Author Topic: Shifting problems  (Read 6919 times)

Tez

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Shifting problems
« on: December 03, 2006, 07:07:24 AM »
Hi everyone
can someone help? my problem is that at times the car is fine and the clutch engages when i first start up the car but after a short period of driving the clutch no longer seems to engage so i have to shift using just the revs (which i guess is not good :cry: ) the gears seem to stick in gear and i have to force the gears to get it to engage, if anyone has any ideas please let me know!! any help would be appreciated

bookwus

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Shifting problems
« Reply #1 on: December 03, 2006, 08:44:44 AM »
Hiya Tez,

So.........basically what you're saying here is that sometimes it will shift and sometimes it won't?  Is that correct?

It's important to know just what happens when you try to shift and find that you cannot.  Do you get grinding?  Does the shift lever move or not move?  Any noise or movement (or lack of either) that you note will help in determining a possible cause.
ike

70 AS Bug

Tez

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Shifting problems
« Reply #2 on: December 03, 2006, 11:29:22 AM »
Hi Mike
Thanks for your reply, since posting i have driven my bug and it seems as though the clutch si not engaging at all now :cry: , i can move the gearstick and with the engine off is free to move, with the engine running it will move into gear but will sometimes grind going in and will 'lock' the gearstick in gear until the engine is switched off, hope you can help
Tez

bookwus

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« Reply #3 on: December 03, 2006, 07:18:12 PM »
Hiya Tez,

Thanks for the additional information.

First off, know that this sounds like a VERY fixable problem that will not involve you having to get inside your transmission.  A little time fooling around with the vacuum system and the electrical system should have you back on the road without any problem.

The grinding indicates that the clutch is not doing its job.  The question, of course, is ......Why isn't the clutch doing its job?  Shifting in an AutoStick is an electrical operation with a vacuum assist.  So, your problem will be found either in the electrical system or the vacuum system.  In order to get it fixed you will need a Robert Bentley Service manual appropriate for you car and a handful of common shop tools.

Next thing coming up in this letter is a piece I wrote some time ago concerning troubleshooting and maintenance in an AutoStick.  I'll bold the parts you need to check out.............

Trouble Shooting an Auto-Stick
A Little Background
Prior to the Auto-Stick, Volkswagen had marketed a wholly mechanical semi-automatic transmission in Europe called the Sax-o-matic (also referred to simply as a Saxomat). Encouraged by the response of customers in Europe and with an eye on the increasingly upscale market in the United States, VW began development of an improved semi-automatic transmission in the mid sixties. VW introduced its Automatic Stickshift transmission in 1968. It was available in Standard Sedans, SuperBeetles, and Karmann Ghias throughout its production run (until 1975).
The Nature of the Beast
Basically, the Auto-Stick allows for driving without the necessity of shifting gears, as in a manual transmission. For that matter, many trips may be made without shifting of any kind. However, it is not an automatic transmission in the sense that term is used today. Technically, the Auto-Stick is a dry-clutch, three-speed, semi-automatic transmission which makes use of a torque converter.
The driver, unemcumbered by a clutch pedal, has the option of going through the gears as one would with a manual transmission; Low, First, and then Second. Shifting occurs by simply moving the shifter to the desired position while easing off the gas pedal. Or the driver could simply leave the shifter in First for around town driving. Although the start off the line is slow, the driver even has the option of setting the transmission in Second and leaving it that range as he drives.
The shifting pattern is in a typical three-speed "H" format. Upper left is Reverse, lower left is Low, upper right is First, and lower right is Second. Reverse, as with all VW transmissions of the day has to be depressed to engage.
VW refers to the AS shifter positions as "ranges". Low range is designed for starting off under a load or uphill. First range accommodates most around-town type of driving speeds up to approximately 45 MPH. Second range is the choice for highway driving speeds.

Checking Out the Auto-Stick
Shifting gears in an Auto-Stick is an electrical operation accomplished with the aid of a vacuum assist. There are many individual components to the vacuum assist system, such as the hoses, clutch servo, control valve, and vacuum tank. This being the case, it is almost always a good idea to troubleshoot the vacuum system first when something goes wrong.

