Reducing play in gearshift mechanism

[Porboxs]

My S shift is fairly indistinct and I’d like to refresh it. Mind you I had a new Boxster (not the one I have now) and I’d not call it the sharpest shift even then.

I’ve had other mid engine and remote linkage cars too - older like a Matra Murena.

I’d not call them brilliant compared to the Mk9 box on my Caterham (Lotus 7) where shifter comes out the back of the box.

What bothers me about all the after market solutions is the long term impact on the synchros and forks. I often wonder if that play helps cut out shifter vibration into the box (even though it’s cable shift) and allows for some give in the shift rather than forcing it down a precise path with knock on to adversely impact the massively fine tolerances in the box itself.

I can say that’s a theory made up in my head so people who understand things like backlash far more than I are invited to shoot me down. However for present having the gearbox oil changed next weekend at the same time as the clutch (apparently they are very sensitive to the right oil) and seeing if there is a new OEM shift bearing are top of my list.

[Marc_986]

Good to see I'm not the only one thinking it needs a bit of improvement.

Originally Posted by Porboxs

What bothers me about all the after market solutions is the long term impact on the synchros and forks. I often wonder if that play helps cut out shifter vibration into the box (even though it’s cable shift) and allows for some give in the shift rather than forcing it down a precise path with knock on to adversely impact the massively fine tolerances in the box itself.

I'm not really worried about that as the cable ends are still rubber and allow a bit of 'give'. The G87/21 box I have is actually a Porsche version of the Audi 0A2 (which I also have, to go behind the audi V8 at a later stage). The audi linkage is much more solid, more comparable to the way BMW operates the gearboxes. If that is good enough in comfort and durability in an Audi, it should be good enough in a Porsche.

When I bought the car, the shift was extremely imprecise, it felt like shifting a lorry, aided by the ultra-stiff worn-to-bits clutch. It had more side to side play than the gates are apart. Main two culprits were the 986 shifter which was simply worn, side to side linkage as well as the bushings. The box itself was also very loose.

I like the idea of the feeler gauge / shim on the 987 shifter. Mind you, his first step was to move away from the 986 shifter if I'm not mistaken.

My rod for the linkage on the gearbox is done. I'll look at the fore-aft as well before I put it in. Fresh fluid is going in as I don't know the history of this box. It also needs a new reverse sensor as the connector suffered a hit. Will steal it from the 0A2 for now.

Also a fun detail on the G87/21 or 0A2 box is that it actually has two detends. One holding the shift fork in position, the other holding the selector rod. This way the fork has a little play when engaged (not when in neutral position) to isolate the wobble of the fork from the shifter.