D3G XL trans problem

[onemoparnut]

I have a D3G XL and the hydrostatic drive will only move the machine at a very very slow creep unless the throttle is wide open. The throttle or speed selector wont make any difference in speed until you give it full throttle. Once at full throttle the machine works perfectly. My local cat dealer said it could be a bad parking brake switch or the parking brake valve. I changed both and it has made no difference in how the machine operates. It has plenty of power even when it is only creeping I drove it into our loading dock and the tracks just started very slowly digging holes no problem. I also tried to see if there are any codes in the computer but i cannot retrieve any. I connected wire 1 with wire 2 in the black diagnostic connector and nothing happened at all. I was told by a member here that if you connect those 2 wires for a second it should flash the codes through a light in the dash. Anyone have any ideas?

 

[Bob/Ont]

I think your machine is okay. Hystats need full throttle to move, you control speed with drive pump. It should have a throttle cable down to a valve that will slow travel when you throttle down to prevent stalling the engine.
Later Bob

 

[d9gdon]

Bob, these transmissions can be programmed by techs to do different things like making reverse a percentage of forward travel speed (like 150% for example) or limiting the top speeds (one tractor may have a top speed of 6.8 mph while another may have a top speed of only 4 mph depending on owner preference).

He's got something wrong going on with it, cause mine would move at an engine speed barely above idle. Also, there's no mechanical governering of pump as it's all controlled by the machine's computer. If you're in a speed that's too high for the load, the computer automatically destrokes the pump until the load is reduced and then it speeds back up, like a torque converter drive would.

 

[Lee-online]

does it change speed when you increase the speed with your left thumb switch?
does the gage respond?

 

[onemoparnut]

The serial number is cat00d3gljmh02016. The speed does not increase with the left thumb switch unless the throttle is wide open. The gauge does respond at low rpm but the rest of the machine does not.

 

[Lee-online]

Pulling the codes should be the first step. let us know what codes you find.



(2) Harness Code Connector

(3) Service Tool Connector (ET)

(4) Diagnostic Indicator

The service tool connector and the harness code connector are located behind the access cover for the fuse panel. The access cover is above the cab floor on the left side of the machine







To enter service mode, disconnect the machine identification plug from the harness code connector. When the control module is in the service mode the control module's diagnostics are available in order to assist with troubleshooting.

A single diagnostic code is shown. The diagnostic code is on hold. Information is shown on the diagnostic indicator by flashing the indicator ON and OFF. The flashes represent a three digit number. A series of flashes represent the first digit. A one second pause follows the first digit. Another series of flashes represents the second digit. A one second pause follows the second digit. Another series of flashes represents the third digit. Count the number of flashes. The number of flashes determine each digit. A three second pause separates each three digit number. Use table 2 in order to find the correct CID.

When you scroll through the diagnostic codes, the codes for all of the active diagnostic codes are shown one at a time. Ground connector contact 1 in order to scroll through the active diagnostic codes. Remove the ground from connector contact 1 in order to stop scrolling. The diagnostic code that is shown is now on hold. A code of 222 indicates that diagnostic codes are NOT active or logged.

Perform the procedure that corresponds to the diagnostic codes.

Clearing a diagnostic code removes the diagnostic code from the control module's memory. When a problem is corrected, it is necessary to remove the diagnostic code from the memory of the control module. The diagnostic code must be on hold in order to clear an inactive diagnostic code. The control module does not allow active diagnostic codes to be cleared.

Place the diagnostic code on hold.

The diagnostic code is on hold. Ground connector contact 3 in order to remove the logged diagnostic code from the control module's memory. The diagnostic indicator is extinguished after the inactive diagnostic code has been cleared. The diagnostic indicator is extinguished until you scroll through the diagnostic codes. The control module does not allow active diagnostic codes to be cleared.

Repeat the procedure for any remaining diagnostic codes. Return to normal mode when you are finished by replacing the machine identification plug. A diagnostic code of 222 indicates that diagnostic codes are NOT active or logged.

 

[Bob/Ont]

Bob, these transmissions can be programmed by techs to do different things like making reverse a percentage of forward travel speed (like 150% for example) or limiting the top speeds (one tractor may have a top speed of 6.8 mph while another may have a top speed of only 4 mph depending on owner preference).

He's got something wrong going on with it, cause mine would move at an engine speed barely above idle. Also, there's no mechanical governering of pump as it's all controlled by the machine's computer. If you're in a speed that's too high for the load, the computer automatically destrokes the pump until the load is reduced and then it speeds back up, like a torque converter drive would.

