Issue with 1/8 conversion....possible motor problem

[padailey]

ok I hope I have enough info to make a decent diagnosis.

Last time I raced my hyper 7 conversion (MM - Feigao 9XL) when I would get on the power I would get a very high pitched squeal like metal scraping together. Plenty loud because I could hear it on the track over 10 other nitros. Also it just did not have much power. At first I thought it was the diff and that maybe I had it shimmed to loose and the gear was slipping out of the pin (hope that makes sense). I took the motor out of the buggy and ran it... it starts to get a little high pitched whine to it at about half throttle. Enough that I'm scared to push it much further. Could that be a sign of a bad bearing? Eyeballing it they look ok. I thought also maybe that the pinion was slipping. Not sure it would make that much noise and it seems plenty stuck. It had slipped at one point and made a small grove on the motor shaft but didn't make the kind of noise I'm getting now. Any thoughts or suggestions to try?