Construction and Road Equipment

Construction and road equipment repair questions? Ask a mechanic ASAP

Connect one-on-one with {0} who will answer your question

This answer was rated:

Having trouble with a TH580B CAT telehandler. It won't

Having trouble with a...

Having trouble with a TH580B CAT telehandler. It won't drive, only does a slight lurch backwards when selecting either forward or reverse. No codes active.

Mechanic's Assistant: What is the complete model and serial number of your machine?

TH580B sn CATTH580TSLH01078

Mechanic's Assistant: Are you fixing this yourself? What have you tried so far?

Yes I am fixing myself. I am a technician but have no access to CAT manuals. I have traced all wires from direction control lever to the transmission controller. I am not getting a signal from the controller to the forward/reverse solenoids. I have powered the solenoids myself and then the machine drives.

Show More
Show Less
Ask Your Own Construction and Road Equipment Question
Answered in 53 minutes by:
10/16/2020
Mechanic: catmastertech, Technician replied 1 year ago
catmastertech
catmastertech, Technician
Category: Construction and Road Equipment
Satisfied Customers: 3,994
Experience: Field service technician for CAT 19 years.
Verified

Hey, sorry to hear you are having these problems. I know that can be frustrating. Hopefully, we can get you back to work quickly. I see no one could help you earlier, and I hope this is not too late to be helpful. Please note that I am not set up for phone calls, you can ignore the site pop-ups. We can post to this chat as much as you like to work through this issue. All experts are not employees, and we work from home in our spare time to answer questions.

Is the small service book icon shown in the hour meter display? It is very strange to not have logged codes in these machines.

Have you ohm tested the data link wires from the direction shifter to the ECM?

Often, I find the F-N-R shift handle is the fault if the wiring is not damaged under the machine.

Ask Your Own Construction and Road Equipment Question
Customer reply replied 1 year ago
I ohm tested the data link wires yesterday. I don't believe the icon is on. I checked through the codes earlier today and while many were stored (probably from all the testing I've done) there were no active ones. I did find the brake pedal had no free play and therefore the brake pressure switch was keeping it from driving. After making the adjustment it drove perfect for about 3 minutes then went back to not driving.
Mechanic: catmastertech, Technician replied 1 year ago

You should have a neutralizer de-activate switch on the dash to turn that control off.

I think it is on the left side of the wheel.

Ask Your Own Construction and Road Equipment Question
Customer reply replied 1 year ago
Yup I realized that when I was dealing with the pressure switch. In no position does it make a difference.I find it so odd that 3 times this week I've been able to get it to drive for a few mins then it quits again without any fault light coming on in the dash.
Mechanic: catmastertech, Technician replied 1 year ago

It should allow you to choose when you want to the brake pedal to disconnect the transmission or not to disengage it.

Is if possible the switch is bad?

If the ECM see the brake pressure switch it will want to disconnect the drive. This is an operation control so, it will not show as a fault.

Ask Your Own Construction and Road Equipment Question
Customer reply replied 1 year ago
It's a possibly. The light on the switch comes on when activated.
Mechanic: catmastertech, Technician replied 1 year ago

That would mean the switch is wired but, the wiring between the switch and the ECM may have a short.

Ask Your Own Construction and Road Equipment Question
Customer reply replied 1 year ago
Do you know what the ohm reading should be for the brake pressure switch? Could possibly be physically stuck since the brake pedal was partially pressed in for a long time?
Mechanic: catmastertech, Technician replied 1 year ago

It is a normally open switch and closes when it has pressure. CAT does not show the pressure setting or any ohm reading. Normally, it should be less the 5 ohms when closed to have a complete circuit.

It looks like this is using a floating ground at the pressure switch and dash switch. I would double check cab, frame, engine and battery grounds.

Ask Your Own Construction and Road Equipment Question
Customer reply replied 1 year ago
Ok I will do that tomorrow. Thank you.
Mechanic: catmastertech, Technician replied 1 year ago

Glad I could help!

