- 6,842
- 654
- 113
- Location
- Stratford/Connecticut
The rectangular diag port is J1708 it is older but not uncommon. There are readers of various caliber available online. I have to load up the software to my laptop and see if I can communicate with it.
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Diagnostics port LMTV
- Thread starter tennmogger
- Start date
- 1,576
- 527
- 113
- Location
- Greenback, TN
Some of the issues with my LMTV keep changing. Maybe this info will be useful to others as they learn their FMTV.
The speedometer that began working last trip is not working right again (reads a little over half what it should). The fix/fail is abrupt and seems to change when the transmission shifts. This still indicates a connection or sensor problem(?) but has yet to be found.
The fan clutch has fixed itself. Before, the fan would not turn by hand with engine off. Now the fan will turn and I can feel the viscous coupling resisting. Apparently the clutch was stuck and the fan ran all the time. The fan feels right now!
On a drive yesterday the temps climbed on the gauge to about 210 and I heard the fan come on! Whooppee! Yeah, no missing it when it comes on! It only stayed on half a minute but the temp dropped and fan turned off. As I described before, on one drive the engine temp warning light came on at about 215 but the fan never turned on. Now the sequence is as it should be, heating leads to fan on, engine cools, and no temp warning. Some small things are fixing themselves.
The vibration in the engine area still evades me. However, my cousin rode with me and listened from the passenger side. He suggested the vibs are from a contact point somewhere. As long as the engine is torqued, as when pulling, there is no contact, but when fueling rate backs off maybe the engine unwinds a little and makes contact with something.
To be honest, I was panicked a little thinking I was hearing the dreaded driveline problem experienced with earlier FMTV's. However, the driver-sensed characteristics of that failure are unknown to me. My truck does have the "D" stamped on the ID tag so has had the upgrades. There's a thread on SS about this upgrade but I can't find it.
Some searching found some information worth a read: http://www.dote.osd.mil/pub/reports/FY1999/army/99fmtv.html
Monitoring temperatures of the various components of the truck showed up a warmer pinion on the front driveshaft. The pinion was running 15 to 20 deg hotter than the diff itself. This morning I drained the diff to check for any wear products and only found maybe 1/3 ltsp of very fine magnetic mush on the magnet. No chunks, slivers or solids, so I feel ok about the front diff. Just in case, I treated it to Amsoil Severe Gear synthetic lube and will check temps again. (That made no difference to the vibration.)
Bob
The speedometer that began working last trip is not working right again (reads a little over half what it should). The fix/fail is abrupt and seems to change when the transmission shifts. This still indicates a connection or sensor problem(?) but has yet to be found.
The fan clutch has fixed itself. Before, the fan would not turn by hand with engine off. Now the fan will turn and I can feel the viscous coupling resisting. Apparently the clutch was stuck and the fan ran all the time. The fan feels right now!
On a drive yesterday the temps climbed on the gauge to about 210 and I heard the fan come on! Whooppee! Yeah, no missing it when it comes on! It only stayed on half a minute but the temp dropped and fan turned off. As I described before, on one drive the engine temp warning light came on at about 215 but the fan never turned on. Now the sequence is as it should be, heating leads to fan on, engine cools, and no temp warning. Some small things are fixing themselves.
The vibration in the engine area still evades me. However, my cousin rode with me and listened from the passenger side. He suggested the vibs are from a contact point somewhere. As long as the engine is torqued, as when pulling, there is no contact, but when fueling rate backs off maybe the engine unwinds a little and makes contact with something.
To be honest, I was panicked a little thinking I was hearing the dreaded driveline problem experienced with earlier FMTV's. However, the driver-sensed characteristics of that failure are unknown to me. My truck does have the "D" stamped on the ID tag so has had the upgrades. There's a thread on SS about this upgrade but I can't find it.
