Transmission trouble

[Overboard]

I have an m1045A2 (planetgov) and ever since I got it the trans light stays on. The light comes on as soon as I turn power on crank it up, until I turn the truck off. I used the diagnostic approach, jumped A and E, this is where it gets really frustrating it just flashes 12 over and over, no code. I drove it and it shifts fine now granted its not street legal so I stay in the development but it went into 3rd gear fine. Fluid level is perfect and clean. I've tried going through the TMs, but besides the trans light being on I have nothing else to go on,, and maybe I'm looking in the wrong spot, ive searched the internet and I cant seem to find an answer so maybe you all can help me out.

 

[DREDnot]

A basic shifting diagnosis will be hard to pull off if you cant get up to 45MPH at least to catch OD and converter lock up bumps.

Does the trans shift into all four gears while in OD position?
When manually shifted from 1 to 2, 2 to D, and D to OD, does it shift as commanded?
Can you feel the torque converter lock up at steady cruise?

Have you tried resetting the red trans reset button that is behind the passenger seat?

While you are in that rats nest behind the rear battery compartment wall, look around and see if the wiring there looks in original condition, Or has it been obviously tampered with?

Also , cast your eye on all the sensor wiring you can see from underneath looking up around the trans pan area. Looking for any obvious contrafibularities

 

[badgerd]

I remember a thread about the same thing and it was a failing/failed TCU. Replaced and the “constant trans light” went away.

If it’s shifting like normal and no codes, that’s a pretty likely candidate…


Sent from my iPad using Tapatalk

 

[Overboard]

A basic shifting diagnosis will be hard to pull off if you cant get up to 45MPH at least to catch OD and converter lock up bumps.

Does the trans shift into all four gears while in OD position?
When manually shifted from 1 to 2, 2 to D, and D to OD, does it shift as commanded?
Can you feel the torque converter lock up at steady cruise?

Have you tried resetting the red trans reset button that is behind the passenger seat?

While you are in that rats nest behind the rear battery compartment wall, look around and see if the wiring there looks in original condition, Or has it been obviously tampered with?

Also , cast your eye on all the sensor wiring you can see from underneath looking up around the trans pan area. Looking for any obvious contrafibularities

I was able to get it out and took the risk I got it up to 50 now I fist went through 1 to 2 to d to OD all went great no problems at all reached all four gears in OD and felt torque conveyer lock up
I checked the red button it's not popped meaning pressing it did nothing, no movement, as for wiring it looks good besides shooting each wire I would say it's fine

However I will say this the trans light lights up when I go to run nice and bright but when I start the truck it dims to barely noticeable but clearly lit. Then as soon as I shut I off goes out don't know if that's something, just another observation.

 

[DREDnot]

My understanding is The red button is more like a reboot button than a circuit breaker.

The dim light may be a clue. I would check/clean the connectors to the light that are located under the floor in front of the shifter bag.
Another possibility Ive read about is stray voltage from a failing relay causing a false trans light.

At least the trans is functional and its seemingly a false light

 

[Action]

The red button is attached to a resetable circuit breaker.

 

[Overboard]

My understanding is The red button is more like a reboot button than a circuit breaker.

The dim light may be a clue. I would check/clean the connectors to the light that are located under the floor in front of the shifter bag.
Another possibility Ive read about is stray voltage from a failing relay causing a false trans light.

At least the trans is functional and its seemingly a false light

Tomorrow I will be installing the reverse switch so I'll be in the neighbor hood and I'll look at all the wiring for the light hopefully it's that, possible a bad ground.

 

[Retiredwarhorses]

Open the TCM box up and see if it’s full of water
This is a common issue

 

[Overboard]

Open the TCM box up and see if it’s full of water
This is a common issue

Bone dry

 

[Retiredwarhorses]

Bone dry

worth a try…have you unplugged the cannon plug and inspected pins on plugs for any corrosio?
sometimes just reseating the plug can clear up a connection issues.
In the shop environment, I can just throw another TCM at it, unfortunately that’s not an option for the normal owner.

 

[Overboard]

worth a try…have you unplugged the cannon plug and inspected pins on plugs for any corrosio?
sometimes just reseating the plug can clear up a connection issues.
In the shop environment, I can just throw another TCM at it, unfortunately that’s not an option for the normal owner.

Yes I unplugged it inspected the pins everything looks great, i don't know if another TCM would be the solution, only bc the one that is in it looks brand new. i just got done with the reverse switch. I went over all the wiring took the light out tested for bad grounds and everything looks really good. I looked at the wiring around the transmission and it all looks good. Now this truck has only 82 miles on it. That and the fact that everything and i mean everything is labeled inside with label maker labels, I'm guessing this was a training vehicle and either kept inside or in a warehouse bc there really isnt any corrosion. I think honestly the reason its so dirty is bc it was DRMO'd and left outside. All that said i have no idea what to look for let alone besides a dim trans light nothing seems to be wrong.

 

[DREDnot]

Looking at the schematic from the TM 9-2320-387-24-2 for the M1114 sheet 2...

The light should get 12v power from the transmission relay directly to wire 657B.
Wire 657A then goes directly to the TCM housing cannon plug terminal U then thru to the TCM module pin B9 (check trans lamp).
Im assuming that the TCM controls ground for the lamp to illuminate. So somewhere in those few wires, or internally in the components themselves there is some stray ground or voltage causing the lamp to light. May be as simple as a blown diode in the lamp itself. Could be a drop of moisture between two pins of the patch cable between the cannon plug and the TCM itself. For that I'd disconnect and detail inspect and blow dry with compressed air. It could be a bad TCM.

