Tranmission grinds going into reverse when my car is first cranked

[Greek55]

Lately, since weather has cooled, my car will not go into reverse after first cranking in the morning. It is as if I am not pushing in the clutch. I cut the car off, put it in reverse and then crank and everything is fine. Next time I put in reverse there is no problem until the next morning. My car is garage kept and it hasnt been below 40 degrees outside at night yet.
I have Swepco in it and the car has about 110,000 miles on it. I have not checked the level of the Swepco since I put it in a year ago. Any ideas on what might be the problem?

[jtfreels]

Mine acts the same way, my solution, that works most of the time is slip into first then go back into reverse. About 98% of the time no grinding (a made up percentage, but most of the time). Think I read this method somewhere here.

Jay

[Wayne 962]

This is a common problem, and it means that your clutch is not well adjusted. It's also grinding into 1st, 2nd, 3rd, 4th, and 5th, but the synchros are wearing instead of "grinding". Very big problem, and if you continue in this situation, you will need a transmission rebuild (to replace worn synchros) very shortly. In fact, this "reverse test" is what I tell people to use to test their clutch adjustment in the "101 Projects Book".

If you put the clutch in, the transmission will spin down, and it *will not* grind, if your clutch is adjusted properly. If it grinds even a little, then you have a serious problem on your hand, one that is masked by the synchros in the forward gears. The solution is simple - adjust your clutch so that it's full disengaged when the pedal is in. This also could be a sign of the clutch wearing and failing.

-Wayne

[Wayne 962]

Originally Posted by jtfreels

Mine acts the same way, my solution, that works most of the time is slip into first then go back into reverse. About 98% of the time no grinding (a made up percentage, but most of the time). Think I read this method somewhere here.

Jay

This technique should be used to go into 1st from a stop, but not with reverse. When putting the car in reverse, you have to put the clutch pedal to the floor, and then wait about 5-10 seconds for the transmission to spin down. Then put the car in reverse. It should not grind. If the car doesn't want to go into reverse (happens about 10-20% of the time), then let the clutch pedal up and spin the internal shafts in the transmission for a second or so. Then put the pedal in again and wait 5-10 seconds, and then put it into reverse.

If you wait 5-10 seconds, under no circumstances should the transmission grind going into reverse. Leaving the car in this situation will result in me selling you some syncrho rings and sliders in the near future...

-Wayne

[Eagledriver]

What Wayne describes is exactly right for making sure your clutch is adjusted correctly. Once you have done that though you can select 3rd momentarily before selecting reverse. You are using the third gear syncro to stop the spinning of the gears so reverse can be selected without waiting 5 to 10 seconds.

-Andy

[gigem75]

110,000 on clutch??? if so might be time for a clutch, might be adjusted as good as it's going to get, but yes, check the adjustment first.

[Greek55]

Clutch was replaced at 75,000 miles. I will use my 101 Projects book and try to adjust the clutch.
Thanks for your help.

[Greek55]

One more question, please.
It only does this when the car has not run about 12 hours and is cold. After engine/transmission warms it goes into reverse with no problem, smooth as ever.
Do you still think it is a clutch adjustment problem?

[Mike Andrew]

Clutch adjustment is well detailed in 101 & Bentley manual. Not at all a difficult task to perform and not very time consuming. Well worth the effort.

[RWebb]

Originally Posted by Greek55

One more question, please.
It only does this when the car has not run about 12 hours and is cold. After engine/transmission warms it goes into reverse with no problem, smooth as ever.
Do you still think it is a clutch adjustment problem?

may be just a tad out -- this the easiest & cheapest thing to do ---> so do it 1st

[wesayso]

Originally Posted by Greek55

One more question, please.
It only does this when the car has not run about 12 hours and is cold. After engine/transmission warms it goes into reverse with no problem, smooth as ever.
Do you still think it is a clutch adjustment problem?

This is exactly the behaviour I am currently experiencing. After I have driven a couple of miles (kilometers in my case ) I can change to reverse without grinding so I adjusted the clutch only to find it still behaves the same.
I'm thinking the bearing between the main transmission axle and the crank is sticking.

Starting the engine while pressing in the clutch at startup helped. No more problems choosing reverse.

Did you have any success adjusting the clutch to resolve this problem? A new clutch will obviously help as long as the bearing is replaced too. But my clutch doesn't seem to be totally gone just yet. Gear changes have improved from the clutch adjust though.

[Greek55]

I am going to adjust my clutch this weekend, however I have not had the problem since I initially posted this thread. Our weather has been 60 degrees plus for a week. It only seems to be a problem when the outside temperature is cold.

[eR1c]

Originally Posted by jtfreels:
Mine acts the same way, my solution, that works most of the time is slip into first then go back into reverse....

Jay,
This technique should be used to go into 1st from a stop, but not with reverse.

Jtfreels says he puts his car in 1st to get into reverse..wayne says this technique should be used to get into 1st but not reverse. ....seems these two statements don't make sense? I didn't know there was a trick/technique for getting into 1st from a stop. I'd like to know it though -as I have this problem on occasion.

[jtfreels]

I just got back to this thread, Wayne mentions, put in the clutch and wait 10-15 seconds, when I had a slight grind into reverse today, I know I didn't wait that long.

I'm guessing my put in to 1st is just me doing the waiting bit with out really waiting.

Jay

[Formerly Steve Wilkinson]

What Wayne means, I believe, is that it's accepted technique to shift into first at a standstill with no grinding by first putting the transmission into second, then first.

[eR1c]

Thanks Steve ...put into 2nd then 1st! -will try it!

e

[Greek55]

I adjusted my clutch and still, only when cold, reverse will sometimes grind. It is as if I am not using the clutch. Not the slow kind of grind you would get is it was idleing too fast. If it grinds I can shut the car off, put the shifter in reverse, start the car and put it in neutal then back in reverse with no grinding. It is as if something is hung up in the transmission when cold and gets unhung after the car is put into reverse.
Any ideas?

[Otto]

It is not the clutch at all, it is the viscosity of the oil. When the temperature is cold, the trans oil is about 150 weight. If you know anything about transmissions, you will know that third gear is the preferred gear to engage before engaging in any other gear.

[David E. Clark]

Here is a similar answer to Otto's from the Porsche Club of America tech section.

[Grady Clay]

Both John (Outomatic) and Wayne (Bird Store) have already posted a large part of the overall picture.

Another is also a worn or greasy clutch disk.

Worn first:
The disc, pressure plate friction surface and flywheel friction surface all 'wear-in' over their (limited) life. This causes them to become ‘too friendly’ where there is ‘stiction’ between the friction surfaces. Anyone who simply replaces a clutch disc (and not the other worn parts) can see this.


Oil on the disc:
This is a common and insidious problem.
Wayne brings this up.
Any transmission oil that (usually) leaks past the transmission input shaft seal, contaminates the clutch disc with oil. In turn this causes the clutch friction disc to stick to either the flywheel or the moving part of the pressure plate. Since these parts are huge (215-225 mm) compared to the transmission syncros (largest xxx mm) the ‘dragging’ big clutch overwhelms the puny syncro.



In any case, the transmission syncro is stressed (in case of the non-syncro reverse and overwhelmed 1-5 syncros) causes ‘clashes’ of the engagement dogs or gears.


Later Porsches have reverse syncros to mask (my word) this issue.

Best,
Grady