Some searching found some information worth a read: http://www.dote.osd.mil/pub/reports/FY1999/army/99fmtv.html
Monitoring temperatures of the various components of the truck showed up a warmer pinion on the front driveshaft. The pinion was running 15 to 20 deg hotter than the diff itself. This morning I drained the diff to check for any wear products and only found maybe 1/3 ltsp of very fine magnetic mush on the magnet. No chunks, slivers or solids, so I feel ok about the front diff. Just in case, I treated it to Amsoil Severe Gear synthetic lube and will check temps again. (That made no difference to the vibration.)
Bob
- 6,842
- 654
- 113
- Location
- Stratford/Connecticut
Speedo issues with trans shifting issues is more than likely the speed sensor at the bottom of the trans. Not an expensive fix. I hooked up the rda v3 and am able to see it in several programs connected to the truck but can't get any data as of yet. I have the Dana ctis program that says it can't communicate with the ctis control. The ice diagnostics want me to use the big round connector and the interface box which I left at work. All of the diagnostic programs that run thru the rda interface are lmtv a1. I will have to play with it some more. Maybe the rectangular connector is only for the transmission.
- 6,842
- 654
- 113
- Location
- Stratford/Connecticut
If you are having issues and want to bypass a relay or some issue where a relay won't engage to start the truck or operate a feature you can make up a small wire with a spade connector on each end and use it to bypass the relay. And here's a pic of the vim box inside. 6 bosch style relays and 2 fuses. It's located behind the passenger dash kick panel.
- 1,576
- 527
- 113
- Location
- Greenback, TN
This is a follow up on my speedo issue, and engine temp issue.
I mentioned before that the speedo was 'off' by the ratio 5/8, same ratio as km to miles. Problem was, the dial on the speedometer (black in mph) was showing 25 mph when gps speed are really 40 mph. Like the computation for kph and mph was backwards. Well, I noticed this weekend that there is another scale on the speedo, in very light pink (faded?) that is supposed to be the reading in kph. Guess what, if I read the pink scale it is right on the nose for mph and matches the gps! Ok, who can explain that
Temperature sensor issues, these seem common. My fan switch had started working fine a few weeks ago. The fan will switch on at 200 deg on the gauge and drops the engine temp almost immediately. The other separate (I think) system detects about 210 deg and turns on the "stop" and overtemp symbol on the display. That overtemp indicator works fine on mine.
Problem is that occasionally the fan switch does not work and lets the truck overheat. Yesterday I caught it in overtemp, 210 deg, and as quickly as I could get the cab up, measured the resistance of the overtemp switch, reading about 2000 Ohms. Apparently this switch is supposed to close when the temp goes too high.
I'm looking for a replacement. Has anyone found a part number available from a local source? I am sure someone posted a number but my searching has failed.
FYI, found this nice list of part numbers for the Oshkosh version, if anyone needs it: http://oshkoshdefense.com/wp-content/uploads/2013/11/Oshkosh-Corporation-Price-List-March-2013.pdf
thanks,
Bob
WB4ETT
Here's my truck from last weekend:
I mentioned before that the speedo was 'off' by the ratio 5/8, same ratio as km to miles. Problem was, the dial on the speedometer (black in mph) was showing 25 mph when gps speed are really 40 mph. Like the computation for kph and mph was backwards. Well, I noticed this weekend that there is another scale on the speedo, in very light pink (faded?) that is supposed to be the reading in kph. Guess what, if I read the pink scale it is right on the nose for mph and matches the gps! Ok, who can explain that
Temperature sensor issues, these seem common. My fan switch had started working fine a few weeks ago. The fan will switch on at 200 deg on the gauge and drops the engine temp almost immediately. The other separate (I think) system detects about 210 deg and turns on the "stop" and overtemp symbol on the display. That overtemp indicator works fine on mine.
Problem is that occasionally the fan switch does not work and lets the truck overheat. Yesterday I caught it in overtemp, 210 deg, and as quickly as I could get the cab up, measured the resistance of the overtemp switch, reading about 2000 Ohms. Apparently this switch is supposed to close when the temp goes too high.
I'm looking for a replacement. Has anyone found a part number available from a local source? I am sure someone posted a number but my searching has failed.