Okay Don, that machine is more modern than I have worked on. Last I had much to do with had a throttle link to allow limited pump output for travel without stalling at low throttle. Computer can do more.
Later Bob

 

[onemoparnut]

Ok i was able to get the codes out, I was looking at the wrong light before. The codes are 254, 252, 244, 271, and 141. Thanks for all the help guys.

 

[Nige]

So your codes are ........

254 (CID 1693) - Decelerator Pedal Position Sensor
252 (CID 0468) - Service Brake Pedal Position Sensor
244 (CID 0070) - Parking Brake Rocker Switch
271 (CID 1706) - Proportional Solenoid (Reverse Right Drive Pump)
141 (CID 0190) - Engine Speed Sensor

Have you tried erasing them one at a time just to see if any of them are inactive..? You might be lucky and find you only have 1 or 2 active codes out of the 5 you listed.

 

[Lee-online]

Some are prolly old so clear them all out and see what comes back.

 

[onemoparnut]

I will try erasing them in the morning thanks so much everyone. Should I erase one and run the machine and see if it comes back? Or should I erase them all and run it and see what comes back?

 

[Lee-online]

Just erase them all. If you have an active code it cannot be erased.

 

[Nige]

Try erasing each one in the order you bring it up (so first one first in other words). I'm sure you will find that some of these codes are old ones that once erased will not come back, at least not in the short term. You cannot delete a code that is Active. Erase as many as you can at one hit, you won't need to run the machine.

Erasing whatever you can will leave you with a short list of codes that will not erase. These are the ones you will have to troubleshoot and fix. Once each one is fixed you can then erase it using the same procedure as before. Fixing whatever is causing the codes is most likely to be the answer to your no-drive problem.

 

[onemoparnut]

I was able to erase all the codes the only code I have now is 222. I ran the machine a little and I am still having the same problem. I did notice that if i play with the decelerator pedal the machine will work as it should at times. Can the decelerator pedal sensor cause this problem. I checked the codes again after I ran it and i still have just 222. Should i run it more and see if the codes come back?

 

[Nige]

222 indicates you have no Active Codes, which is good news, so you have no "bad" sensors. You might still have a sensor that's out of adjustment though.

My first thought would be blast the area around the pedal pivots (there are a million bushes in there, or so it seems looking at the Parts Manual) with WD40 or similar, just in case something is hanging up somewhere.

Second thought would be to test the decel pedal sensor & adjust if necessary, the problem is you need Cat ET to do that unless Lee knows a way to do it without. Does the engine speed fall to between 800-900 RPM when you press the declerator pedal..?

Plus I would re-do the adjustment procedure for the brake limit switch if adjusting the decel pedal sensor doesn't fix the problem. I'll e-mail you the procedures.

 

[onemoparnut]

I do not know what the rpm is the machine does not have a tach.

 

[Lee-online]

All the code you had could be the cause. Some times a problems need to be seen by the ECM for a period of time before it logs the code.

Recalibrating is a good idea but you have to use ET. I have fixed these machine with calibrating the joystick. Have no idea why it lost its calibration. A calibration is a good troubleshooting procedure and a machine tune up.

if the speed sensor is reading incorrect, a low RPM then the ECM will destroke the drive pumps because it thinks there is too much load. Remove and clean the speed sensor. Reinstall until it touches the flywheel, then back off 1/2 turn. Its in the flywheel housing on the left side.

 

[Lee-online]

Just found this.

Track-Type Tractor:

D3G (S/N: JMH1-UP)

D4G (S/N: FDC1-UP; HYD1-UP; TLX1-UP)

D5G (S/N: WGB1-UP; RKG1-UP)

Issues with the 189-5746 Speed Sensor Gp. The debris at the tip of the sensor can affect the signal from the sensor. The debris is caused by contact with the starter gear and the flywheel gear. The debris can accumulate at the tip of the sensor.

Remove the 189-5746 Speed Sensor Gp from the engine and clean the tip of the sensor. The sensor should be checked after 1,000 hours of operation. Reinstall the sensor. Check the connection of the connector and the harness for any damage if the problem still exists. If damage is found then replace the speed sensor with a new speed sensor.




(1) 189-5746 Speed Sensor Gp

 

[onemoparnut]

Ok I am going to clean the speed sensor today, I will let you know how it works out. Thanks again for all the help.

 

[Nige]

Remember that as Lee says above, make sure to set the clearance correctly when you re-fit it by turning it until it touches the flywheel, then back out 1/2 a turn and lock the locknut.