The Vacuum System
Leaks anywhere in the vacuum system can result in symptoms such as poor (slow or jerky) shifts. Actually, the vacuum hoses and their clamps should be replaced on a regular basis (like every 10,000 miles). So, look the hoses over carefully for signs of wear or cracking. Also check to see that the hoses are keeping their natural shape; which is to say......not collapsing. Hoses in the vacuum system should be wire-reinforced. Replacement hosing can be obtained at a local hydraulics shop. Also while doing this inspect the clamps and be sure they are tight.
This is also a good time to thoroughly examine your vacuum tank (under the driver's side rear fender) for leaks. It is prone to gravel spray
from the rear tire. Lastly, in doing a "vacuum check" take a good look at the control valve and the clutch servo. The control valve is not likely to be leaking (although that is a possibility) but may need to be adjusted. See any good manual (Haynes or Bentley. Having at least one of these manuals is an absolute necessity.) for this procedure.
Be sure that the vacuum hose from the control valve to the carburetor is hooked up to the proper vacuum nipple on the carburetor. That nipple (and its source) should be above the butterfly for proper shifting action. This would be an excellent opportunity to remove the control valve air filter and clean it out. Another chore to do while you're back in this area is checking the Automatic Transmission Fluid level in the ATF reservoir. The ATF dipstick is built into the reservoir lid which can be found on the right hand side of the engine compartment. The fluid should be checked while warm, but the engine should not be running.
The Clutch Servo
The clutch servo may well be where you are experiencing any possible leaks. Check it carefully to see that it holds a vacuum. To check the servo for leaks, remove the vacuum hose from the control valve where it attaches (the vacuum opening) to the servo. Move the clutch arm toward the rear of the car so that the servo's internal bladder is pulled out of its resting position and fills the servo with air through the vacuum opening. Place your thumb over the vacuum opening and observe the bladder action through the holes on the side of the servo. If the bladder deflates, you have a leak. Replacing a clutch servo is rather common in an Auto-Stick with more than a few miles on it. Rebuild kits are readily available and of reasonable cost. The only real hassle involved with the clutch servo is its location, which is just above the left heat exchanger. To remove or adjust the servo, youšll likely have to remove that heat exchanger first.
If the servo bladder holds a vacuum in the test above, your servo is airtight, but may need to be adjusted. Actually, what is really adjusted is the clutch free play. This can be accomplished by following the directions (you'll have to make a gauge too - the directions for that are in the manuals also) in either Bentley or Haynes. Should you find that you cannot adjust the clutch free play "out" any more, you will have to remove the engine and replace the clutch. However, do know two important facts about the clutch before you go tearing into it. The clutch disc and pressure plate have a remarkably long lifespan in an AutoStick. I have pulled apart OEM clutch assemblies in cars with way more than 100,000 miles and thirty years and the components were still in very good working order. Can the clutch wear out or go bad? Certainly! But the odds against it are on your side. The other thing you should know about the clutch assembly is a bit more somber. The parts inside the bellhousing are extremely difficult to find. Impossible is more like it in certain cases. Bear that in mind as you get into the clutch assembly.
The Electrical End
So, let's say your vacuum checks out. Next, try the electrical end of all this. Your shifter has a set of points within it. Normally the action of moving the shifter will cause the contacts to touch and complete the circuit to the control valve. When these points make contact the Auto-Stick can do its job and the driver is able shift the transmission. Poor contact or no contact is going to result in gear gnashing and other assorted transmission horrors. So you'll need to check out the condition and the gap of your shifter points. Again, a good manual can instruct you in this procedure.
While you're down there adjusting the points, trace that blue wire coming out of the bottom of the shifter. It should lead back under the rear seat to a connector. Because this connection leads back to the control valve, it must have a solid contact at this point, so check that out. But you're not finished here. Back in the engine compartment (usually in the upper left hand corner near the coil) you'll find two in-line fuse holders. One of those fuse holders governs the back-up lights. The other one, which will have a lead connecting to the solenoid on the control valve, transmits power to the control valve. Check to be sure that this fuse is in good shape and its contacts are clean.
It would also be a good idea to get a continuity checker and check out the electrical switches (the neutral safety switch and the ATF temperature switch) on the transmission itself (they're over on the passenger side of the tranny behind the right heater box head).
Something Else
If everything mentioned so far checks out well for you, remember this; the better shape your engine is in (all things being equal) the better your Auto-Stick will perform. Due to its vacuum connections, the Auto-Stick is more sensitive to a well tuned engine than a manual.
Take a good hard look at your carburetor, especially around the area of your vacuum lead to the control valve. Look for any gas leaks; anything which might indicate a loss of vacuum at that point. Check your carburetor adjustment. Regap the points and plugs. Retime your engine. In short, make sure your engine is tuned up.

