Erratic behaviour of the gearbox

thob

thob

Member
Since some time I observe (aka I'm having troubles) a very strange behaviour of the P6 3500S gearbox.
1) the reverse gear hardly stays in place if there's onyl a tiny object in th way or it's uphill. And shifting makes a lot of noise 90% of the time
2) I cannot shift any gear (I tried mainly 1 st| reverse) if the engine is cold and running
3) I can shift any gear if the engine is not running
4) When I start the engine with 1st gear in place and drive I generally have no issue with shifting gears (except reverse gear see 1) if the engine is warm.

any ideas where this is pointing to? I fear at some point I can't shift anymore at all.
 
If reverse jumps out then it can be the carpet on the tunnel stopping the lever going fully backwards, or the gearlever seat and/or acorn worn, the selector striker lever worn, the reverse light switch stopping the selector rod goung fully home, or the selector fork incorrectly set on the selector rod inside the box, to mention a few. All the rest sound like clutch issues, so set all that up properly and check the gearbox oil level as a first step.
 
Here's how to set up the clutch:

Pull back the carpet and underlay and set the brake pedal height between the bottom of the pedal and the floor to 6 & 7/8"
Set the clutch pedal level with the brake. This is done on the threaded rod into the master cylinder (under the bonnet on the 3500S).
Push the clutch operating arm rearward until the release bearing touches the pressure plate and make sure the arm is one spline forward from vertical. Remove the arm and move it on the splines if it's not, and take care not to drop the nut in the bellhousing.
Pull back the slave cylinder boot. Adjust the pushrod so that the piston is about 1" away from the circlip. (Pedal at rest)
Wind the stop bolt all the way in. (Thats the one in the footwell.)
Then get someone to slowly depress the pedal as you look at the piston in the slave. What you need to get is the piston just touching the circlip when the pedal is on the stop, and you achieve this by adjusting the pushrod each time just before the pedal is depressed.
Once you get to the point that putting your foot on the clutch down to the stop makes the piston touch the circlip in the slave, lock the nut on the pushrod.
Then wind the stop bolt up one turn, and lock it with the nut.
Depress the pedal again and make sure there is at least 25thou clearance between the piston and the circlip in the slave.
If not wind the stop bolt up some more a turn at a time.
Refit the carpet and IIRC that's it.
 
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