FYI, found this nice list of part numbers for the Oshkosh version, if anyone needs it: http://oshkoshdefense.com/wp-content/uploads/2013/11/Oshkosh-Corporation-Price-List-March-2013.pdf
thanks,
Bob
WB4ETT
Here's my truck from last weekend:
Attachments
wyocommo
Member
- 52
- 6
- 8
- Location
- Casper, WY
You might carefully check the air solenoid that controls the fan. It dumps air to engage the fan. Mine appeared to work fine on the bench but when put under load in the truck it failed to vent the air between it and the fan clutch.
It was very intermittent in the beginning. There was no predicting how it would react.
The solenoid is located behind the passenger kick panel just inside the door. With the kick panel off you can hear the distinctive air dump sound when the solenoid engages. The solenoid is normally engaged to keep the fan clutch off and disengages when temp is high. This arrangement makes it fail safe should a wire break or such.
Seems as though it has been a problem for a lot of LMTV owners
It was very intermittent in the beginning. There was no predicting how it would react.
The solenoid is located behind the passenger kick panel just inside the door. With the kick panel off you can hear the distinctive air dump sound when the solenoid engages. The solenoid is normally engaged to keep the fan clutch off and disengages when temp is high. This arrangement makes it fail safe should a wire break or such.
Seems as though it has been a problem for a lot of LMTV owners
- 1,576
- 527
- 113
- Location
- Greenback, TN
Thanks. I will check that air solenoid in the morning. When the fan works I do hear that air get dumped, and when the fan does not come on there is no air dump. I had assumed the problem was electrical.
That solenoid is electric, right? Can I put a meter on it to watch for electrical activation to be followed by air dump, or no air dump? That would prove if the temp switch is bad or not.
Bob
Overdrive
Active member
- 411
- 89
- 28
- Location
- Wentzville, Missouri
Is this the correct solenoid behind the kick panel?
PARKER 8204 0459-45 24V-DC SOLENOID VALVE D445718
I got it off another thread and have the valve as a "carry a spare in the toolbox" item.
PARKER 8204 0459-45 24V-DC SOLENOID VALVE D445718
I got it off another thread and have the valve as a "carry a spare in the toolbox" item.
tburk49760
Member
- 398
- 10
- 18
- Location
- spokane washington
My solenoid was behaving similarly. Disassembled it and used 3in1 oil. Seems great for the past 1k miles. When diagnosing it, if I tapped it after the engine was above 205, it would release and start the fan... Once... Til I oiled it.
dalej
Member
- 94
- 5
- 8
- Location
- Blue Hill Nebraska
I had talked to a Allison Tech here in Nebraska today. He sounded like I could take off the transmission ECM or CIM or some little box that has the transmission program in it. He said it's not the one behind the passenger knee panel, that's a relay and something else box. He said to look for a box with three bolts holding it on and it should have 2 or 3 wires going to it. I really can't find anything like that on my truck.
Do you guys know of any Allison box that he might be talking about? I really didn't want to tear into the dash looking for something that might not be there or even exist.
Do you guys know of any Allison box that he might be talking about? I really didn't want to tear into the dash looking for something that might not be there or even exist.
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- 6,842
- 654
- 113
- Location
- Stratford/Connecticut
The ecu is behind the keypad. There is a port to the right of the steering wheel. Its an older interface used to access it the Allison dealer should still have it though. There is a bunch of stuff that can be adjusted. Dont take the ecu out unless you really need to.
dalej
Member
- 94
- 5
- 8
- Location
- Blue Hill Nebraska
Thanks, he sounded like it was something I could send in and he could reprogram it. I'll call back and see if he and I were on the same page.
- 6,842
- 654
- 113
- Location
- Stratford/Connecticut
Another member had their shifts reprogrammed by the Allison dealer. I have the interface but not the Allison software to do it. Still working on that it costs big bucks for the software.
