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catmastertech
catmastertech, Technician
Category: Heavy Equipment
Satisfied Customers: 1882
Experience:  19 years Cat, 3 years Case
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wont work..forward gears but works in reverse

Customer Question

980F Transmission neutralizer won't work in forward gears but works in reverse. Any ideas?
Submitted: 2 years ago.
Category: Heavy Equipment
Expert:  catmastertech replied 2 years ago.

I would like to help on this, could you send me your serial number?

It will take some time for me to research this, you have already done what I would check. I have had a bad switch with a broken internal spring disconnect in turns and work fine when straight. Even a wire break contact in turns but, not reverse to forward.

 

Customer: replied 2 years ago.
Thanks Donnie. SN is 08JN00527. I also just checked the selenoids (switched the forward and reverse wires) and the selenoids are fine. It seems to be something to do with the power lead to forward neutralizer ... the forward wire doesn't cut the power out like it should ...
Expert:  catmastertech replied 2 years ago.

OK, I am glad I looked at the system. This is different than what I was thinking.

This tractor still uses brake pressure but, it works with the electronic shift transmission. The system operates the neutralizer as follows.

During normal operation, neutralizer switch closes the neutralizer input of the shift handle (9 contact connector - contact 1) to battery voltage. Depressing the left brake pedal increases the brake oil pressure and opens the neutralizer input line. With this line open, the shift handle cannot close either direction solenoid input of the control (connector contacts 18 and 19) to battery voltage. Without battery voltage at one of these inputs the control neutralizes the transmission. With the transmission neutralized, the direction solenoids are not activated.

 

So, I believe you have a wire loosing contact when if forward and can maintain its connection in reverse.

Power comes from the fuse (126 pink wire) for the transmission shifter fuse and passes through the pressure switch to the (720 purple wire) transmission shifter control. The override switch will send power to this same wire when the switch is on (indicator light will be on also).

 

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Let me know if you need more information on this. I hope this covers it, I have had loose connectors on the shifter do this. Try turning on the override switch to see if it works the same. If it does, the problem may be in the cab wiring.

Customer: replied 2 years ago.

Thanks Donnie. First of all, this 980F has an air over hydraulic system. It's an older F. The newer F's and the G's are only hydraulic systems.

 

Secondly, I already checked the wiring as you indicated in your answer and that's not the problem.

 

Another indication of the problem is when the loader is started in the neutral, it will not go into forward or reverse. I just learned to "trick" it by starting it and quickly putting it in gear before it completely powers up and I run it like that. If it's put in neutral, it won't go into gear again (forward or reverse).

 

The override switch works in reverse but makes no difference in forward.

 

It's stumped the best of the Finning techs ... we've already had them out ... twice ...

Expert:  catmastertech replied 2 years ago.

I thought it should be air over hydraulic but, the manual said oil.

Could you explain the problem with override switch to me a little more? Does it prevent the transmission disconnecting in reverse but, still allow it to disconnect in forward when it is on?

To me, that would indicate the power is lost to the shifter even if the override switch is on.

Have you replaced the shifter control (handle)?

Have you checked the power to the shifter on the 720 purple wire to see if it drops out?

Customer: replied 2 years ago.

When the override switch is on, the tranny disconnects in reverse like it should, but it does not disconnect when in forward.

 

Yes, we did try a new shifter control (handle) and it made no difference.

 

Yes, we checked the 720 purple wire and it cuts out when the switch is on and in reverse but does not when the switch is on and in forward. There is continuous power when in forward, whether the switch is on or off.

Expert:  catmastertech replied 2 years ago.

Yea, this is a weird one.

What happens when you leave the override switch disconnected?

What happens when the pressure switch is unplugged?

What happens when you leave both the switch and pressure switch unplugged?

Customer: replied 2 years ago.

My apologies but I re-checked the 720 purple wire today and power in the wire DOES cut out when the switch is on and in forward, just as it cuts out when in reverse, but it doesn't kick the tranny out when in forward.

 

I just installed a new neutralizer switch and nothing changed. Never left the switch disconnected because it wouldn't affect this forward/reverse issue.

 

When I unplugged the pressure switch it was like having the switch off ... the tranny never kicks out when the brake is applied in forward or reverse.

