CTIS Overspeed indicator flashes at 30 mph

[coachgeo]

Torque is split 30 front 70 rear in normal driving mode. The front and rear driveshaft speed can vary slightly with cornering and such. In mode the center diff is locked, splitting power 50/50 and forcing both driveshafts to turn at the same speed.

thanks for clarity.... Understood that concept but had not yet heard in the FMTV community calling a portion of the Tcase a Diff. Have heard it termed that way in over the years about other AWD systems though. Again thanks for the clarity.

So do I understand it right that there are clutch rings (7 of them I think) that send power to the front half of the Tcase. They are used essentially to rob power from the gear driven rear output of the Tcase. This robbed power is what spins the front output of the Tcase. Given that; it would make sense that all the clutches are put into a "lock" together environment of some sort in the Off Road mode resulting in the 50/50. hmm... would potentially explain why there was not unusual clutch damage seen in my trucks Tcase when it was worked on even though it had been driven a bit (more like a lot) on the front axle only. Must be that this lock together of the clutches ends up to be pretty **** solid. An Allison Corp. Tech; in conversation with them, said they never tested the FWD only scenario tis why they don't reccomend FWD even temporarily.


But.......... don't want to hijack this fellows thread any further so feel free to email, PM or point myself and others to links or keywords to search by to find more info on how the FMTV's AWD Tcase works.

Again thanks.

Good luck Joshua on getting this upgraded MTV back on the road (and off road ) Also much much thanx for your service to our country

 

[JoshuaGrooms83]

Do you have the Y cable to access the CTIS controller? You can download the software from Dana. If you have the Y cable, whats the part number or NSN I have been trying to get my hands on one of those for a while. I dont believe the CTIS controller can be accessed any other way.

No I don't have the Y cable. hat would make things a lot easier on both our ends. But the Dearborn Protocol III adaptor I have is suppose to be able to hook into the J1708 databus and control things that way, similar to an OBDII kind of deal.
According to the Dana tech guys, I can use the Dana Diagnostics software through the Dearborn Adaptor to change the Overspeed parameters by changing the pulse readings from the output sender. My problem now is that my software is old, and I have to update it off the government network because our diagnostic computers aren't network approved... go figure.

 

[JoshuaGrooms83]

thanks for clarity.... Understood that concept but had not yet heard in the FMTV community calling a portion of the Tcase a Diff. Have heard it termed that way in over the years about other AWD systems though. Again thanks for the clarity.

So do I understand it right that there are clutch rings (7 of them I think) that send power to the front half of the Tcase. They are used essentially to rob power from the gear driven rear output of the Tcase. This robbed power is what spins the front output of the Tcase. Given that; it would make sense that all the clutches are put into a "lock" together environment of some sort in the Off Road mode resulting in the 50/50. hmm... would potentially explain why there was not unusual clutch damage seen in my trucks Tcase when it was worked on even though it had been driven a bit (more like a lot) on the front axle only. Must be that this lock together of the clutches ends up to be pretty **** solid. An Allison Corp. Tech; in conversation with them, said they never tested the FWD only scenario tis why they don't reccomend FWD even temporarily.


But.......... don't want to hijack this fellows thread any further so feel free to email, PM or point myself and others to links or keywords to search by to find more info on how the FMTV's AWD Tcase works.

Again thanks.

Good luck Joshua on getting this upgraded MTV back on the road (and off road ) Also much much thanx for your service to our country

I have to say, ive only changed out one transfer case in the larger trucks and it was out of a PLS. When I have some time ill have to post that up with pictures. that was fun. instead of dropping the Tcase, we lifted the PLS up and then Pallet jacked it out from under it. It was pretty cool. Way easier then the books method of dropping it and then laying it on its side... all 1500lbs of it. No big deal right? lol

Yeah im trying to get this thing back on the road trust me. Its the bane of my existence right now. Good thing I don't work flat rate or I would be broke lol

On a positive note, another LMTV I swapped the motor out of got picked up by the unit today and it drove out after being towed in One down, two more to go! lol we got another in last week probably needing a motor as well. its al the old 1083s and 1078s S&S or BAE trucks with the older CAT motors. That keep either breaking oil lines or cracking the gear covers by the air compressor. Keep an eye on that so you don't wind up blowing a motor. Our engines cost us about $40G to replace... and there arn't even new. The last one I replaced was crated and preserved back in 2008.

and no need to thank me, its an honor to serve and to continue to serving. But thank you

 

[Suprman]

It is my understanding that on first gen trucks you can only access the ctis controller with the Y cable. Maybe on the newer A1 C7 trucks with the computer bus you can get in thru the main diag port. The port on the right of the column is trans only.

