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Scott Gardner Job title Gold Diagnostic Technician Place of work Porsche Centre Bournemouth, UK Time at Porsche 12 years
How reliable is the 915 gearbox? I’ve heard the G50 is the more desirable gearbox for 3.2 Carreras, but surely the 915 isn’t that bad? What should I look out for, and if it’s in need of a rebuild what are the likely costs I can expect to have to pay? I await your wisdom on the matter…
Geoff Cheetham, Manchester
Well the good news is both gearboxes are great gearboxes. Both five-speed, reverse in the 915 is situated ‘down and right’ from neutral, the G50’s backwards ratio found by shifting ‘up and left’. In terms of tangible differences otherwise, the G50 has a hydraulic clutch which can be easier to live with for stop-and-go traffic, whereas a 915 gearbox is cable operated.
With regards to costs for rebuilding a 915, they can vary depending on where you have it rebuilt and the condition of the gearbox. If you are having a full overhaul on the ‘box you can expect it to run into the thousands.
Personally I don’t have much experience with either gearbox so it’d be unfair for me to pass personal judgement. The last gearbox I rebuilt was a G86.20 from a Boxster, but I have never stripped or rebuilt a classic G50 or 915.
Like anything, you can read many horror stories about them if you research enough. However, like you say, they can’t be that bad. Do yourself a favour and buy a car with a good gearbox from the outset: check the transmission engages easily enough on your test drive, and be wary of any sloppiness in the shifter. We’ve said it many times on these pages before, but a bad 915 gearbox can totally detract from the experience of driving a classic 911 and, with enough good examples out there, there’s no reason for you to buy a 911 with a knackered transmission.