crazyrx7

I had my tranny rebuilt last March with all brand new bearings, synchros, 1st and 3rd gear and a hub. At the same time I also install a light weight flywheel and a stage 3 clutch. Anyway the problem is when you gear down from 4th to 3rd gear the tranny makes a whining noise like an alternator noise through the stereo.

It only happens when gearing down in the first 3 gears. Gearing down from 5th to 4th there is no noise but as soon as I gear down from 4th to 3rd the noise appears. The noise never happens on acceleration only on deceleration. If I'm rolling in neutral the noise isn't there but as soon as I engage a gear then the noise appears.

I tried changing the tranny fluid but the noise is still there. The mechanic opened the inspection plate and found nothing wrong. All of the gears looked perfect with no unusual metal shavings in the oil.

Can anyone point me in the right direction?


R.K.

dhahlen

iTrader: (5)

I've driven several cars, and when I downshift it makes that noise. Not quite as high pitch as alternator hum, but it's still audible. It is most likely from the engine slowing itself down. If you had the tranny inspected, I wouldn't worry about it. It may be new parts wearing in, or the flywheel/clutch setup. I have an ACT 6 puck with a racing beat light flywheel and I get them hum and I know my tranny doesn't have any problems at all.

I'd start to worry if it was a grinding noise.

dgeesaman

iTrader: (7)

Sounds like the countershaft spinning up. If you hear this noise as you engage the lower gear, with the clutch in, then that's what's happening - the synchros are using friction to match the speeds. You can double-clutch and neutral blip to avoid the c-shaft having to spin up/down.

Without hearing the noise myself (and I'm not sure what a dying alternator sounds like), it's hard to say. Probably just a slightly noisy bearing, and nothing to worry about.

Dave