MD 3060 error code 25-11

[TinTapping]

Off the top:

Really looking for informed opinions on what our chances are of the transmission, as described, making a couple hundred more miles down a not too hilly road? I know, I know, magical predictions are not mechanics...just a family that is perfectly comfortable with risks, so long as they are as informed as we can make them. We're asking for a little sounding board help from the folks that "have been there"...no one but us are on the hook here :wink1:

Secondarily, would love to see the Skoolie Hive Mind give me more things I might do to further diagnose our transmission problems?

1998 Thomas MVP
CAT 3126 a (HUEI round top with rigid supply line upgrade, engine rebuilt 99K miles ago)
Allison MD3060, automatic push button basic, R, N, 1-5 (6th locked out) and no preprogramed MODE options. The unit will read codes but does not have the fluid level sensor kit.

Brief History:

• bought bus with known hard-shift issue on 3 and 5 gears.
• bus was in shop before purchase with limp mode issue
• tech "reset fast adapt, on road test shifting smoothed. advised that valve body would need to be removed for inspection and that last MD3060 with similar issue showed sings of clutch material in valve body."
• we've driven it for 4500 miles with the hard shift issue in play knowing full well that we might be dealing with a roadside breakdown.
• no error codes have ever presented until...

Current Situation:

• pulled into a water/dump station with engine and trani at operating temp I always leaving it running on the dump but shut off engine on water fill up as the fill time can be 30-40 mins and diesel prices :wink1:
• after fill-up started engine, disengaged parking brake, selected reverse, then...
• heard a distinct whir and then felt the transmission grab, this had never happened in any gear from a stop before
• I began to reverse and had power until we start to climb the slight hill behind the transmission seemed to slip and the ECU beeped for 8 seconds and went into "do not shift" mode and locked into 1 gear; no option to select N, or D, or do any up/down shifting, as per normal limp mode
• shut down bus, restarted and the trans was open again.
• shifted into drive, whiring sound as before followed by engagement (and again, never heard this before) and then down shifted to first to keep it in one gear and was able to pull forward back to the spot where I was parked for water coming to a stop
• assessed situation and decided to pull forward and out of the next persons way (no one showed up for the three hours we were there ) and figured I'd like to park and let things cool down a bit more before trying any serious driving
• engaged drive again but didn't hear a whirring noise so accelerated as I normally would. Nothing and then the ECU beeping for 8 secs, lock out and stuck in first. At which point I tried accelerating and found I could pull forward up a slight hill and parked.
• I let the engine idle for a while and checked trans fluid level...reading overfull (nothing has been added or removed since the tech flushed in 18 months ago when I bought it) assumed it was the angle I was parked at.
• while idling checked codes and found one stored: 25-11 output speed sensor "zero"
• Briefest research showed that there is almost always a second code with this one and usually points to an electrical issue if not internal wear of the tone wheel.
• at this point a couple rangers came by (big weekend rolling in and they needed us gone) got pointed to a BLM spot three miles down the road
• Taking a gamble (no cell in the canyon had to climb out to research code...can you tell this is an adventure yet? :biggrin: ) we started up the bus, I pulled it further up the hill in front of me so I could have the slope sling me back even if R wouldn't (trans had significantly cooled and no odd noises or loss of power registered) and managed a three pointer without going into limp mode again.
• pulled onto highway keeping upper gear locked at 3rd. Though my nerves were a bit shot at that point the drive seemed fine. Pulled into the BLM spot and here we sit.