Thank you for using JustAnswer, if you do need further help please let me know.

If you are satisfied with my service, please take a moment to provide a rating.

Thanks again, Don

CATMASTERTECH

Ask Your Own Construction and Road Equipment Question
Customer reply replied 1 year ago
Even if that pressure switch had failed when I turn the neutralizer deactivate switch on it should continue to drive correct? It would be unusual for both to have failed.
Mechanic: catmastertech, Technician replied 1 year ago

Yes but, I am suggesting it may be a short to ground on the wire from the neutralizer switch that is instructing the ECM to see the brake pressure switch which you said earlier was sticking.

Ask Your Own Construction and Road Equipment Question
Customer reply replied 1 year ago
Ahh I see. Will do more checking tomorrow. Thanks!
Mechanic: catmastertech, Technician replied 1 year ago

You're welcome!

Ask Your Own Construction and Road Equipment Question
Customer reply replied 1 year ago
Good morning. If I give the rating now does it mean that the end of the conversation or can I still reply to you once I've done the tests we talked about yesterday?
Mechanic: catmastertech, Technician replied 1 year ago

Questions will go dead in a few days. Ratings can change the status and may slow responses but, I will be notified either way.

catmastertech
catmastertech, Technician
Category: Construction and Road Equipment
Satisfied Customers: 3,994
Experience: Field service technician for CAT 19 years.
Verified
catmastertech and 87 other Construction and Road Equipment Specialists are ready to help you
Ask your own question now
Customer reply replied 1 year ago
Can you please send me an electrical schematic of the drive system? I want to confirm wiring from FNR control to ECU and from ECU to solenoids prior to ordering a new controller or FNR switch. Thank you.
Customer reply replied 1 year ago
Is there a way to test the fnr switch? Brake switch wires are good.
Mechanic: catmastertech, Technician replied 1 year ago

CAT does not have a schematic of the power train system that is readable. It will not show clear in any way I could print.

See your dealer and ask for the Schematic part number RENR9863, maybe they will order it for you without requiring you to purchase the whole book.

CAT does not have any troubleshooting or testing for the FNR control, it only says to try a new one when you suspect it has failed. However, most dealers will not allow returns for electrical parts.

I can pull out a few images from a schematic that can show some of the circuit. CAT has a different drawing style that does not show the complete path or use any type of ladder diagram.

We are not allowed to share copyrighted material per site policy.

Ask Your Own Construction and Road Equipment Question
Customer reply replied 1 year ago
Ok thanks. Can you tell me if the speed sensor(###) ###-####has failed would it not drive? We found that as soon as we remove the driveshafts from the trans everything works because it sees speed from the output sensor as it slowly rotates in neutralOnce we reinstall the driveshafts it once again will not work.
Mechanic: catmastertech, Technician replied 1 year ago

I would think it should engage and drive in one speed only, any shifting would cause a fault without working speed sensors. This is normally what you find with other transmissions. You must also, consider the engine speed sensor, and the torque converter speed sensor for shifting parameters.

The calibration of the shift rail sensors has always been an issue and could be a fault here. They should create codes whenever they have an issue.

Without CAT ET to troubleshoot the controls, inputs, and outputs, it is hard to say where the root cause is located.

Below is a list of items to check when troubleshooting this transmission. I also included some test from a service guide for this transmission.

---

Transmission Interlocks

Before Troubleshooting a transmission fault ensure that there are no Active faults or Interlocks which will neutralise the transmission. The Interlock are generated under the following conditions:

Open or Short circuit to directional or modulation solenoids

Active fault on the transmission shift lever

System over voltage recorded (over 16 volts)

System under voltage recorded (below 9 volts)

Parking Brake engaged or an active fault on the brake

Rear Axle lock system engaged

Neutraliser switch energised

Machine has been switched to operate in Access Platform mode

An invalid key has been used with Machine Security System installed.

