Calling all Sportomatic experts

[AUS911SC3]

Believe it or not but I actually love driving my Sporto. It's a 78 3.0lt euro spec and runs strong but the most annoying thing is it struggles to hold third gear unless I actually hold it in gear when driving. Even if I accelerate or hit a bump in the road it will fall out of 3rd, really annoying. Incidentally 1st and 2nd gears are perfect.
So everyone, anyone any ideas ? Really appreciate your help..

[boxster03]

The microswitch on the shift linkage likely needs attention/adjustment - they are always suspect in disengaging the clutch and were a weak link in the system. many drivers found they rested their hand on the stick like they did with a manual box and just that slight pressure would activate the microswitch and disengage the clutch. I suppose heavy jarring can do the same

[Scott Douglas]

I suggest you start by looking at your shift linkage bushings.
Laying your hand on the shifter is a big no-no with a sporto and should cause the clutch to disengage as boxster03 noted. If the bushings are worn then the movement of the shifter when going over bumps etc will cause it to move enough to activate the switches.

[RussR]

I think jumping out of gear is a bit different to engaging the microswitch

my microswitch is in near perfect condition but on big bumps sometimes the clutch engages, it doesn't jump out of gear though

i'd be checking out the linkage bushes, I assume it'd be the same procedure as the 915 box to change them