 

Not sure what you mean by "unplugging" the "override" switch. I call it a neutralizer switch and there are 5 wires connected to it that have to be unscrewed. There is no "plug".

Expert:  catmastertech replied 2 years ago.

Thanks for the reply. I am confusing myself enough by thinking of later versions of this setup for medium loaders. Sorry if I am making it more confusing for you too. Some models, the neutralizer works when the light is on and some when the light is off. I am thinking 938G the light is off but, 950G the light is on when the pedal will disconnect the transmission.

 

So, if I was reading your reply correctly, the light is on when the neutralizer is on and the pedal disconnects the transmission.

 

What I wanted to know is what happens when the 720 purple wire is disconnected from the neutralizer switch and the pressure switch is connected?

 

Then I wanted to see what happens when the pressure switch is disconnected and the neutralizer switch is connected and with the switch flipped to the off position (sending power to the shifter without the pressure switch in the circuit).

 

Then (for shits and giggles) lets see what happens when both the neutralizer switch and the pressure switch is disconnected.

 

I am sure when both circuits are disconnected the transmission will not go in any gear but, I would like to be certain a short does not exist somewhere else.

 

You have verified that the pressure switch circuit is working correctly and we can eliminate that problem. For the most part, this would also verify the switch is not causing a short back to the shifter as well.

 

So, now I think the focus must go the shifter and the transmission wiring.

I would first inspect the connector plugs to the shifter. Make sure the wires are in the correct location.

 

Check the part number on the shifter and that is the correct one for this machine. If it has had any part number changes, check to see if the change required any other updates to make it work correctly. You can send me the part number you have installed and I can check this too, if you like.

 

Check for electrical interference, confirm that the operation of the horn or window wiper switches does not cause the transmission to change speeds. Perform the following procedure:

1.When a new shifter is installed, ensure that the wire from the horn switch is not wrapped around the wires from the shifter. The horn wire must be routed parallel to the shifter wiring.
2.Park the machine on a level surface. Apply the parking brake. Start the engine.
3.Use the "Auto/Manual" switch to select the manual mode.
4.Apply the service brake. Release the parking brake.
5. Place the shift lever in 4F.
6. Operate the horn.
7.Observe the actual transmission gear display. The actual transmission gear display is located on the monitoring system main module.
8.Operate the front window wipers and the rear window wipers simultaneously.
9.Observe the actual transmission gear display. The actual transmission gear display is located on the monitoring system main module.
10.Repeat Step 4 through Step 7 for 3F, 2F, and 1F. Repeat Step 4 through Step 7 for 3R, 2R, and 1R.
Here is the shifter part number I found from a Service Magazine.
An improved transmission control is now used. This new transmission control features improved immunity from electromagnetic interference.

Adaptable To: The 212-0403 Transmission Control is adaptable to the serial numbers that are listed in Table 1. The 212-0403 Transmission Control is effective with the serial numbers that are listed in Table 2.

 

Table 1
The 212-0403 Transmission Control Is Adaptable to the Serial Numbers Listed Below
Product Group Sales Model Serial Number Range
Integrated Toolcarrier IT38F S/N:6FN1-UP
S/N:5DR1-UP
Wheel Loader 938F S/N:1KM1-UP
S/N:2RM1-UP
S/N:7SN1-UP
S/N:8SM1-UP
950F Series II S/N:4DJ2075-UP
S/N:5SK1-UP
S/N:8TK1-UP
960F S/N:1YM1-UP
S/N:4CL1-UP
S/N:6XL1-UP
S/N:9ZJ1-UP
966F Series II S/N:1SL1-UP
S/N:8BG2048-UP
S/N:9YJ1-UP
970F S/N:7PL1-UP
S/N:7SK1-UP
S/N:9JK1-UP
980F Series II S/N:4RN1-UP
S/N:8JN1-UP
980F S/N:5XJ588-UP

 

Table 2
The 212-0403 Transmission Control Is Effective with the Serial Numbers Listed Below
Product Group Sales Model Serial Number Range
Earthmoving Compactor 815F S/N:1GN1082-UP
816F S/N:5FN629-UP
Wheel Tractor 814F S/N:9DM214-UP
The 212-0403 Transmission Control is a direct replacement for the 201-0213 Transmission Control .