- 1,576
- 527
- 113
- Location
- Greenback, TN
After another failure of the air solenoid to turn on the fan, I replaced the solenoid. Another FMTV owner (thanks Fastsailor) had posted a replacement number for that solenoid:
PARKER 8204 0459-45 24V-DC SOLENOID VALVE D445718
Got one off ebay. It swapped in just fine, only needing to have a pair of female 1/4 flat-blade terminals added.
The original Burkert (Buerkert) MKEN 301-303 solenoid uses a soft center in the slug of the solenoid to act as two seals, one on each end. Two problems were found: first, the normally closed valve was sticking closed because the soft slug material had extruded into the valve seat, and second, the rear seal was leaking, draining the truck air ever-so-slowly. Good riddance on that troublemaker. The Parker solenoid is only about $20.
Bob
PARKER 8204 0459-45 24V-DC SOLENOID VALVE D445718
Got one off ebay. It swapped in just fine, only needing to have a pair of female 1/4 flat-blade terminals added.
The original Burkert (Buerkert) MKEN 301-303 solenoid uses a soft center in the slug of the solenoid to act as two seals, one on each end. Two problems were found: first, the normally closed valve was sticking closed because the soft slug material had extruded into the valve seat, and second, the rear seal was leaking, draining the truck air ever-so-slowly. Good riddance on that troublemaker. The Parker solenoid is only about $20.
Bob
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dalej
Member
- 94
- 5
- 8
- Location
- Blue Hill Nebraska
Well, I removed the ECM unit part way so I could see the label on the side. It shows the CIN numbers that Allison needs to see what program is in the unit and see what can be done to reprogram it. He first said to just reset the shift pattern and see if it helps but he thought it wouldn't.
Dis-assembly:
There is supposed to be four bolts holding the ECM unit in the bracket but mine had only two. You have to remove the nut clip from the bracket in order for the unit to slide out. They are marked in blue.
I took the four dash bolts out to let the bracket slide back to show the label. They are marked in yellow.
The label is on the port side so you can read your CIN numbers pretty easy.
I then put it back together until I hear back from Allison about their recommendation.
Dis-assembly:
There is supposed to be four bolts holding the ECM unit in the bracket but mine had only two. You have to remove the nut clip from the bracket in order for the unit to slide out. They are marked in blue.
I took the four dash bolts out to let the bracket slide back to show the label. They are marked in yellow.
The label is on the port side so you can read your CIN numbers pretty easy.
I then put it back together until I hear back from Allison about their recommendation.
- 1,576
- 527
- 113
- Location
- Greenback, TN
Double posting, deleted this one....because i don't know how to remove a post 
Bob
Bob
Last edited:
- 1,576
- 527
- 113
- Location
- Greenback, TN
DaleJ, what is the problem you are trying to solve? Sorry I am kinda lost on the nature of your failure. Poor shifting can be due to some minor problems not really transmission dependent, like engine idle too high (covered elsewhere). It's also possible to adjust the throttle position sensor linkage so the trans shifts a little earlier. There's a thread covering some of those issues:
http://www.steelsoldiers.com/archive/index.php/t-143733.html
Bob
http://www.steelsoldiers.com/archive/index.php/t-143733.html
Bob
dalej
Member
- 94
- 5
- 8
- Location
- Blue Hill Nebraska
I don't have a problem with my truck, I just like know all the parameters of this truck. Just like all my vehicles, I just enjoy the engineering and like to understand them. I might not ever do any adjustments on the transmission programming but if I wanted to, I would know what's available and how to do it.
- 6,842
- 654
- 113
- Location
- Stratford/Connecticut
Lots of shift adjustments. Even though it's an old system most of the parameters can be reprogrammed.
dalej
Member
- 94
- 5
- 8
- Location
- Blue Hill Nebraska
I took my truck to Inland Truck Parts Company in Lincoln NE to have my Allison reset. It cost $45 to have them hook up to it and check it out and reset the shift memory. I really didn't feel any difference driving home (around 100 miles) then driving up there. I'm glad I had them do it because now I know it is how Allison programmed the transmission to shift.