1986 cat D4h

cfisher05 · Aug 28, 2022

I have a 86 cat D4h serial number 9db00424, the light come on in lower right hand corner , so I changed the power train oil filter with part # 343-4464 turned key on everything was fine started up let run and check transmission fluid at operating temperature everything was good, started to push dirt for roughly 10 mins and the light started flashing so I shut the dozer down waited 30 min turned the key back on and light went out started up ran for awhile still fine , start pushing dirt same thing happens
Any ideas where to go from here to fix problem, in an older post someone has mentioned a stuck plunger or worn spring but not sure where to find that , didn’t see it when I changed the filter but may have missed it

Nige · Aug 28, 2022

I'll find you some info on the filter bypass valve/plunger, but meantime ........
1. What type & viscosity of oil are you using in the transmission.?
2. When is the last time the oil was changed and the magnetic suction screen was cleaned/inspected for debris and metal particles.?

The oil filter bypass valve is on Page 3 of the attachment. The spring and spool are Ref #2 & 3.

cfisher05 · Aug 28, 2022

The tractor is new to me so I’m not sure last time changed when I added after changed filter I used cat to4 which ended up being 2 qts roughly from the oil in the filter it self , I pulled it out a couple times to inspect it be4 changing

Nige · Aug 28, 2022

cfisher05 said:
The tractor is new to me so I’m not sure last time changed

In that case I would suggest your first move should be to drain the oil and pull the screens for inspection. Take photos of whatever you find.

Do you still have the old filter you removed.?

cfisher05 · Aug 28, 2022

Yes still have the old filter, it had part number 1r-0719 I didn’t know if that would be any indication of when it was changed last, just wondering if that was the original part # or how long ago cat updated to that new part #

Nige · Aug 28, 2022

cfisher05 said:
Yes still have the old filter, it had part number 1r-0719 I didn’t know if that would be any indication of when it was changed last, just wondering if that was the original part # or how long ago cat updated to that new part #

The Part Number was updated a while ago, but the reason I asked you the question is to have you cut the old filter open and look for particles in the bottom of the filter media pleats. I know this video is for an engine oil filter but the process is the same, and you don't necessarily need the cutting tool to get the filter apart. The particles you are looking for will not be metallic but look like black specks of burned carbon. Cut it open and report back what you find with photos.

D5Dan · Aug 28, 2022

Adept Apes filter cutter is bada$$…but for the few filters I cut in a year, this summit racing one has done me well. They do offer a blade/cutter replacement too.

Cutter-
https://www.summitracing.com/parts/sum-900511

Blade replacement-
https://www.summitracing.com/parts/sum-900511-1

Good luck, and don’t forget to post some pics of what you see/find- impressive what this group will warn you of (and typically very accurate!)

cfisher05 · Aug 28, 2022

These are pics of what I found on the filter

Nige · Aug 28, 2022

Without knowing how long that filter had been in operation it's hard to tell whether what's on it in a couple of places is excessive. Drain oil and inspect the magnetic suction screen is the next step.
At the same time pull the bypass spool, inspect the spool for wear, and check the spring. It should measure 1.86" (47.2mm) free length.
You said you were using Cat TO-4 oil. What viscosity.?

cfisher05 · Aug 28, 2022

Are you meaning drain the oil in the filter housing or drain the whole system, the spring is really close to the 1.86” what is the tolerance cause I don’t have anything to measure that precise, the spool has some wear on the inside , looks like where the spring moves inside it
Sae 30
Not sure if you can actually tell anything from pics

cfisher05 · Aug 28, 2022

Just out of curiosity which sensor controls the plugged filter warning and what does the other one tell you? Is there a light for it on the ems

Nige · Aug 28, 2022

cfisher05 said:
Are you meaning drain the oil in the filtered housing or drain the whole system

It will be necessary to drain the whole system in order to remove the magnetic screen from the suction side of the transmission, especially if you have no idea when the screen was last removed. If you have clean containers to drain the oil into there is no reason why you can't use it again. The screen is #34 on the attachment.

cfisher05 said:
Just out of curiosity which sensor controls the plugged filter warning and what does the other one tell you? Is there a light for it on the ems

The transmission temperature sender has a single wire 443 Yellow connected to it. That is the sender responsible for the bottom LH warning light on the EMS for transmission temperature.
The plugged filter switch has the two wires 424 Grey and 201 Black and operates the bottom RH warning lamp. I've included a snip from the electrical schematic below.

cfisher05 · Aug 28, 2022

My bottom Lh says hydraulic oil temp
Top rh says power train oil temp and bottom Rh says power train filter is that correct
So just so I am getting this right cause at this point I’m not sure I trust the wiring, the one that has the spool and spring inside is what controls power train filter light and the temp sender with the one wire that’s on the right of filter housing when sitting at operator station controls transmission temp
Sorry this is starting to get a little frustrating

Nige · Aug 28, 2022

cfisher05 said:
My bottom Lh says hydraulic oil temp
Top rh says power train oil temp and bottom Rh says power train filter is that correct

Yes that is correct.
My apologies I misread the bottom LH from the manual as the transmission oil temperature warning. That is not the case.

cfisher05 said:
So just so I am getting this right cause at this point I’m not sure I trust the wiring, the one that has the spool and spring inside is what controls power train filter light and the temp sender with the one wire that’s on the right of filter housing when sitting at operator station controls transmission temp

If everything is connected properly that is how it's supposed to work.

cfisher05 · Aug 28, 2022

So at this point I think it’s a wiring issue , there’s no yellow wire here and someone split the black and grey wires and ran to the temp sender and the plugged filter switch
Is there only one yellow on the temp sender cause it runs down to another temp sensor that has a ground

Nige · Aug 28, 2022

The best thing I can do is to send you the electrical schematic. Keep an eye on your PMs.

1986 cat D4h

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