What we've done:

• Checked fluid cold and hot. Seems WAY full...but...I couldn't begin to explain why as I do check this at every fuel up though I've had times when I just couldn't be sure and it seemed over full on a couple dips but the super clean fluid is barely visible so I rely on the "lay it on a blue towel method" which is hit and miss. I will also admit that I have often trusted the "cold" read and know that the "hot" read is the better measure.
• we pulled the input sensor and the output sensor, checked for resistance: input 296 and output 295, book asks for 300 ohms...seems good.
• the turbine sensors can also be indicated though those are internal so we ran a continuity from the ECU harness and landed at 296 and figured with a 14ga 30'+ run on the wire we should only see about a 1 ohm drop so 296 seems good.
• when the output sensor was removed I checked the free rotation of the tone wheel with a small punch, smooth movement and no visible wear or material debris BUT...
• ...when I removed the output sensor about half a quart of sweet smelling ATF ran out, is that normal?
• there's not much opportunity to inspect through the input speed sensor port but the back of the torque convert is clean and no hot or unexpected odors from there

So that's where we're at.

Oh, yeah, did I mention we're 110 miles from anything like a city and parts and the like. Not that that matters a ton but my real questions are about how folks feel about our current situation in light of making that drive.

I'd aim to do it at night and will likely keep speeds below 30-35 mph, blinkers on, we're well lit all around and the highway we'll be running is low traffic at night according to the rangers I spoke with.

I'm by no means a trained mechanic but I've done everything from rebuild engines to service the F-250 and -350's we ran when I had a small construction company back in the early 2000's. So, I've done transmission swaps and clutch rebuilds and chased electrical this and that, welded, blah-blah, self taught but rarely a shade tree for credit. :wink1:

Things I'm wondering:

Can I check the torque converter without pulling the transmission? It sure felt like that feel of a manual clutch plate totally burned out and spinning.

If it is over full I know that the fluid can become aerated and that can cause hard shifting but the hard shifting is there cold too so I've discounted that before now. I read too many RV forums after we first bought the bus (more CATs in the RV world than here, yeah yeah, CATs suck and Cummins cu...) and questioned the hit and miss ATF readings and convinced myself that the dipstick was quite likely not calibrated.

Who would trust the dipstick and drain off fluid until it hits the COLD?

I'm the sort that will definitely chose to swap the transmission before going down the trillion dollar rabbit hole of guess-the-problem at $180/hr shop time. But we'll make that convo a different post if we get to that stage.

We were putting off a slow down on our travels to deal with the transmission because my dad's health is failing and we hoped to post up in Ontario for a few months. Letting us help out my mom but also do some of the mechanical that we've delayed. We're toying with ideas like parking for six months while I repair/swap out the transmission and we sort out the family stuff in Canada with a few flights here and there. Who knows, the oldest is a bit tickled by the course of events because he may just jump ship now and head off to school...he's voting for the drive down to Casper, come what may! ;-)

We'll have to move by Tuesday night, so we've got a couple days. I'll be checking in to answer questions and add info every 3-4 hours between now and then.

Looking forward to any insights. And, if this should be posted elsewhere I'll happily shift, just give me the direction. :Thanx:

All the best,
Chris

PS happy to post pics (though I can't imagine that helps with a closed transmission :wink1: but also pics of manufacturer labels.

 

[DeMac]

Error Codes?

Do you know if yours has the Allison diagnostic readouts, available by pushing the up and down buttons simultaneously?

The first is display usually shows the electronic oil level sensor info (that you don't have so...). A countdown then OK or LO or HI, then temps, engine speed....

Should have to push the up and down at the same time again to get the fault codes. No codes displays d1-- or there will be a code number after the d1

When the ongoing slip happened at 3rd / 5th, was there an increase in rpm (500rpm) before the shift?

Did you notice any bubbles (you mentioned aeration) in the fluid that came out of the sensor or on the dipstick?

