Jon J 1250 Posted December 8, 2021 Report Share Posted December 8, 2021 Hi, My 12/50 is just back on the road after a 16 year rest. In my ownership It has always had a kind of hissing/scraping noise from the gearbox when accelerating in 3rd gear, you do accelerate through it, but probably shouldn't be there. The car has done 50k miles 20k of which I have covered since 1995, and is the original gearbox from 1965, Does anyone have an idea what is causing the noise, is it a common thing? Regards Jon Link to comment Share on other sites More sharing options...
johny Posted December 8, 2021 Report Share Posted December 8, 2021 Hi, obviously youve changed the gearbox oil and got the correct quantity and quality in it? The other thing is does it stop if you hold the gearlever? Link to comment Share on other sites More sharing options...
PeteH Posted December 8, 2021 Report Share Posted December 8, 2021 Could it be harmonics?. Something which only "vibrates" at certain frequencies? Pete Link to comment Share on other sites More sharing options...
Pete Lewis Posted December 8, 2021 Report Share Posted December 8, 2021 sounds like you have a distorted selector fork as the pads normally run in the clearance of the sleeve but if a bit bent the pads foul on the sleeve and make a singing scraping noise does loading the gearstick make some change to the noise this is generally called sizzle any other gear selection happenings ???? Pete Link to comment Share on other sites More sharing options...
Peter Truman Posted December 8, 2021 Report Share Posted December 8, 2021 My sons second car was an Alfa 33 great little car, but I had to get the gearbox rebuilt, Just Alfa here showed me the selector forks he had to replace they were worn past the wear pads, he stated it's an Alfa thing, the Alfa driver has to hold the gearstick at all times between changes so it goes faster and wears the selectors out, trying to break my 19yr old son from the Alfa habit was nigh on impossible, great little car but it did consume starter motors! Link to comment Share on other sites More sharing options...
Colin Lindsay Posted December 9, 2021 Report Share Posted December 9, 2021 My 948 Coupe gearlever actually rang like a bell when it got to about 70, I have a brrrriiinnnggggg doorbell that sounds exactly the same. Link to comment Share on other sites More sharing options...
Jon J 1250 Posted December 9, 2021 Author Report Share Posted December 9, 2021 Sizzle is quite a good description of it actually. I will have to see if putting pressure in different directions on the gear lever makes any difference. Interestingly it doesn't always do it, but mostly does. Changing the oil is after several decades, is probably a good idea too. It had a new gearbox extension rear seal in 1988, and that's probably the last time the oil was changed. Link to comment Share on other sites More sharing options...
johny Posted December 9, 2021 Report Share Posted December 9, 2021 The good news is that, if this is the 'standard' sizzle that many of these gearboxes make, it can be cured by overhauling the gear lever mechanism with a cheap kit and this can be done with the gearbox in place but just the cover over it removed👍 Link to comment Share on other sites More sharing options...
Pete Lewis Posted December 9, 2021 Report Share Posted December 9, 2021 im sure the nasty plastic cup washer and spherical ball on the gearstick was changed from metal to plastic as a sizzle solver many years back Pete Link to comment Share on other sites More sharing options...
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