Komatsu WA480-5H transmission issue

Hello, we have acquired a used Komatsu as per below:
WA480-5H 2002 year
27,000 hours
no available service or component history
Problem: the transmission is fitted with a very very fine gauze filter which blocks up and prevents the machine from driving. When filter is replaced ($500 a go) it lasts about 10 hours and blocks again.
If you remove it, it runs perfectly.
We have had trans oil analysis done and it comes back clear. Changed the oil and filters, same result.
Put an old filter in some phosphoric acid and it fizzes. The filter and the material that blocks it is so fine you cant actuall get a sample out of it.
We suspect this may have been a long term issue with the previous owners, judging by the amout of wear on the related filter housing threads.
It had worked in a quarry.

Any suggestions about the next move would be appreciated.
thanks Michael.

That acid test kind of sounds like aluminum in the oil. What kind of oil analysis are you doing? When your machine does run, is there any indication of the transmission overheating?

John C. said:

That acid test kind of sounds like aluminum in the oil. What kind of oil analysis are you doing? When your machine does run, is there any indication of the transmission overheating?

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Thanks for your response John,
the oil sampling, done through Komatsu dealer, showed no contamination. The machine has been worked since we have owned it, but not a really hard application ; there has been no evidence of transmission getting hot.
We are wondering if there could be some fine contamination from the quarry dust where it worked ( we think it was a blue metal/basalt quarry) but thought this should have shown in the oil sample.

Can you post the SOS report Nige might be able to look at it and give you an idea what's happening
I find it a bit hard to accept that you have a plugged filter and the SOS shows no evidence of what is in there
Mark

Mark250 said:

Can you post the SOS report Nige might be able to look at it and give you an idea what's happening
I find it a bit hard to accept that you have a plugged filter and the SOS shows no evidence of what is in there
Mark

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Hello Mark,
thank you for your interest.
on inspection of the report myself, it appears their are some issues of contamination, I'll be very interested in what action you or others reccomend once you look at the report. I have attached the SOS report pdf. thanks for your assistance, cheers Michael.

The report shows high copper but none of the other readings that might be associated with it. I'm thinking along the lines of a sensor going bad or a wiring harness issue at this point. Komatsu likes lots of electrical stuff with all the associated components within. Springs in switches get weak over time.