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D6N head scratcher

TVA

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Well! Showed up there just to meet the guy with scanner, he said at pedal fully released it shows 54%. Scan tool says it supposed to be 17%. Took the sensor off, started messing with it with flat head screw driver, and long behold - it is releasing at 17%!
But there’s no adjustment slots in that darned thing!
Anyway! Picking up sensor tomorrow from the dock after night delivery.
 

TVA

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According to the troubleshooting procedure the sensor should be around 5% duty cycle at pedal up and 95% at pedal fully depressed. Where did the 17% number come from.?
Cheap Can-Do Chinese scanner.
The values might be screwed, but one thing certain - that sensor is way out of wack, and needs to be replaced.

And tell you honestly - I am glad that I wasn’t the one who had to make difficult $500 call. He condemned it - he will be responsible if turns out he was wrong.
I wish the owner used that guy from get go, because I am swamped with my work, like crazy blind ox! Only messed with it because owner is my very good customer, and it was hard to say no.
But that guy is not a tech, he just works at construction company, and they have bunch of CAT equipment, so they bought cheap scanner with On-Highway and CAT software.
Today is Thanksgiving eve, so he got off work early and made the test.
 
Last edited:

TVA

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Since I don’t have any scanner, I might look in to this CanDo OHV Pro.
That thing slow as hell, but at least it is reading something. Better then nothing, don’t have much work that requires something better yet.
 

TVA

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So, as far as I understand the new sensor will need to be calibrated. And from what I read one needs to have at least 4C-8195, to do that.
Or can it be done without any special tools?
 

TVA

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According to the troubleshooting procedure the sensor should be around 5% duty cycle at pedal up and 95% at pedal fully depressed. Where did the 17% number come from.?
The sensor installed is not at its own lower stop, pedals shaft with slot is slightly elevate it, so probably that’s where 17% came from.
5% is probably sensors lower threshold not installed.
And this what I stumbled across:

F3C21E73-B7F6-4C26-AAEA-E2B73FE1724F.jpeg
 

TVA

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Anyway, mister Nigel!
It was nice introduction to dozers for me! And one helluva teaching performance on your part!!!
Thank you very much!!!

Steering and blade was absolutely no brained for me, because that’s a stuff I deal with almost every day ( Rexroth A10VO, A10VG and A2FE), together with LS controls. And this machine has mechanical linkage blade control and not pilot.
3126 is somewhat familiar engine also.
Had basic knowledge of Power Shift transmissions ( even rebuild couple of Clarks in my younger years).
But transmission controls was total new deal to me!
Thanks again for your help!!!
 

TVA

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So, as far as I understand the new sensor will need to be calibrated. And from what I read one needs to have at least 4C-8195, to do that.
Or can it be done without any special tools?
Clickity - click -click!!! :D
Now I know what mister Nigel dedicated the famous thread to!
 

Mobiltech

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Well! Showed up there just to meet the guy with scanner, he said at pedal fully released it shows 54%. Scan tool says it supposed to be 17%. Took the sensor off, started messing with it with flat head screw driver, and long behold - it is releasing at 17%!
But there’s no adjustment slots in that darned thing!
Anyway! Picking up sensor tomorrow from the dock after night delivery.


So this thing has been driving with the brakes half applied for a while. I would bet the brakes are fried and that’s why they don’t fully apply when it hits the secondary switch.
 

TVA

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So this thing has been driving with the brakes half applied for a while. I would bet the brakes are fried and that’s why they don’t fully apply when it hits the secondary switch.
It was intermittent problem, and neither operator or me was giving it a gas when it happened. Operator said that it should pretty much start to go on idle. So when it didn’t happen we did not force the machine, or we could feel it had resistance.
The guy that showed up with scanner, he did forced machine to drive by releasing decelerator fully, and you could tell it was struggling. But he was not there too many times, I think only two times.
 

Mobiltech

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Ok. I was just going by the fact that they walked it a quarter mile just before it happened and you had smoke or steam showing up.
Now you said the brakes don’t lock when fully applied.
Most operators I know say that just happened now!
 

TVA

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Ok. I was just going by the fact that they walked it a quarter mile just before it happened and you had smoke or steam showing up.
Now you said the brakes don’t lock when fully applied.
They said it was walking fine. The problem started the next morning.
Walking was done by someone else, not the regular operator ( he was at his chemotherapy at that time), another thing is the regular operator said that he never touched the brake pedal before, as we don’t really have hills around here ( that’s why we have problems with flooding). So the other guy who was walking it - might have operated the brake pedal and that’s when problems started.

