is how this is usually detected, parts found when transfer case oil is drained. It is not a very substantial roller thrust bearing so I don’t think it has enough parts to foul the transfer case scavenger pump Strainer. That is a secondary pumped loop that moves fluid from transfer up to main sump(probably for cooling), so not sure how it would effect overall transmission cooling. The transfer case might get warmer though…
 

Suprman

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There is a catch screen on the line from t case to scav pump. Take the line off the t case then you can unscrew the catch and see if any debris. If your t case bearing failed there will be bits of it there. It sounds like you dont have fluid pressure in the trans for some reason. Maybe bad torque converter. You can take it to an allison shop there are pressure test ports on the bottom of the solenoid pack.
 
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