CAT Grader 140H

[Blessings A. Harawa]

1 to 4 forward gears and1 to 3 reverse gears have malfunctioned on 140H ....what can be the cause?

 

[Nige]

For those particular gears in the transmsission it means that the Low Range clutch is not working for some reason.
What have you tried so far as regards diagnosing the problem.?
Please post a Serial Number to make tracking down information easier.

 

[koecon]

Any warning lights come on when this is active? Does articulation the machine make it come and go? Those machines are famous for broken wires in the articulation joint. As Nige always says a SN would help greatly!

 

[DColeman]

I have a similar problem (1998 Motorgrader Cat 140H 2ZK03192) will travel in all gears then stops. Wanting to make sure we are putting the right transmission fluid to start out with.

 

[Nige]

Wanting to make sure we are putting the right transmission fluid to start out with.

Cat TDTO SAE30 or any SAE30 oil meeting Cat TO-4 specification.

 

[DColeman]

Cat TDTO SAE30 or any SAE30 oil meeting Cat TO-4 specification.

Thanks for the info and the humor.

 

[LPx]

Hi Team,
I have a 12H CBK01377 doing similar things but the other end of the gears.
i have 1 to 4 but 5 to 8 gets put back into neutral. reverse is similar.
i have gone through the test procedure for the SERV codes and proved continuity in the wiring, insulation tested the wiring (while disconnected from the TX ECU). replaced the suspect solenoid.
the only difference in the fault now is the SERV code 1408.06 is on when the solenoid is plugged in, then 1408.05 is on when it is unplugged (which is correct). the wiring to the solenoid is reading 16.4v dc when the others are at 4.8v (from memory).

My questions for the brains-trust is:
how the hell do i check to see if the ECU is faulty. i know it is unlikely but Cat in Australia seem to have never seen the voltage difference and cannot supply me with a test procedure.
my next course of action to to replace the ECU with a reman and hope for the best.

Any info or tricks would be appreciated.

 

[Nige]

the wiring to the solenoid is reading 16.4v dc when the others are at 4.8v (from memory).

I assume you mean the supply to the High Range solenoid for clutch #8. Is this all the time when the key is on, or when the transmission is in neutral with the engine running, or what.?
More info needed. Can you also confirm the actual voltage numbers that you are seeing.

 

[LPx]

Hi Nige,

ive had to put the machine back in to service . I checked my notebook, the supply voltages are 5.2v to 5.4v on all the other solenoids, 16.4v on solenoid 8. With the machine off and key to on. Transmission in park. I haven’t checked it in any other configuration.

 

[Nige]

Hi Nige,

ive had to put the machine back in to service . I checked my notebook, the supply voltages are 5.2v to 5.4v on all the other solenoids, 16.4v on solenoid 8. With the machine off and key to on. Transmission in park. I haven’t checked it in any other configuration.

I suggest that you need to check voltages on all 8 solenoids both at the solenoid connections and at the ECM end with everything connected (you'll need back probe fittings for your DMM to get into the connector pins) under the following conditions:-
1. Engine on, transmission in park.
2. Engine on, transmission in neutral.
3. Engine on, transmission in all 8 forward and all 6 reverse gears.
To do those tests the best way is to remove the driveshaft.
You'll need a big notebook.............

I can send you an electrical schematic if you don't have one.

Stupid question but I assume that you have already pulled both of the transmission suction screens to inspect for burned clutch material and ruled out a mechanical failure of #8 clutch.?

 

[LPx]

Thanks Nige,

I've got a schematic thanks.
Nothing in the screens. shifts fine every other gear.

when its in the shed next I'll work through your list of checks.
Out of interest, how often do ECM's fail?
The test procedures say it's rare but the Parts department at Cat say the go through a fair few of them.

 

[Nige]

Out of interest, how often do ECM's fail?
The test procedures say it's rare but the Parts department at Cat say the go through a fair few of them.

They don't fail often, but it does happen occasionally.
The problem with that particular ECM Part Number 172-9389 is the fact that it's used on a lot of different machine models (over 1300), simply programmed with different software to suit each application. So the Parts Dept can easily say "we sell a fair few of them" but how ask them how many they sold specifically for grader use.? They probably won't be able to give you that info.

I went through a mare with a 143H recently where we were convinced that the same P/N of ECM was bad so (after a lot of digging & testing) so we replaced it and found that nothing had changed. To be fair though that transmission was not showing a Diagnostic Code for the solenoid like yours.