 

[coachgeo]

...
On a positive note, another LMTV I swapped the motor out of got picked up by the unit today and it drove out after being towed in One down, two more to go! lol we got another in last week probably needing a motor as well. its al the old 1083s and 1078s S&S or BAE trucks with the older CAT motors. That keep either breaking oil lines or cracking the gear covers by the air compressor. Keep an eye on that so you don't wind up blowing a motor. Our engines cost us about $40G to replace... and there arn't even new. The last one I replaced was crated and preserved back in 2008.

and no need to thank me, its an honor to serve and to continue to serving. But thank you

thank you for throwing that info out there. started a new thread on this topic so not to hijack yours. When you find the time if you could elaborate more over there about these common failure points everyone would certainly appreciate it. Below is link

http://www.steelsoldiers.com/showthread.php?156946-Where-do-the-3116-s-fail

 

[Suprman]

Been thinking. On the alternator regulator are 2 terminals. One is the 24 volt excite/regulation lead. It divides the 24volt to regulate the 12 volt output. The second lead is an AC (yup alternating current) output generated by the alternator. Intended to drive a tach or other small AC accessory. In the newer A1 C7 trucks I believe it connects to the advanced polarity protective box under the spare tire. If you changed the motor and changed the alt maybe this is coming into play somewhere. It's connected to something on the first gen trucks I could never figure out what and I usually advise people to disconnect it when having alternator related issues. The wire to the 24 volt regulation is a common failure on older trucks.

 

[JoshuaGrooms83]

Im not sure yet. still trying to get stuff figured out. Im thinking you may be right though. Although I can "see" that I have a CTIS module connected, I can not actually perform any tests on the Databus software that is CTIS related. Im wondering if I might have to go through the STA/ICE port instead of the data port to access it. im gonna attempt that today. Wish me luck! lol

 

[Suprman]

You need the Y cable to access that ctis control. The Y cable should be part of the msd V3 connection kit.

 

[Zeke]

CTIS module is missing from my 1083. Also lookin for the parts manual for the same. Anyone have suggestions?

 

[spankybear]

Did you ever find a solution?

 

[Zeke]

Did you ever find a solution?

No I have not. We plugged it up and bypassed it. I would rather put it back to original......

 

[Ronmar]

No I have not. We plugged it up and bypassed it. I would rather put it back to original......

Go to fleabay and search this:

Used? Eaton Air Regulator Valve for CTIS in FMTV LMTV MTV M1078 ????

or this:
Used Spicer CTIS Air Regulating Valve, 19207SOCN12418057 for FMTV LMTV MTV M1078

the second one has the relief valve(used as a regulator in deflate mode).

 

[snowtrac nome]

if it was an electronic engine you replaced it should have came with a new ecm bolted into the side maybe its not programmed right for your ctis. im in teh process of replacing a cat c-7 right now it came with a new ecm on it.

 

[spankybear]

No I have not. We plugged it up and bypassed it. I would rather put it back to original......

I was asking about the orignal issue with the CTIS overspeed light flashing. I bought a replacement CTIS ECU and this one too flashes the overspeed light. I was wondering if he found the issue. Other than the flashing overspeed light the replacement ECU works fine.

 

[coachgeo]

I was asking about the orignal issue with the CTIS overspeed light flashing. I bought a replacement CTIS ECU and this one too flashes the overspeed light. I was wondering if he found the issue. Other than the flashing overspeed light the replacement ECU works fine.

seem to recall a mention of RPM sensor wire issues (or sensor itself) . The one mounted on the bell housing... giving wrong or erratic signal. Maybe dig thru wire diagram and trace back to see for sure what the ctis ecu is using to determine speed to verify it is the one on bell housing or not.

Hopefully someone will chime in with better details.

 

[spankybear]

seem to recall a mention of RPM sensor wire issues (or sensor itself) . The one mounted on the bell housing... giving wrong or erratic signal. Maybe dig thru wire diagram and trace back to see for sure what the ctis ecu is using to determine speed to verify it is the one on bell housing or not.

Hopefully someone will chime in with better details.

The RPM speed sensor on the belling housing is only for the STE/ICE and if you have a tachometer. It only other ting is it goes thought the frequency divider. This is the STE/ICE connection. Has nothing to do with the CTIS. The speed signal for the CTIS comes from the trans converter.

 

[spankybear]

You need the Y cable to access that ctis control. The Y cable should be part of the msd V3 connection kit.

I have the parts to make the y cable. What do I need to interface with the software?

 

[coachgeo]

The RPM speed sensor on the belling housing is only for the STE/ICE and if you have a tachometer. It only other ting is it goes thought the frequency divider. This is the STE/ICE connection. Has nothing to do with the CTIS. The speed signal for the CTIS comes from the trans converter.

ahhhhhh.... yes that rings a bell. Have you tested that speed sensor in the tranny? think there is only two speed sensors on the whole truck.. bell housing and one in tranny. Didn't someone have pinched harness wires inside the tranny that had similar issue?