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On my last shut down my first bearing in my TR drive shaft was making a noise at the same point in rotation during coast down. I tried loosening the mounting bolts and repositioning but when I torque it down it continues to make the noise. Someone told me it could be a side load. Should I fly a bit and check it or is it failing and I should replace it? Thanks for any advice.
Nick
Location: Wasilla, Alaska
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any chance this bearing is serviceable with grease? and if you can get to it to service it, can it be removed and replaced as easily? cost of the bearing?
if you can do another ground run at 100% for 5 minutes and shutdown, check the bearing temp?
Location: West Plains Missouri
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Geno Mancini has done a lot with tail rotor shafts and bearings. Perhaps he has some insight.
Location: Minnesota
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Would you take a picture of it.
If it's warmer than the others, change it, and/or change them all.
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07-15-2026, 10:09 AM
(Edited 07-15-2026, 10:10 AM by Homer Bell.)
It could be rocking on the shaft, not the bearing failing, just not tight on the shaft. If that’s the case you might not see any heat buildup. Trouble with that is , the shaft is probably being worn down and might eventually fail. Most bearings should be Lock Tited on installation to prevent this from happening. Long driveshafts and harmonics can be an engineering nightmare. Look at the way the tail drive shaft is mounted in the R22, pretty interesting design. But over-speeding the rotor system in these ships with drive shafts is a big no no, don’t do that. However in a RW with belts, 120%, no harm done, very forgiving.
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120% of 520 is 624.
When my governor failed at Jims back in Oct 2023, my rotor rpm went to 604 for a few seconds.
That bowed the 5 - 5/16" blade strap bolts .003", which I replaced.
BTW, thanks Sharon, for giving me a ride back to my trailer.
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I went ahead and replaced the bearing and found a little corrosion underneath it. Flew it for an hour yesterday and there was no more noise. Onto the next issue 🤦♂️😂
Location: Wasilla, Alaska
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thanks for letting us know the resolution! i'm sure this will help someone in a similar situation down the line make a good decision aswell!
👍
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It is really helpful for everyone that is finding solutions to issues posts them here on this forum so that others can later refer to the posts. Facebook postings disappear with time but if we keep this forum active it will stay here for all of us.