Lateral Stability Inhibit system activated.

Anti-roll back.

Loss of Gears and Drive with Shift Rail in Gear

Troubleshooting

Turn the machine off and leave powered down for a minimum of 30 seconds, re-start the machine and check for the sensors moving, this is seen by using Electronic Technician on status screen group 8 � Transmission shifting. When the machine is started the shift rails should neutralise. This can be seen as the shift rail position sensors should be at 0mm(+/-1.0mm).

If the shift rails do not neutralise it would suggest either a modulation valve or shift rail control valve issue. If a shift rail control valve is stuck the position sensors can give an indication of which valve should be replaced.

Shift rail #1 - In gear position

1st Gear +10mm (+2.0/-0.5mm)

2nd Gear -10mm (+2.0/-0.5mm)

Shift rail #2 - In gear position

3rd Gear +10mm (+2.0/-0.5mm)

4th Gear -10mm (+2.0/-0.5mm)

Shift rail #3 - In gear position

5th Gear 10mm (+2.0/-0.5mm)

NOTE : These measurements are approximate and may vary by machine.

The diff lock control valve can be swapped out to test which shift rail valve is faulty if no spare valve is available.

Loss of Gears / Drive � Position Sensor

Intermittent loss of gears on one of the shift rails can be related to the position sensor.

Symptoms

Gears engage correctly when the machine is cold. As the machine reaches normal working temperature (approx 60 deg C) one or two of the gears cannot be engaged, however the other gears continue to work.

Checks

Are the gears being lost on the same shift rail ? Through ET check status screen group 8, and monitor the amount of movement on the Position sensor when cold & at working temperature.

Loss of Gears / Drive � Parking Brake

Symptoms

The transmission drive intermittently drops out and is re-established after cycling the transmission lever through neutral.

Checks

Check Parking brake is not actuated, check parking brake switch located under lever is correctly set and functional.

Loss of Gears / Drive � Internal Fault

Symptoms

Transmission drops out and cannot be re-established by cycling the transmission lever through Neutral.

All Gears and directions can be selected and appear on the dash.

Pressures are OK on both the clutches and Shift rails.

Slight Bearing noise can be heard from the bell housing when engine shut-off

No fault codes shown on ET.

Checks

Check all transmission pressures are within the transmission requirements and no external sensors or valves appear damaged.

Possible root cause

Internal damage to transmission gear drive, or bearing failure.

Loss of Gears During Driving � Gear Train Drag

Symptoms

Transmission drops out and cannot be re-established by cycling the transmission lever through Neutral.

All Gears and directions can be selected and show on the dash.

Pressures are OK on both the clutches and Shift rails.

No fault codes shown on ET

Torque converter speed drops and engine lugs

In neutral the machine tries to move in one direction and/or the engine lugs.

Checks

Check clutch solenoid pressure whilst in Neutral � Pressure should be 0 kPa

Open ET status screen group 6 and check intermediate shaft speed at working temperature at both high and low engine speed. The speed should be 0 rpm at both high and low idle.

Possible root causes

Internal transmission bearing failure causing drive across idler gears

Clutch solenoids pilot being blocked causing the valve to stick

Leakage across clutch shaft rotating seals or clutch valve block seals

Clutch pistons leaking

Torque Converter Stall Speed Low

Symptoms

While performance testing the torque converter, engine stall speed is not met

Checks

Type of fuel being used, Low cetane rating can cause reduced engine performance

Measure torque converter Pressure and flow

Torque converter internal spragg clutch failed

Main implement pump pressurised.

Problem List
The machine will not move when FORWARD or REVERSE speeds are selected.
One or more speeds cannot be selected.
The transmission will not stay in the selected gear.
It is difficult to select the transmission speed.
The transmission is noisy in FORWARD gears.
The transmission is noisy in REVERSE gears.
The transmission system overheats.

