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Cat 725 E329 code

Hunter013

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S/N: B1L01417

Code E329 trans filter plugged. I changed the filter and bypass switch. No change. The filter didn’t have any debris in it and the oil looked fine. What else is there to check?
 

Nige

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What you have is not a Diagnostic Code, it is an Event. It's important to understand the difference.
A Diagnostic Code occurs when a sensor/sender/switch that is desigend to monitor a particular parameter or similar malfunctions.
An Event occurs when the diagnostic system is working fine but a parameter goes outside of the expected/desired range. As in this case the plugged filter switch is closing due to back pressure in the filter.
I changed the filter and bypass switch. No change.
Which bypass switch did you change.? I see two bypass switches on that filter head.
What oil are you using in that system.?
Are you using a Cat filter.? What Part Number.?
Did you squeeze the filter media in a vice to remove all the oil before inspecting for particles.?
Are you doing oil analysis.?
Is the transmission temperature gauge working correctly.? The E329 Event is temperature-dependent on that sensor.
 

Hunter013

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391-7125 is the switch I changed. It's located on the transmission housing just above the filter.

We use TO4-30 oil in the trans.

Originally, we had a Cat 139-1536 filter in there. When I recently changed it, I put in a Baldwin PT83.

I have not yet inspected the filter for particles.

Negative on the oil analysis

I switched the temp sensor with a known good one and verified it was correct.
 

Nige

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I have not yet inspected the filter for particles.
That would be the first thing I'd suggest to do. Generally from a visual external inspection you won't see much unless there has been a catastrophic failure. The filter needs to be cut open in order to remove a section of the media which can then be compressed in a vice before being opened out to inspect the bottom of the pleats for the presence of any particles.
I don't know if you are familiar with the process but there is a good filter cutting/inspection video on YouTube produced by a Cat dealer tech who goes by the name of "Adept Ape".

I've been doing a bit of digging and the filter element in that location is apparently extremely sensitive to what we'd call "resistance to flow" which is what moves the spool in the valve in the filter head and ultimately sets off the alarm. I would suggest initially to revert back to an OEM 139-1536 element and see what happens.

Was the plugged filter alarm activating before you switched from an OEM to a Baldwin filter.?

Can I also suggest that you remove the switch again and pull out the bypass spool #1 that operates it. Check that the spacer #8 (15mm diameter x 3mm thick) is not missing. Check the spring #4, it should have a free length of 35.5mm with an outside diameter of 17mm. If you put a 1 pound test load on the spring it should compress to a length of 23mm.

1684790289267.png
 

Hunter013

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I cut the filter open and I couldn't see any shavings or particles. We put a Cat filter back in it and it threw the code right away again. The code would come on and off for the past couple months, but now it is staying on. We took the switch out and all the internals seemed correct.
 

Nige

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I switched the temp sensor with a known good one and verified it was correct.
Sorry I didn't ask this before. Which sensor did you swap it with.? There are a few different ones on the machine. Also have you tried running the machine longer until it gets up to temperature.?

It would not be unusual for the filter bypass switch contacts to close with cold oil. That's the reason for the temperature dependency. If the oil temperature signal being sent to the ECM indicates below 60 DegC the alarm will not sound even if the filter goes into bypass.
We put a Cat filter back in it and it threw the code right away again.
Therefore if your alarm is going off immediately when you start the machine from cold my first thought is that something is wrong with the signal from the temperature sensor.
We took the switch out and all the internals seemed correct.
Just to tick the box. Was the spacer behind the spring present and correct.?

Next step we might have to get into diagnostics of the electronics. IIRC you have ET don't you.?
 

Hunter013

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I swapped the sensor with a sister 725's trans temp sensor.

The alarm won't turn on until, I think, 124 DegF. I accidently left it idling for maybe 30 minutes and the alarm was still on.

The spacer was present and the spring was correct.

I do have ET.
 

Hunter013

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I have not checked. If I'm seeing SIS right, the test port should be right next to the bypass switch and be these pressure?
25​
Pressure At The Transmission Pump (High Idle)​
1790 ± 140 kPa (260 ± 20 psi)​
25​
Pressure At The Transmission Pump (Low Idle)​
1655 ± 140 kPa (240 ± 20 psi)​
 

Nige

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In that case I’ve got nothing.

The only other thing I would try if it was mine, just for a short test, would be putting an additional spacer the same thickness as the original between the spring and the bypass spool but that is a decision you have to make for yourself. And it would only be for a test, not with the intention of leaving it in there.
 

Hunter013

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Noted. I saw that the trans solenoid #5 current percentage stayed at 83.9% in neutral at low idle and it didn’t change when I put it in gear. Idk if that’s normal or not.
 

Nige

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Noted. I saw that the trans solenoid #5 current percentage stayed at 83.9% in neutral at low idle and it didn’t change when I put it in gear. Idk if that’s normal or not.
Take a look in SIS for what clutches are engaged in which gears. There will be one clutch engaged in neutral, usually #4 or #5.

Not sure if there is a calibration procedure for the clutches in that transmission. It’s an ICM tranny so there ought to be. A new calibration wouldn’t go amiss under the circumstances.

The 139-1536 is a high efficiency element. I’m going to have a look to see if there is an element of identical size with a different micron rating that might not create so much back pressure.

Also I strongly suggest that you pull an oil sample and have it analysed, especially for ISO Cleanliness Code. The analysis cost is probably less than the price of an oil filter and it can potentially tell you a lot.
 

Hunter013

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I’ll take a look at sis. Even with the engine off key on, #5 shows 83.9%.

The only calibrations shown for the trans are trans fill and retarder performance.

I had a sample sent out the day this came into the shop, just waiting for results.
 

Nige

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The only calibrations shown for the trans are trans fill and retarder performance.
The clutch fill calibrations are the ones you should be interested in. Each clutch will be calibrated individually.
Even with the engine off key on, #5 shows 83.9%.
That wouldn’t surprise me. The electronically-controlled transmissions often work that way.
 

Nige

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The 139-1536 is a high efficiency element. I’m going to have a look to see if there is an element of identical size with a different micron rating that might not create so much back pressure.
Try a 1R-0722. It's not so fine a micron-rating as the 139-1536 (33 micron vs 6). It won't do any harm in the short term.

If changing the Part Number of the element turns off the plugged filter alarm I have a strong suspicion that the Particle Count when your oil sample analysis results finally arrive is going to be in the stratosphere, especially for the smaller particles up to 6 microns in size.
 

Nige

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I cut the filter open and I couldn't see any shavings or particles.
You did use a vice to squeeze the oil out of the section of filter media that you cut out of the filter element I hope.? See this video - Filter Inspection

Did you by any chance run a magnet over the surface of the filter media just to see if it picked anything up.?

I was out for a walk this evening and turning this issue over & over in my head. I can't get away from the suspicion that you have a clutch (or clutches) starting to come apart. A transmission fill calibration ought to be a good indicator.
 
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