Please help diagnose shifting problems

[Xcellr8]

Boxster with 5 speed manual that is new to me, with no available history. Meaning I have no idea when clutch was last replaced.With car on jack stands, and motor off, the tranny will shift into all gears.With car on jack stands, and motor running, the tranny will shift into all gears.With car on the ground, and motor off, the tranny will shift into all gears.With car on the ground, and motor running, the tranny will only go into 3 and 4th (never tried 5th). It will not shift into 1st, 2nd, or reverse.On the road, with only 3rd and 4th, there is no grinding with those two gears, and when I try to find 2 in a downshift, there is no grinding, just won't go into gear. So I thought it was a shifting linkage problem, EXCEPT that it goes into all gears with motor off.Since it finds all gears with the motor off, while on the ground, I believe motor and/or transmission mounts are okay.With car on the ground and motor running, when I try to shift into 1st, 2nd, or reverse, there is no grinding. Oddly enough however, when I tried to shift into reverse to back out of the garage, the car would go back a few inches almost like it was in gear (which it wasn't though it may have been close). Strange.With car on the ground and motor off, put tranny into reverse, depressed clutch and tried to start. Car would not start, but it would roll backwards a few inches as the starter motor was slowly turning the engine. So, I thought it was a clutch problem.Tried bleeding the clutch, no difference (but allow that my method was not the approved pressurize the system)Now, I am not sure what I have. A bad clutch (though no grinding), or bad linkage (though it finds all gears with motor off), or do the mounts change with the motor running (meaning I discounted that item prematurely?)Obviously, I am confused. Can you help?Thanks,Joe

[Ahsai]

Sounds like your clutch is not completely disengaging even when the clutch pedal is fully depressed. Can you confrim also with car on jack stands, and motor running, the tranny will shift into all gears but the wheels will be spinning even with the clutch fully depressed?

I would pressure bleed the clutch properly first.

[Xcellr8]

Thanks for the reply, you are the first from three different forums. I really appreciate it.

Yes, the wheels do spin even with the clutch fully depressed. Agree that clutch is not fully disengaging. Bleeding is cheaper than replacement, but just for discussion...How would a faulty slave cylinder appear different from my experiences? And, besides the hydralics of the slave cylinder, is there any mechanical part (I'm thinking spring - as in clutch release lever) that could be the issue, and if so, how would I test to pinpoint which problem I have?

[Ahsai]

You're welcome. Yes, a faulty slave cylinder will cause the exact symptoms and so do other mechanical parts inside like you said. Just start with the simplest, which is bleeding the slave properly to make sure there's no air in it. If that doesn't work, either you throw in a new slave cylinder (and hope that's it) or you remove the transmission to do a full inspection - also a good opportunity to address the IMS/RMS the same time too.

Please refer to the DIY tutorial here for 996. It should be similar http://www.renntech.org/forums/tutorials/article/54-brakeclutch-fluid-change-and-bleeding-instructions/ Make sure you start with the brake fluid at MAX before bleeding and with plenty of brake fluid in the bleeder. The clutch fluid has a seperate (and small) partition inside the reservoir seperated from the brake side and it's easy to "bottom out" if fulid supply is interrupted from the bleeder. If not at MAX, you may inadvertantly introduce air in the clutch side when you bleed. I always use a pressure bleeder (per the DIY) and do not know other reliable ways.