 

[cadillackid]

the hardest thing about this is that in 98 and with that code its likely a WTEC-II system in that bus.. theres not a ton of info on it as WTEC-II isnt even serviceable unless you can find a shop that has the old pro-scan device.. the output speed sensor I didnt think would shift inhibit the transmission, the whirring sound almost sounds like the pump was starving for fluid as it tried to shift into gear.. if for some reason the intake sucked air then id expect a similar or whiney sound.



demac makes a great point about foamy or aerated fluid, this would indicate such a condition.. if the fluid is milky color then you can have a cooler failure where you ended up with some coolant in the mix which will cause low pressure and other issues..



im assuming you are checking your fluid with the engine running at idle speed after having engaged R then N then "D" then N again..



overly full fluid can be an issue too.. if it is truly WAY overfull the fluid can be so high that it actually bathes the rotating assembly and will foam up the fluid so much that the pressure drops on the driveline.. I expect to see this after it being driven and things work fine after it has sat and the fluid comes back to a normal state.



-Christopher

 

[TinTapping]

Do you know if yours has the Allison diagnostic readouts, available by pushing the up and down buttons simultaneously?

Yup, sure does...WTECH 2, I believe. We don't have the PC tool to plug in but the double arrow push gives fault codes only, no ATF level tool.

The ECU stored one code: 25 - 11 which is output sensor "zero"

When the ongoing slip happened at 3rd / 5th, was there an increase in rpm (500rpm) before the shift?

Actually, the ongoing 3rd/5th is a clunk. Very much like a a bad manual shift where you drop the clutch on a too-low rpm engine. But no, there is no rev up on shift. the engine stays smooth as it drops down in RPMs with the gear shift. Makes me wonder if it's not the toque convertor? Plus a fluid level issue? Combined symptoms.

Did you notice any bubbles (you mentioned aeration) in the fluid that came out of the sensor or on the dipstick?

No. Fluid is clear and smooth. At temp it's thin enough that its difficult to read the upper meniscus mark of the ATF. But there's no burn smell and the ATF that drained out of the output senor port looked like new.

Digging around in diesel forums it seems that the fluid level may well be the culprit. I'm not too keen on draining fluid where I'm at given that I don't have ATF on hand if something goes sideways...I suppose I could rig the hand pump I have with a small diameter tube and syphon off the dip tube.

I plan on planning on heating up the engine and transmission today so that I can do a slow walk through of fluid level and see if a brake on in drive warm up throws any codes.

 

[TinTapping]

the hardest thing about this is that in 98 and with that code its likely a WTEC-II system in that bus.. theres not a ton of info on it as WTEC-II isnt even serviceable unless you can find a shop that has the old pro-scan device.. the output speed sensor I didnt think would shift inhibit the transmission, the whirring sound almost sounds like the pump was starving for fluid as it tried to shift into gear.. if for some reason the intake sucked air then id expect a similar or whiney sound.

Interesting, hadn't thought of a starved pump...but yeah, the whir is building noise...hmmm...

demac makes a great point about foamy or aerated fluid, this would indicate such a condition.. if the fluid is milky color then you can have a cooler failure where you ended up with some coolant in the mix which will cause low pressure and other issues..

And that confuses me. While I might not know how to read a dip stick :wink1: I've been keeping an eye on it because of the hard shifting issue. I've never explicitly looked for aeration, or a coolant intrusion, but the clarity of the fluid on the stick has been consistent...

im assuming you are checking your fluid with the engine running at idle speed after having engaged R then N then "D" then N again..



overly full fluid can be an issue too.. if it is truly WAY overfull the fluid can be so high that it actually bathes the rotating assembly and will foam up the fluid so much that the pressure drops on the driveline.. I expect to see this after it being driven and things work fine after it has sat and the fluid comes back to a normal state.

-Christopher

...I'm thinking that I'm gonna need to repeat the circumstance of the Limp Mode on Thursday. I've reset codes so I can be looking for any new pops and then inspect ATF specifically for signs of aeration. That means a little midnight run to Casper is in the future. :biggrin:

Any thoughts on high fluid level being a cause of hard shifting? I can stare at the diagrams of the internals of the MD3060 for days but just don't have a deep conceptual map what does what when. :wink1:

Thanks for your help on this! :Thanx:

-Chris

 

[magnakansas]

Tin tapping

I think you can have full fluid AND no fluid to the pump. OR fluid with air and result is no pressure….