Probable Causes

The Machine Will Not Move When FORWARD Or REVERSE Speeds Are Selected
The problem can be caused because of an active interlock. Check for active interlocks. See Systems Operation, "ELECTRICAL FUNCTION REQUIREMENTS" for information concerning machine interlocks for your machine.
There is a failure in the wiring harness.
The boom has exceeded the critical angle and the machine is in the rear axle locked mode. (Earlier Machines)
There is an active diagnostic code for the transmission.
The critical angle sensor has failed.
The parking brake is either ON or the parking brake is ON due to a failure.
The lever for the FORWARD or REVERSE has failed.
Power train oil level is not within the specification.
A transmission solenoid has failed.
There are damaged torque converter components.
The differential drive is damaged.
The neutralizer switch has failed.
The transmission is not calibrated.
System voltage is above 16 DCV.
System voltage is below 10 DCV.
A transmission solenoid has failed.
An air leak on the inlet side of the transmission pump.
The transmission pressure relief control valve is not set correctly.
FORWARD and REVERSE clutch packs are worn or damaged.
FORWARD and REVERSE clutch piston seals are leaking.
The transmission pump is worn or damaged.

One Or More Speeds Cannot Be Selected
The machine ECM may not be configured properly. See Testing and Adjusting, "ELECTRONIC CONTROL MODULE (ECM) - CONFIGURE" for information concerning the machine configuration.
The speed selection shifter fork is damaged.
Assemblies for the shift rod are damaged.
A synchronizer is damaged.
There are damaged gears in the transmission.
A transmission solenoid has failed.
The engine speed sensor has failed.
The intermediate speed sensor has failed.
The output speed sensor for the torque converter has failed.

The Transmission Will Not Stay In The Selected Gear.
A transmission solenoid has failed.
The engine speed sensor has failed.
The intermediate speed sensor has failed.
The output speed sensor for the torque converter has failed.
The detent spring for the transmission selector lever is damaged.
The shift fork is damaged.
The spring loaded split pin for the synchronizer is damaged.
The parking brake has an intermediate failure.

It Is Difficult To Select The Transmission Speed
The speed selection shifter fork is damaged.
Assemblies for the shift rod are damaged.
A synchronizer is damaged.
The FORWARD or REVERSE clutch is staying engaged.

The Transmission Is Noisy In FORWARD Gears
Transmission oil level is too low.
The relief pressure for the transmission pump is too low.
The transmission gears are worn or damaged.
The transmission shaft bearings are worn or damaged.
The transmission needs to be calibrated.

The Transmission Is Noisy In REVERSE Gears
Transmission oil level is too low.
The lube pressure for the transmission is too low.
The transmission gears for the REVERSE shaft are worn or damaged.
The bearings for the REVERSE shaft are worn or damaged.
The transmission needs to be calibrated.

The Transmission System Overheats
The application for the machine is not correct.
The machine is not being operated correctly.
The scavenge pump for the transmission is not operating correctly.
There are leaks in the suction side of the transmission oil pump.
The transmission oil pressure is too low.
A direction clutch is slipping.
There may be an obstruction in the oil cooler.
The transmission oil cooler lines may be plugged or damaged.
The transmission oil pump is worn or damaged.
The torque converter inlet relief valve is stuck open.
The oil viscosity is not the correct viscosity.
The transmission oil temperature gauge has failed. The problem could be between the sensor, the ECM, and the display.
The ECM will display an error.

Ask Your Own Construction and Road Equipment Question
Was this answer helpful?

