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Got a very strange noise. Gearbox just been rebuilt with a new casing ( 4 synchro remote, helical) after the idler gear destroyed itself and the end cover. The car now starts and runs fine, no noise or lack of when you dip the clutch, selects gears lovely when on the move but there is a what i can only describe as a whiirrring come whine that increases with speed. BUT it is only there when you are accelerating, not when you lift off ( even slightly) Jim at RACE has never heard anything loke it and he's probably heard most! ANYONE??

Do you have anything from minisport in there ????

have you properly shimmed up the idler gear?its probably eating into the casing as we speak

or a faulty idler gear bearing.........
it will sound like reverse in all 4 gears ,,probably much quierter than the intermediates in top

usually chatter on idle gives idler gear issues away..

had the same though with sombody missing with diff bearing shims after messing with a gearbox too

its not the worng idler is it like a 1275 on a 998

Have you replaced any of the gears?
If you have, it may be 'gear whine', as they are not matched to each other?

If you think you have a problem the chances are you have a problem, can you afford to ignore it, if it goes bang you will have a much bigger bill than if you pull it out and check.

If it were me I would pull the motor out and double check.

Having said all that I just had a thought, when you accelerate does the engine move enough for part of the engine to touch the subframe or shell somewhere, this will transmit engine noises that would not normally be heard straight through into the cab which will sound very odd, worth a look.

Pete

I had something similar about 20 years ago. I bought a 'S' conversion kit for close ratio helical gears for pre-A+ 4-synchro box from MiniSport which was the input gear and laygear (all helical, 18 tooth input and the 1040 laygear).

When fitted these worked well for about 500 miles but then developed a very loud whine when accelerating, almost like having straight-cut gears.

Took it apart just in time... The input gear spline had been cut too small, the bottom transfer gear was rattling around and starting to unwind the nut etc... Much longer and it would probably have escaped through the transfer casing.

Complained to Minisport, no resolution whatsoever (seems to be a theme here). Have not bought anything from Minisport since.

sounds nearly as good as minisport duplex timing gear sets,,
timing wheels made from caramel