If the in pan filter fell out, or if the oring for the in pan filter has a problem, you could be sucking up air and fluid = foamy stuff.

William

 

[cadillackid]

I think you can have full fluid AND no fluid to the pump. OR fluid with air and result is no pressure….


If the in pan filter fell out, or if the oring for the in pan filter has a problem, you could be sucking up air and fluid = foamy stuff.

William

true that.. on this trans though the filters are pretty secure, but doesnt mean a bolt didnt come loose in the pan and either sucks air at the valve body plate or from a filter.. someone at one point on this forum had their valve body bolts back out on their 3060.. that was a few years ago..


only way to truly tell is get a pressure gauge on the main pressure tap and see if main line pressure is lost in a variety of scenrios.. (tilting, turning, stopping, accelerating)..


tintapping - an allison is a clutch type trans.. so from reading the other parts of this thread.. and increase of 500 RPM and then a clunk shift direclty together is called a Flare... if the transmission cant succesfully mitigate severe flares it will limp and stay in what it calls its Inhibit Gear (every TCM can be programmed with inhibit mode gear.. usually 3 on a 5 or 6 speed).. the transmission can also determine that its condition is bad enough to lock itself down into a SINGLE range of wherever it currently is (if below inhibit)...


another condition that results in a pronounced "snap" back or clunk feeling is a Bind.. Binds are especially dangerous and if the trans thinks it incurs one and cant get out of it or mitigate it next time, you get limped. Bind occurs when the offgoing clutch doesnt get outta the way quick enough for the oncoming clutch, so you bind up as the oncoming clutch is either trying to spin-up a drum that was previously held stopped by the offgoing clutch or it is trying to stop a drum that was previously held engaged by the offgoing clutch.. the result is at a minimum wearing the friction discs down pretyy quickly.. ..and the worst is where to break metal parts.. usually strip out a sprague or snap an input shaft... either way the result is your vehicle goes on a hook...





timing is everything in these older rigs.. ther 3000 series shift schedule is such that pretty much every shift requires one clutch to disengage and then another to engage.. a flare is where the offgoing clutch comes off and the oncoming clutch is slow to come on. the TCM program by using the speed sensors within the transmission knows when flares occur and tries to limit them..



if you have a faulty or erratic speed sensor it can very much affect shifting as the transmission has to guess or use a preprogrammed algorithm to make the shifts..



I dont know much about WTEC-II stuff as i have never had the ProScan to watch one in action.. but from what ive read it has adaptive shifting..



as a transmission wears the pressures and timing of the shifts changes, as the filters clog up with dirt, the potential for line pressure changes is there too.. change the filters and fluid and now the adapts can be all wrong (thus why im sure you've read about "resetting the adapts" after any service to an electronic allison.. this is done so it can re-learn how to make proper shifts...



later Gen 3 and all Gen 4 / 5 TCMs have the ability for "fast adapt" which is where you do a reset and enable fast learn.. you drive your vehucle foot to the floor, gears 1-4 then stop.. then do it again 4 times and it learns how to make clean shifts at full throttle..


im sure you have seen this.. a WTEC-II troubleshooting manual..


https://krutzaspreading.com/wp-content/uploads/2018/07/Allison-WTEC-2-Troubleshooting-Manual.pdf


as for your erratic sensor.. the best advice I have is to get a known good sensor.. make sure it seats fully in (that there isnt a leftover O-ring from a previous sensor).. and that the wiring connections on the Connector and the TCM connector are Clean... if your tone ring is full of metal that will cause erratic readings too. usually its the sensor that will collect the metal but in a failing trans ive seen bits of dirt get built up in the edges of the toine ring teeth and cause wierd readings..



without the ability to scan it on a PC and watch the sensor data, this gets tougher..