How JustAnswer works

step-image
Describe your issueThe assistant will guide you
step-image
Chat 1:1 with a mechanicLicensed Experts are available 24/7
step-image
100% satisfaction guaranteeGet all the answers you need
Ask catmastertech Your Own Question
catmastertech
catmastertech
catmastertech, Technician
Category: Construction and Road Equipment
Satisfied Customers: 3,994
3,994 Satisfied Customers
Experience: Field service technician for CAT 19 years.

catmastertech is online now

Related Construction and Road Equipment Questions
Connor is my name, I have a Cat TH460B serial number
Hello, Connor is my name, I have a Cat TH460B serial number SLF00643 , occasionally it will drive forward only but mostly it will roll forward a bit twice and then module puts it in neutral again. I w… read more
Daniel Wilson
Daniel Wilson
Auto Mechanics 1&2/diesel mech
1,215 satisfied customers
I have a Cat D5K that when I put it reverse it starts to
Hi I have a Cat D5K that when I put it reverse it starts to backup but after about a foot it suddenly stops. The red exclamation mark starts to flash and park brake light it will not move any directio… read more
catmastertech
catmastertech
Technician
Vocational, Technical or Trade Scho
3,994 satisfied customers
I have a LW130 that will goin reverse but not forward,
I have a LW130 that will goin reverse but not forward … read more
Daniel Wilson
Daniel Wilson
Auto Mechanics 1&2/diesel mech
1,215 satisfied customers
I have a JCB 508C Telehandler. It moves forward or backward
I have a JCB 508C Telehandler. It moves forward or backward 10 feet then stops moving. When you switch off and switch back on after a couples minutes, it moves again about 10 feet. … read more
Bobcat Master
Bobcat Master
self-employed
Diesel technology
39 satisfied customers
I have a th63 telehandler that only goes in reverse or
I have a th63 telehandler that only goes in reverse or forward in 3rd or 4th gear. No first or second gear. You can feel the machine engage from neutral to first or second but no movement. Parking bra… read more
catmastertech
catmastertech
Technician
Vocational, Technical or Trade Scho
3,994 satisfied customers
My 2009 JLG 10054 wont go into gear in either forward or
My 2009 JLG 10054 wont go into gear in either forward or reverse. … read more
Curtis B.
Curtis B.
Technician
Associate Degree
2,324 satisfied customers
I have a 2001 New Holland LB90 Backhoe. I have two solenoids
Hi there I have a 2001 New Holland LB90 Backhoe. I have two solenoids one for reverse one for forwards located ontop of the transmission. My machine doesn't drive forwards or backwards and I checked t… read more
Curtis B.
Curtis B.
Technician
Associate Degree
2,324 satisfied customers
I have a JCB 530 which is not moving forward nor backward.
Hello! I have a JCB 530 which is not moving forward nor backward. The problem started with few second delay in mowing than is not moving at all. I saw that on the transmission there is an oil sensor w… read more
RyanY78
RyanY78
208 satisfied customers
Cat 420d ok getting it narrowed down would like for you to
cat 420d ok getting it narrowed down would like for you to identifie which sol are sol 3 , sol 4 ,and sol 6… read more
Daniel Wilson
Daniel Wilson
Auto Mechanics 1&2/diesel mech
1,215 satisfied customers
Happy new year. Back again, I had some emails last winter
hello Happy new year . Back again, I had some emails last winter about mu cat th 360b that has a shifting problem. Is has been working ok for some months now. Now and runnning and stopping. But now, r… read more
catmastertech
catmastertech
Technician
Vocational, Technical or Trade Scho
3,994 satisfied customers
I have a CH55 Cat Challenger that won't hardly move in
Hello- I have a CH55 Cat Challenger that won't hardly move in forward or reverse. It is flashing an F329 fault code. Any suggestions on how to fix on my own? … read more
catmastertech
catmastertech
Technician
Vocational, Technical or Trade Scho
3,994 satisfied customers
My customer has a CAT 259 skid steer. They were compressing
My customer has a CAT 259 B skid steer. They were compressing garbage with the bucket now the left track is locked and a check light is blinking. Is there a way to access the code without a scan tool?… read more
Daniel Wilson
Daniel Wilson
Auto Mechanics 1&2/diesel mech
1,215 satisfied customers
I have a Cat TL943 Telehandler. When you put the machine in
I have a Cat TL943 Telehandler. When you put the machine in drive, it gives you a little hesitation to move both forward and back but won't drive in any direction. … read more
Curtis B.
Curtis B.
Technician
Associate Degree
2,324 satisfied customers
I have a 2004 caterpillar 287b track machine. Joystick
I have a 2004 caterpillar 287b track machine. Joystick control. When going forward, I let go of joystick to center position to stop and the machine comes to a stop but also turns to the right. Then it… read more
Daniel Wilson
Daniel Wilson
Auto Mechanics 1&2/diesel mech
1,215 satisfied customers
420e cat backhoe. Loud screeching from rear of engine when
420e cat backhoe. Loud screeching from rear of engine when shift into forward. Engine belts are all tight. Will not shift into 4th forward. 1-3 forward and 1-3 reverse work normal although engine spee… read more
catmastertech
catmastertech
Technician
Vocational, Technical or Trade Scho
3,994 satisfied customers
I have an Akerman H12blc excavator, made around 1987. When
I have an Akerman H12blc excavator, made around 1987. When I tensionsed a track to its 19.5 cm spec, it compressed the idler spring, and when I tried to run the excavator it would only go straight ahe… read more
catmastertech
catmastertech
Technician
Vocational, Technical or Trade Scho
3,994 satisfied customers
Cat 420E: I have a cat 420 E backhoe I am having a problem
I have a cat 420 E backhoe I am having a problem with the extendable stick checked the switch power to it but no power at solenoid there is also a problem with trans it pops out of 3&4 it s a4 speed a… read more
catmastertech
catmastertech
Technician
Vocational, Technical or Trade Scho
3,994 satisfied customers
Hey I got that roller all done it was the pump drum
Hey I got that roller all done it was the pump for the drum moter and i fixed the brake leak too . anyway i am working on a 938H SN PREFIX MJC01029 Unit is getting stuck in 2ed gear in foward and reve… read more
catmastertech
catmastertech
Technician
Vocational, Technical or Trade Scho
3,994 satisfied customers
Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

