Sometimes Grind when going into gear sitting still w/ clutch in?

twilightcall · 04-01-2006, 04:26 PM

Sometimes after I start my car (ex. after filling up with gas) I will push the clutch in and go to put it in gear and sometimes it will grind. I will then release it and push it in again and it is ok. It happens every now and again. What causes it to sometimes do this? I have been starting it in gear and pushing the clutch in to keep from doing this as I don't want to harm the transmission. The clutch catches about half way between the brake pedal and the floor. Thanks.
82 911 SC

lateapex911 · 04-01-2006, 04:29 PM

Is there a pause after you push the clutch until you select the gear? Sometimes waiting will let the input gear stop spinning.

twilightcall · 04-01-2006, 04:31 PM

Yes, sometimes I even push the clutch in once and then out and then in again. I will wait about 5-10 secs.

lateapex911 · 04-01-2006, 04:36 PM

When the clutch is engaged, (up) the input shaft is spinning the gears at engine speed. (Gurus correct me here, LOL)

When you disengage the clutch, the gears stop spinning. In older cars with looser bearings and such, it can take a bit longer.

If thats the case, it's a livable thing.

Two ways to avoid it.
1- Depress clutch before starting engine
2- depress clutch and wait a bit if engine is running

If that doesn't do the trick, there could be drag that is causing the input shaft to turn when the clutch is depressed, such as bad a throwout bearing.

BrokeMyCar · 04-01-2006, 04:51 PM

As I understand it, good synchros are meant to reduce the likelihood of this problem. My 82SC does exactly the same thing; I've always attributed it to worn synchros and the endearingly goofy 915 transmission.

Does anyone here double-clutch on a transmission with worn synchros? I've never tried...

Babak

twilightcall · 04-01-2006, 04:54 PM

Thanks guys. I always started it with the clutch in. Maybe for some reason I forgot today. I always try to though. I will sit there longer with the clutch in and see if it helps. Thanks Again.

Oh Haha · 04-01-2006, 06:19 PM

When was the last time the clutch cable was adjusted?
I would check into that as well. It's very easy to do.

twilightcall · 04-02-2006, 04:53 AM

I honestly have no idea. I think I saw the adjustment when I was changing the gear oil. I might try that. Any tips on adjusting? On this car are you taking the slack out of the pedal or is it a constant contact throw out bearing so when you adjust it the pedal comes down with the adjustment? Thanks.

Dueller · 04-02-2006, 05:09 AM

See item 3 on adjusting clutch cable:

http://www.pelicanparts.com/techarticles/911_shifting_improvements/911_shifting_improvements.htm

Motorhead-45 · 07:56 AM

I believe the grind happens because your transmission input shaft is still turning when normally it should be at rest with the clutch peddle depressed if I'm not mistaken. Someone will correct me I'm sure if this isn't correct.

First adjust your cable. There is an article in the tech section of this board on the procedure.

http://www.pelicanparts.com/techarticles/911_clutch_cable/911_clutch_cable.htm

This procedure is also covered in Wayne's "101 Projects or your Porsche 911 book" ....another good resource to have.

If that doesn't cure the problem then you need to look deeper at the clutch and throwout bearing assembly as the possible culprit.

87924gt · 87924gt's Garage

KISS Kepp it simple... I often find that looking at the easiest fix 1st is the way to diagnose what the cure will be. I too say look at the clutch cable (adj) and also the helper spring and its' workings.
Steve E

midlife · 04-02-2006, 09:08 AM

Just for clarification, the throwout bearing cannot cause this. The throwout bearing only contacts the pressure plate which is spinning with the flywheel.
The pilot bearing in the flywheel can cause this, as it contacts the input shaft.

michigan · 04-02-2006, 10:04 AM

If your syncros are still turning and, your idle is high, you will often get a grind. The thing to do is slide the transmission into fourth gear and then slide it into 1st. The syncro gear should get in line with this manuver. Try it.

bigchillcar · bigchillcar's Garage

common in 1st gear on these cars when the trannys haven't seen rebuilds in their lifetime. often the cable is just slightly out of adjustment. a technique that many use is to push in the clutch and 'touch second'...this means pull it down just slighty into second (thus the touching it reference), this stops the spinning..then push up into first. this is 'standard procedure' on my car, otherwise i have to push in the clutch and count to 3 before shifting into 1st. i find 'touching second' works faster than the counting method.
ryan