2ZK 140H transmission issues

[Wyatt Mattson]

2ZK06764
Just had machine in shop for new radiator, rad hoses, heater hoses and a full transmission service (spotless screens/filter)
Worked a full day after that with no issues

Tried to take it to a job a few days later and no high range (5678F) / (456R)

Have had this happen before with low range so figured it would just be a shift solenoid gone again

ET gave me 4 (logged) codes
None active

644- 3


Transmission Solenoid 4: Voltage Above Normal


644-5


Transmission Solenoid 4: Current Below Normal


644-6


Transmission Solenoid 4: Current Above Normal


168-1


Electrical System Voltage: Low


Changed solenoid #4 out with a full new assembly and still no go

Machine won’t throw any more codes to lead me in one direction or another

I have seen on this forum that transmission ECMs can cause grief as well as shifter assemblies

Hoping someone can lead me in the right direction with no codes as clues

Thanks in advance

 

[Nige]

I have seen on this forum that transmission ECMs can cause grief as well as shifter assemblies

Don't recall seeing that. Highly unlikely, although possible.

Changed solenoid #4 out with a full new assembly and still no go

Hoping someone can lead me in the right direction with no codes as clues

Clutch #4 isn't high range unless you are using a different numbering method to the one to my charts. #8 is high range. It's also engaged in both Neutral and Park which is a good check.

 

[Wyatt Mattson]

Don't recall seeing that. Highly unlikely, although possible.

Clutch #4 isn't high range unless you are using a different numbering method to the one to my charts. #8 is high range. It's also engaged in both Neutral and Park which is a good check.

View attachment 323875View attachment 323876

Nige, this is the photo that i was going off of from my manual solenoid (D) is the one i changed

 

[Nige]

OK, so different illustrations. It's called a "Cat design feature"
Try testing whether solenoid valve "D" is energized with the transmission in both Neutral and Park. If it is then hook a pressure gauge up to the test point and just make sure the clutch is getting pressurized.

 

[Wyatt Mattson]

OK, so different illustrations. It's called a "Cat design feature"
Try testing whether solenoid valve "D" is energized with the transmission in both Neutral and Park. If it is then hook a pressure gauge up to the test point and just make sure the clutch is getting pressurized.

Will update on solenoid voltage tomorrow. so far all I’ve determined is it’s time for new battery’s as every time I go out to test something the battery charger has to be involved to get machine fired up

Also found one wire hanging on by a thread

E946

OR

MG MESH CNTL - Forward Direct

Unsure if that has potential to be the culprit

 

[Nige]

Also found one wire hanging on by a thread

E946

OR

MG MESH CNTL - Forward Direct

Unsure if that has potential to be the culprit

If it is one of the wires feeding the high range clutch then there is a distinct possibility. What does the schematic indicate.? I can’t look at it at the moment.

EDIT: I just took a look at the schematic (I assume you are using SENR9147) and E946 is a wire between the transmission Spd/Dir switch and the powertrain ECM makred "Forward". So IMO it should affect all forward speeds but TBH until you fix the damage you found you won't know one way or the other.

Another thing is that the transmission wiring harness (the short one mounted on the control valve itself) usually cooks on machines with high operating hours and the insulation becomes brittle leading to internal wire failures. If yours is like that I would suggest a replacement. It's shown as #8 on the attachment.

 

[Wyatt Mattson]

Repaired wire break no luck
Testing in park I have good power to solenoid (G)

Meter reading around 1.1V to (D)

Will start testing harnesses back to ecm

 

[Nige]

Testing in park I have good power to solenoid (G)

In park you should also have power on solenoid H (#8) on your diagram. Did you also check that.? I know it’s got nothing to do with high range but you need info regarding whether the correct solenoids are being powered up at the right time.

 

[Wyatt Mattson]

In park you should also have power on solenoid H (#8) on your diagram. Did you also check that.? I know it’s got nothing to do with high range but you need info regarding whether the correct solenoids are being powered up at the right time.

Tested both G and D good power on G but little to none on D

H is functioning correctly

 

[Nige]

If it’s a consistent fault my first thought would be the harness(es) until proved otherwise. If it was the transmission control on the fritz you would think it would set one or more Active Codes

 

[Wyatt Mattson]

Harness continuity tested fine
Traced wires for solenoid D back to the transmission controller and tested voltage there
Only just over 1V coming from controller plug

I agree on the more active codes thought. Really not giving me much to work with

Was at cat dealer today and it’s a good thing I was sitting down when they told me the price of an transmission controller these days

 

[Nige]

Harness continuity tested fine

Try it with a 5A test light rather than a simple resistance test. Sometimes a wire can be hanging on by a thread and show continuity with a multimeter but when you ask it to pass significant current it will fail.

Traced wires for solenoid D back to the transmission controller and tested voltage there
Only just over 1V coming from controller plug

If you did that by back probing try it with the harness disconnected from the controller. There might be something somewhere pulling the voltage down.

 

[Wyatt Mattson]

Update to finish this post out

After a lot of harness testing (thank you Nige for all the help) everything checked out. I ended up tracking down a used transmission controller for testing purposes and now machine is back in action.
Will be sending original TCM out in hopes to have it repaired

 

[Nige]

Considering the cost of a replacement it’s always worth going the extra mile when troubleshooting before declaring an ECM officially dead.