 

[TinTapping]

Excellent...well, not excellent for the bus...but it's this conceptual aspect of what could be happening internally that I can't run in my mind because I've just never had the chance to learn the insides of a transmission. Much appreciated!

 

[TinTapping]

:Thanx:

Reading as much as I have the past three days, I was going a bit bonkers--feeling like I had no chance to synthesize the info and have any clarity. This post really helped tie the knot on a lot of my confusion. I hugely appreciate everyone's time.

true that.. on this trans though the filters are pretty secure, but doesnt mean a bolt didnt come loose in the pan and either sucks air at the valve body plate or from a filter.. someone at one point on this forum had their valve body bolts back out on their 3060.. that was a few years ago..

only way to truly tell is get a pressure gauge on the main pressure tap and see if main line pressure is lost in a variety of scenrios.. (tilting, turning, stopping, accelerating)..

Hmmm...I'm guessing I'll need something other than the mechanical engine pressure gauge I have on hand...something that will store readings over the test drive. Perhaps ratchet strapping a couple boys to the frame; one calls off the gauge readings, the second scratches down notes! :biggrin:

tintapping - an allison is a clutch type trans.. so from reading the other parts of this thread.. and increase of 500 RPM and then a clunk shift direclty together is called a Flare... if the transmission cant succesfully mitigate severe flares it will limp and stay in what it calls its Inhibit Gear (every TCM can be programmed with inhibit mode gear.. usually 3 on a 5 or 6 speed).. the transmission can also determine that its condition is bad enough to lock itself down into a SINGLE range of wherever it currently is (if below inhibit)...

When a flare, or a bind, happen would one not expect a code to pop that said essentially that? Or is it the sort of thing where a mechanic would see a code like 25-11 output speed "zero" and know that a flare or bind was a situation to check closer for?

another condition that results in a pronounced "snap" back or clunk feeling is a Bind.. Binds are especially dangerous and if the trans thinks it incurs one and cant get out of it or mitigate it next time, you get limped. Bind occurs when the offgoing clutch doesnt get outta the way quick enough for the oncoming clutch, so you bind up as the oncoming clutch is either trying to spin-up a drum that was previously held stopped by the offgoing clutch or it is trying to stop a drum that was previously held engaged by the offgoing clutch.. the result is at a minimum wearing the friction discs down pretyy quickly.. ..and the worst is where to break metal parts.. usually strip out a sprague or snap an input shaft... either way the result is your vehicle goes on a hook...

timing is everything in these older rigs.. ther 3000 series shift schedule is such that pretty much every shift requires one clutch to disengage and then another to engage.. a flare is where the offgoing clutch comes off and the oncoming clutch is slow to come on. the TCM program by using the speed sensors within the transmission knows when flares occur and tries to limit them..

if you have a faulty or erratic speed sensor it can very much affect shifting as the transmission has to guess or use a preprogrammed algorithm to make the shifts..

This is really helpful. You paint a really clear picture that is starting to fill in the gaps between what I've experienced in operating the vehicle and what little I comprehend about the workings of the drive train.

I dont know much about WTEC-II stuff as i have never had the ProScan to watch one in action.. but from what ive read it has adaptive shifting..

as a transmission wears the pressures and timing of the shifts changes, as the filters clog up with dirt, the potential for line pressure changes is there too.. change the filters and fluid and now the adapts can be all wrong (thus why im sure you've read about "resetting the adapts" after any service to an electronic allison.. this is done so it can re-learn how to make proper shifts...

