P500 Pioneer 500 rear differential


May 22, 2020

  1. 500
I am looking into two issues my Pioneer 500 has. First is rear differential gear whine, the second is metallic looking rear diff fluid.

The 500 has had both issues since day one of my ownership with 26 miles on it.. I changed all the fluids same day I brought it home just like every "new to me" toy that I get. I found that the rear diff fluid had a metallic look to it. From forums I have read this is termed "Honda Gold" and to some is normal and don't worry about it. The front diff looked clear (clear meaning no metallic look) as well as the engine oil. I have been changing the rear diff every 50-75 miles since. Unit now has 600+ miles. Just drained it the other day and it looks the same as it has been.

It was mentioned to me the rear diff may need shimmed. I studied the service manual and decided to check what I can without removing the rear differential from the 500.

I checked the gear pattern first and to me it looks close compared to the service manual "pictures." I will attach pictures though not the best.

I then checked the backlash per the service manual procedure, three readings 120 degrees apart. Here they are..008,.008,.013. I did it once more,008,.010,.015 and again for fun,.009,.015,.008. Specs are .002-.007,service limit is .020. Measurements are in inches. I will attach pictures.

The "Gold" dust doesn't seem to be attracted to a magnet so I guess it is not steel. It looks like ,well, gold dust about the same amount each time I change it. I am including some pictures for keen eyes to see.

Has anyone been to this point? First pic is Honda gold.


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