JustAnswer in the News:

Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.

What Customers are Saying:

Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help.

Mary C.Freshfield, Liverpool, UK

This expert is wonderful. They truly know what they are talking about, and they actually care about you. They really helped put my nerves at ease. Thank you so much!!!!

AlexLos Angeles, CA

Thank you for all your help. It is nice to know that this service is here for people like myself, who need answers fast and are not sure who to consult.

GPHesperia, CA

I couldn't be more satisfied! This is the site I will always come to when I need a second opinion.

JustinKernersville, NC

Just let me say that this encounter has been entirely professional and most helpful. I liked that I could ask additional questions and get answered in a very short turn around.

EstherWoodstock, NY

Thank you so much for taking your time and knowledge to support my concerns. Not only did you answer my questions, you even took it a step further with replying with more pertinent information I needed to know.

RobinElkton, Maryland

He answered my question promptly and gave me accurate, detailed information. If all of your experts are half as good, you have a great thing going here.

DianeDallas, TX

< Previous | Next >

Meet the Experts:

Curtis B.

Curtis B.

Technician

2,324 satisfied customers

Technican turned service manager with multiple lines of equipment and rental units.

Wayne

Wayne

Journeyman

1,298 satisfied customers

worked on many road graders, Bull dozers , skid steers, Rollers

Cat Man

Cat Man

Cat Engine Expert

578 satisfied customers

I am ASE Master Certified.

dieseldan55

dieseldan55

Mechanic

299 satisfied customers

Road Mechanic for Volvo Construction Equipment.

Chris (aka- Moose)

Chris (aka- Moose)

Technician

85 satisfied customers

24 years of experience diagnosing & repairing

Steve

Steve

Mechanic

42 satisfied customers

Heavy Equipment Mechanic for 25 years

JBFixxer

JBFixxer

Mechanic

22 satisfied customers

16+ years experience, hydraulics,hydrostatics, engines, fuel injection systems. And everything in between.

< Previous | Next >

Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Show MoreShow Less

Ask Your Question

x