Note: When the 212-0403 Transmission Control is installed as a service replacement for the former 201-0213 Transmission Control, route the horn switch wire parallel to the transmission control wiring. Avoid wrapping the horn wire around the transmission control wiring.

 

Let me know if this is helpful, I am learning from you as well. I have a few medium size F series here but, all the 980's I see are G or H models now.

 

Customer: replied 2 years ago.

Sorry to take so long getting back but I've got alot of other stuff I'm working on and I'm not a computer guy so I've got someone helping me hear. Played with 720 and neutralizer switch wires as suggested and nothing changed and you are correct, when both circuits are disconnected it does not go into gear. Connector plugs to shifter are all good and shifter is original ... no part changes. There is no horn and window wipers had no effect. Tested as you suggested. Looked at your Tables and not sure ... S/N for this 980F is 8JN00527 so it's lower than the 8JN1-UP but is it covered by the 5XJ588-UP listed above? And where would a guy get one of these? I'm ready to try anything cause it's still not fixed.

 

Appreciate your help and not to worry ... we want to pay you either way for your efforts

Expert:  catmastertech replied 2 years ago.

All that means is it covers serial numbers 1 and up. (8JN00001 and up, which we would say all 8JN serial numbers) The 5XJ588 means it will not work for 5XJ00001 through 5XJ00587 serial numbers.

It will work on machines 5XJ00588 and high serial numbers.

212-0403 (shift handle) Transmission Control is still available from CAT. I don't have pricing available to me at this time.

I can only guess the handle has a short that is back feeding through the neutralizer switch to keep enough power in the handle to allow the clutches to engage. (this is why I want to disconnect the switch) This seems impossible though.

 

If your handle does not have the(NNN) NNN-NNNNpart number on it, maybe the new version will fix the problem.

 

Let me know what you find or if you have any other issues on this problem. Thanks.

Customer: replied 2 years ago.

Thanks Donnie. We might try that. Also, there is a used computer for $2700 that Finning will sell us but we can't return it if it's not a computer problem... I'll let the owner decide because I think it could very well be the computer. We had a Finning tech attach a new computer at the beginning of this nightmare but he said nothing changed ...actually I don't think the computer/machine was getting enough power (after I changed the fuses and holders there was a change in the power flow).

 

Anyway, I think we're at the end of our ideas. Thanks alot for your help. When we hit "Accept Answer" can we get back in touch with you to just let you know once the problem is fixed, just FYI without paying again?. Let me know and thanks!

 

Expert:  catmastertech replied 2 years ago.

Well, you have brought up another thing I had not even thought of, the auto-shift ecm.

I am so use to not having auto-shift, I did not consider this machine as having the ecm.

I know the smaller machines only use the ecm to control auto-shift and once you turn off the auto-shift switch, the problems go away. I guess you have tried to run it with the auto-shift off, most operators here won't even turn it on.

This ecm could be different, I have not worked on a 980F and could not say for certain. It appears it could be an issue since, all transmission solenoids are connected to the ecm and not the shift control like on smaller machines.

However, please verify the option code plug is in place and is connected properly for the options this loader has (if any). I have a chart below for the plug, it will be located next to the ecm and should match the wires shown in the chart. I have seen ecms get real stupid when the code plug is wrong.

graphic

I think the link to this question will work after an accept, I have had some replies months after it was closed.

I do want to know if this changes anything.

catmastertech, Technician
Category: Heavy Equipment
Satisfied Customers: 1882
Experience: 19 years Cat, 3 years Case
catmastertech and 2 other Heavy Equipment Specialists are ready to help you
Customer: replied 2 years ago.
Just wanted to let you know that I installed the new computer from Finning and everything works just fine. Should have done it at the beginning! Thanks for all your help!
Expert:  catmastertech replied 2 years ago.

OK, thanks for the update. I would not think the ecm was the fault. I was leaning more to the shift handle. Either way, you have proved to your managers you want to fix any and all issues before ordering an ecm.

He would not be happy to buy an ecm and then find it was a $20 switch.

My thinking is, always start with the cheap parts first.

 

Glad you have it fixed, hope to help you again some other day. Thanks for using Justanswer!

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