BTW although those solenoids ostensibly operate on machine voltage it's not specifically the case because the operating voltage for them is generated within the ECM. So it's not unusual to find a significant difference between what's showing from a measurement across the batteries and what you measure at a given transmission solenoid when it is energized.

 

[Nige]

If you don't have access to the service manual this chart shows you what you should expect for energized solenoids in the various gears. Note that #8 solenoid (along with #5 which you may not have considered measuring voltages on because your problem is elsewhere) is energized both in Neutral and in Park.

 

[LPx]

Haven't got that chart thanks mate, that will be handy.
I'll work on over the next couple of weeks and report back, thanks for your help.

 

[Nige]

Haven't got that chart thanks mate, that will be handy.

On the 143H I mentioned earlier we had a "weird" voltage on #8 clutch with the key on, engine stopped, & trans control in park. Changing the ECM did not fix it. We stumbled across that chart later.

When you check the voltage at each of the eight solenoids it will be relatively easy because the power/return wires are right there in front of you. However when you get to the ECM end it's a lot more difficult because the solenoid return wires splice into two common return wires 921 and 922. You can see the splices on the schematic at Grid D-17. In fact thinking about it a splice could potentially be an issue that does not show up using a DMM to simply check resistance but breaks down under applied voltage to the solenoid if you get my drift.
So at the ECM end you measure voltage for solenoids #1, 2, 3, & 8 between wires 752, 754, 751, & 755, and wire 921 (marked "Sol Return") on Pin 7 of connector J1.
For solenoids #4, 5, 6, & 7 the voltage would be measured between wires 900, 902, 901 & 903, and wire 922 (marked "Sol Return 2") on Pin 3 of connector J2.

How many total hours does the machine have on it.?
Has the transmission ever been rebuilt and if so was a new wiring harness (back to that "suspect" splice again because it's buried inside that same harness) fitted to the trans at that time.? TBH for us a transmission rebuild would have a new harness included in the kit of parts for no other reason thatn they get well oil-soaked because of the location.

 

[LPx]

I was looking at the schematic when you replied and found the join at D-17. That is a good point.
Machine has just over 12,000 hours.
The transmission has never been out according to machine records.

When I first had the SERV Codes come up for this issue.

I also had: (which i still tested as per the procedure and proved they were fine.)
081 168.01 - ECM reads voltage at J1-1 below 18v for 2 seconds.
081 668.02
081 669.02
These were not active SERV Codes straight after, they came on then went off in quick succession if you get me.
I used your 'Click box' thread to clear all none active faults and when they disappeared i thought nothing of them.
but thinking now, the voltage change in the solenoid circuit could have given the ECM other faults at the same time. unless the ECM was failing the only other symptom of a voltage change in circuit is resistance change due to a bad connection.

I might go hunting for a splice first i think.

 

[Nige]

I might go hunting for a splice first i think.

I think I'd test the voltages at both the solenoid & ECM end of the #8 clutch and maybe a couple of others (that use the same solenoid return wire) for comparison. If the one with the Code shows a distinct voltage drop between what you measure at the ECM and what you measure at the solenoid then the splice is the obvious place to look.

I'm sorry to tell you but I have no idea exactly where those splices are as regards position in the harness. If you find the problem is actually the splice then a replacement harness is probably the best long-term solution, probably as part of a transmission rebuild bearing in mind the hours. The one that's on there is 16 years old and has probably seen better days.

 

[GETNET]

H

I have a similar problem (1998 Motorgrader Cat 140H 2ZK03192) will travel in all gears then stops. Wanting to make sure we are putting the right transmission fluid to start out with.

Hi sir, i faced also the some problem like this..what i do please help me?

 

[Nige]

Hi sir, i faced also the some problem like this..what i do please help me?

When I look back through this thread it is already dealing with three different machines and has become very confused as a result.

I suggest that you should create a new thread in the Graders section. This link will take you through the process - https://www.heavyequipmentforums.co...estions-answered-hopefully.76199/#post-801587

In your first post please include the following information.
1. Machine model and Serial Number.
2. Since this appears to be a transmission problem mention the hourmeter reading and if the transmission been removed and repaired before.
3. A brief description of the problem symptoms.
4. A description of what you have done to try to diagnose/fix the problem so far.