Im thinking check for continuity to ground at the body side of the 657A connector when OFF, when ON, and with the engine running.
The answer should be NO, YES, NO....I think...
If NO, YES, YES, then the TCM is geeking.
Then I would check for voltage OUT of the lamp at lamp side of 657A connector....also when OFF, ON, and engine running. Not sure the correct readings but post what you get. All the while looking for any pinched or over tensioned wire anywhere.

Just spitballing from a distance here.

 

[Overboard]

Looking at the schematic from the TM 9-2320-387-24-2 for the M1114 sheet 2...

The light should get 12v power from the transmission relay directly to wire 657B.
Wire 657A then goes directly to the TCM housing cannon plug terminal U then thru to the TCM module pin B9 (check trans lamp).
Im assuming that the TCM controls ground for the lamp to illuminate. So somewhere in those few wires, or internally in the components themselves there is some stray ground or voltage causing the lamp to light. May be as simple as a blown diode in the lamp itself. Could be a drop of moisture between two pins of the patch cable between the cannon plug and the TCM itself. For that I'd disconnect and detail inspect and blow dry with compressed air. It could be a bad TCM.

Im thinking check for continuity to ground at the body side of the 657A connector when OFF, when ON, and with the engine running.
The answer should be NO, YES, NO....I think...
If NO, YES, YES, then the TCM is geeking.
Then I would check for voltage OUT of the lamp at lamp side of 657A connector....also when OFF, ON, and engine running. Not sure the correct readings but post what you get. All the while looking for any pinched or over tensioned wire anywhere.

Just spitballing from a distance here.

Thank you gonna try that today will post results

 

[Overboard]

Looking at the schematic from the TM 9-2320-387-24-2 for the M1114 sheet 2...

The light should get 12v power from the transmission relay directly to wire 657B.
Wire 657A then goes directly to the TCM housing cannon plug terminal U then thru to the TCM module pin B9 (check trans lamp).
Im assuming that the TCM controls ground for the lamp to illuminate. So somewhere in those few wires, or internally in the components themselves there is some stray ground or voltage causing the lamp to light. May be as simple as a blown diode in the lamp itself. Could be a drop of moisture between two pins of the patch cable between the cannon plug and the TCM itself. For that I'd disconnect and detail inspect and blow dry with compressed air. It could be a bad TCM.

Im thinking check for continuity to ground at the body side of the 657A connector when OFF, when ON, and with the engine running.
The answer should be NO, YES, NO....I think...
If NO, YES, YES, then the TCM is geeking.
Then I would check for voltage OUT of the lamp at lamp side of 657A connector....also when OFF, ON, and engine running. Not sure the correct readings but post what you get. All the while looking for any pinched or over tensioned wire anywhere.

Just spitballing from a distance here.

Ok so as far as continuity it's no, yes, no
And voltage on 657a is 0 off .018 at run and 10.17 engine running

No crimped wires or anything and plug to tcm looks good


I also tested voltage off of 657b and I got 0 then 12 on run and running I'm getting 11 volts

 

[DREDnot]

Hmmm....check the voltage of each battery individually, then check for the voltage of the pair, then check voltage at the batteries while running(generator output). Lastly, check voltage at the 12v stud on the front of the generator.

This is probably the stuff to check first in any electrical diagnosis...just to make sure the system is fully capable of supplying the electrons in the first place.

Check for any voltage from the 657A body side(off,on,running). There shouldnt be any. (trying to eliminate TCM as the cause)

Swap the trans light wires to the T/C light and see if it still stays lit while running? (trying to eliminate a bad lamp LED)

Just a few sunday thoughts from the hot garage

 

[Overboard]

Hmmm....check the voltage of each battery individually, then check for the voltage of the pair, then check voltage at the batteries while running(generator output). Lastly, check voltage at the 12v stud on the front of the generator.

This is probably the stuff to check first in any electrical diagnosis...just to make sure the system is fully capable of supplying the electrons in the first place.

Check for any voltage from the 657A body side(off,on,running). There shouldnt be any. (trying to eliminate TCM as the cause)

Swap the trans light wires to the T/C light and see if it still stays lit while running? (trying to eliminate a bad lamp LED)

Just a few sunday thoughts from the hot garage

I have .048 volts coming off the 657a body side while running, I'm assuming this is the TCM then?

 

[DREDnot]

Voltages at the batteries and generator within spec?

Same light results when the wires are switched to the T/C lamp?

If so, it sounds like there may be stray voltage backfeeding through that wire.

Anybody else got any ideas on this one?

 

[Overboard]

Voltages at the batteries and generator within spec?

Same light results when the wires are switched to the T/C lamp?

If so, it sounds like there may be stray voltage backfeeding through that wire.

Anybody else got any ideas on this one?

I got two brand new batteries I know they are good and I swapped out the light,

Could I swap a TCM from a 1097a2 to this truck to rule it out both have non-turbo 6.5 4speed transmission?

 

[Action]

I got two brand new batteries I know they are good and I swapped out the light,

Could I swap a TCM from a 1097a2 to this truck to rule it out both have non-turbo 6.5 4speed transmission?

So what happened with the other light plugged in? The same thing?
Yes, you can swap the entire tcm box. Shift points changed thru the years.

 

[Overboard]

So what happened with the other light plugged in? The same thing?
Yes, you can swap the entire tcm box. Shift points changed thru the years.

Ok the 1097a2 is a 95 and the 1045a2 is a 05 so if i swap out the entire box and still get light we can rule out TCM and the light did same dim i also checked the light itself fed it steady 12 right off battery and checked for continuity in case the light itself was messed up.