The smoke was coming out from TC area, but after we put 20 gallons of oil in the transmission, I didn’t see it again. That’s another goofy thing, even after adding that expensive dye to the oil - I still can’t read level when using regular dipstick tube. When using filler neck, it seems to show little bit overfilled at engine idling. I still think we might have TC scavenging problems, but brakes take priority.
 

TVA

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Update:
Installed new sensor, and as was expected - the machine did not started to move. Just with the new sensor it doesn’t flash “serv. code” and brake lamp every other time when switching to forward or reverse. And the same almost every time brake pedal gets depressed and let go.
Only occasionally on brake pedal full swing movements.

Talked to the owner, told him either set appointment with CAT for calibration, or if he wasn’t me - I will build the clicker box and try to do that myself.

He said that for CAT it’ll be around $1000 just to come out, they will come up with any fee they can imagine to charge at least that.

So I guess I am going to get busy building clicker box. And start looking for calibration instructions. And read them very carefully - so I will not screw up.
 

TVA

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Another update:
The guy with the scanner came in and calibrated the sensor with his cheap Chinese tool.
Dozer worked for about 1 1/2 hours and started leaking from belly pan, that under cab. I guess we are finally getting our transmission oil level question answered.

Who thinks it is scavenging problems?
 

TVA

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Sorry! Forgot to do update in timely manner.

The leak wasn’t transmission, but implement pump discharge hose burst, due to blisters in rubber.
Although torque converter is all wet on top, but owner just wanted quick fix and back to work.
 

TVA

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Yeah! That thing is a huge mess!!!
Bunch of hoses in steering system have blisters in them and rub on each other.
Spaghetti lines are cracking and two of them leaking.

Almost all the harness pigtails have insulation coming off of the wires as soon as you touch them.
Drive line is the “cleanest” part out off the whole cluster and constantly dripping oil for 5 days straight now, looks like I was right about scavenging problems and overfilling of the transmission. And looks like both seals are blown.

Suction hose for charge and converter-cooler pump looking all mushy and kinked. The transmission breather was buried under at least 1” of crusty dirt (besides neglect - I blame CATs stupidity of not insulating A/C low pressure/return lines, which was sweating continuously, mixing with dust and making mud).
Although there was supposed to be some kind of case pressure relief through dipstick tube.
Torque Converter looks all covered in oil.

Had a long and hard talk with the owner, he wants it fixed good now, after a few times it was “fixed” just to have another problem come up.
Getting quotes for some of the smaller harnesses to see if it will be feasible to buy them VS re pin and splice.

The only problem - I don’t know when I am going to do all of this! I am swamped with other work, and owner is hell bent on me doing the work, because I am “an anal stickler”!!! :D

13CF7C3A-B5EB-4973-8E0B-86BDCC19BBF1.jpeg 60B8F15E-649F-4C46-9FDC-6C138F1798E9.jpeg BF72197B-8F89-4875-A5D9-78244C450F97.jpeg
 

TVA

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Yeah! That thing is a huge mess!!!
Bunch of hoses in steering system have blisters in them and rub on each other.
Spaghetti lines are cracking and two of them leaking.

Almost all the harness pigtails have insulation coming off of the wires as soon as you touch them.
Drive line is the “cleanest” part out off the whole cluster and constantly dripping oil for 5 days straight now, looks like I was right about scavenging problems and overfilling of the transmission. And looks like both seals are blown.

Suction hose for charge and converter-cooler pump looking all mushy and kinked. The transmission breather was buried under at least 1” of crusty dirt (besides neglect - I blame CATs stupidity of not insulating A/C low pressure/return lines, which was sweating continuously, mixing with dust and making mud).
Although there was supposed to be some kind of case pressure relief through dipstick tube.
Torque Converter looks all covered in oil.

Had a long and hard talk with the owner, he wants it fixed good now, after a few times it was “fixed” just to have another problem come up.
Getting quotes for some of the smaller harnesses to see if it will be feasible to buy them VS re pin and splice.

The only problem - I don’t know when I am going to do all of this! I am swamped with other work, and owner is hell bent on me doing the work, because I am “an anal stickler”!!! :D

View attachment 249798 View attachment 249799 View attachment 249800
I think I screwed up on the breather though! :D
There’s something that looks like breather on top of the return manifold - but I cleaned it up more today - and it is solid piece of casting.
 

TVA

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I’ve also jumped to conclusions too quick on the A/C lines ( I apologize - CAT) :rolleyes: :(!!!
After further cleaning I discovered that those are winch/ripper lines. Which is probably even worse, because it is the wettest part of the top of the transmission!
Now I have to worry about leaks out of there also, like I didn’t have enough to worry about before. :(
 

TVA

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And now I would have to re seal the blade control valve ( spool seals leaking) and brake solenoid block. Great!
 
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