Makes sense, and yes, that's what most folks on diesel forms recommend is first having a tech run a fast adapt reset as you describe next.

later Gen 3 and all Gen 4 / 5 TCMs have the ability for "fast adapt" which is where you do a reset and enable fast learn.. you drive your vehucle foot to the floor, gears 1-4 then stop.. then do it again 4 times and it learns how to make clean shifts at full throttle..


im sure you have seen this.. a WTEC-II troubleshooting manual..


https://krutzaspreading.com/wp-content/uploads/2018/07/Allison-WTEC-2-Troubleshooting-Manual.pdf

It's why my eyes are currently crossed!

as for your erratic sensor.. the best advice I have is to get a known good sensor.. make sure it seats fully in (that there isnt a leftover O-ring from a previous sensor).. and that the wiring connections on the Connector and the TCM connector are Clean... if your tone ring is full of metal that will cause erratic readings too. usually its the sensor that will collect the metal but in a failing trans ive seen bits of dirt get built up in the edges of the toine ring teeth and cause wierd readings..

Tone ring and surrounding area appear free of any debris, metal or otherwise. And the tone ring spins free and smooth. But yeah, I've had several instances on other vehicles where a sensor passed a multimeter test but problem persisted until I swapped out for a new one. Now that the long weekend is past we'll be able to start tracking down such parts.

without the ability to scan it on a PC and watch the sensor data, this gets tougher..

And that's a question I was gonna start looking into...what are the odds of getting my hands on a scan tool myself...this is more of a covered wagon adventure than a bought and paid for vacation that we've undertaken as a family after all...gotta show these boys how to dig yourself out of a hole before they set off on their own. :biggrin:

I'm not about to tool up to be a trans tech, as fun as that would be to watch , but if a scan tool could tell me enough that I could either see smaller repairs I could manage to pull off while the transmission is in place OR lead me to feel that a refurb MD3060 is the better bet...then I'd rather have something I can sell (scanner tool) than a massive Chasing Problems Tech bill from a shop...and still need to put in a new-to-me unit. I suppose if I was going to attempt my own transmission swap (maybe not a great idea in an RV Park :wink1 I'd need a tool that was capable of flashing to "reset adapts" as you mention?

Something like this Gameboy couldn't do that I suppose: pick your flavor 3000/4000 series or WTEC

Either way this roles, the family is leaning toward trying to move the bus this evening and limp (if needs be...I'll post a separate update of my operating temp test yesterday) to an RV Park where we'll go month-to-month while we sort this out. The two oldest have been browsing the U of Wyoming college catalogs and grinning away at the thought of jumping ship!

Thanks again for all the effort in looking at our situation.

 

[cadillackid]

Excellent...well, not excellent for the bus...but it's this conceptual aspect of what could be happening internally that I can't run in my mind because I've just never had the chance to learn the insides of a transmission. Much appreciated!

if you ever want to learn and see the insides of a transmission you can watch a youtube channel called precision transmission.. these guys are a tranny shop.. and they record and show the tear-down videos of broken transmissions.. they are usually GM , dodge, ford rear drive stuff.. while an allison is somewhat different inside.. you can see and learn some of the concepts like how clutches engage drums and fluid passages can move clutch pistons, etc...


one of the issues with diagnosing transmissions is the fact many things can cause a symptom.. or a code...



your code.. could be a wiring issue,, or the sensor, or the alignment of the tone ring and sensor..



maybe a bearing is going causing end play in the shaft.. or what if one of the 2 first gear clutches fails to engage.. the TCM sees throttle, the TCM sees the input shaft spinning, the TCM doesnt see the output shaft spinning.. (but may have seen the intermediate shaft spinning if the C1 clutch pulled in)



so BAM! throws a code of a zero output sensor speed... why? because in the computer's mind it shifted into gear and shouldve been moving but wasnt.. or thinks it wasnt..



so you can see how it becomes an involved and methodical procedure to try and figure out exactly whats wrong..

 

[TinTapping]

Precision Transmission shall play on the dinette TV until further notice!

And yes, well described. This is exactly what I was seeing as the landscape of troubleshooting such a complex piece of engineering; there's a need for a deep understanding of the mechanism in order to rapidly run scenarios based on murky points of data. Super respect for those, like yourself, who can sort such things.