Do Know This
Although it adheres to the basic Volkswagen philosophy of good, sound transportation, the Auto-Stick transmission has been frowned upon by a number present-day VW fans. Changing Auto-Sticks over to manuals has spawned websites aimed at helping to accomplish this task. Yet the Auto-Stick itself is a reliable and functional transmission. Many of the parts, such as the case and gearing are actually built to the same high tolerances as the manual. If well maintained, the Auto-Stick will deliver many years of dependable and useful service. Most of the problems encountered by Auto-Stick owners can be handled by observing the procedures listed above in this article."


Take a crack at those boldened areas and check back with us and let us know how its going.
ike

70 AS Bug

Tez

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Shifting problems
« Reply #4 on: December 04, 2006, 12:19:07 AM »
Mike
Once again many thanks for your reply, i'll check out the various vacuum pipes and electrical system and report back what i find, the comprehensive piece you've just written is great and thanks for your help!

Tez :D

68AutoBug

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« Reply #5 on: December 06, 2006, 06:25:18 AM »

Hi Tez and Mike,
Odd problem that one...
Normally, You would look at the control valve when the engine is going, to see whether its activating when you touch the gear lever...
This will be very difficult when you are driving the car...  lol..  :)
So, it could be electrical or a Vacuum leak as Mike suggested..
With the engine off, [Ignition On] You can change gears about 5-6 times maybe more, using the vacuum in the vaccum tank..
so try doing that about 5 minutes apart...
If that is successful, Your Vacuum tank isn't leaking...

Then try it with the engine going, and if You can't change gears, it sounds electrical to Me...   and maybe the control valve isn't working all the time.
Loose wire on the control valve or where ever the power is taken from....
[coil?]  also the electrical connnection between the gear lever and the control valve maybe faulty... check all connections...

Best of luck

Lee Noonan  - 68autobug - Australia -

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Tez

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Shifting problems
« Reply #6 on: December 11, 2006, 12:49:40 PM »
Hi Lee and Mike
PLEASE help!! I've taken her to the garage i normally use and we had a look at the car, it seems the solenoid is kicking in as you would expect and with the engine running the clutch appears to be working ie. the clutch arm is moving as it should.  problem being is that it grinds when going into gear and then sticks in gear, this now happens when the engine is NOT running!!! :(  so does this mean the gearbox needs overhauling?? because if so i'm looking at a huge bill. Are clutch plates available? and also do you know if bits are available to overhaul the gearbox and if so who from??? please help a poor person so close to christmas!!!! :(

68AutoBug

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Shifting problems
« Reply #7 on: December 11, 2006, 03:35:54 PM »
Hi Tez,
Normally, to stop the car from crunching into gear, the clutch Servo
adjuster is adjusted.. You need to undo the locking nut... and turn the adjuster one turn towards the adjusting nut... this should shorten the adjuster... so the arm will move the clutch thrust bearing more...
and this would normally stop the crunching...
I have heard that a normal 180mm clutch plate can be modified to use, also You can get the original clutch plate relined...
The clutch plates wear very little as they are either in or out... there is no slippage, which wears the clutch plate out...
If You have clutch pressure plate problems....
It may need to be replaced... and I'm not sure where you would find one of those...   The rear of the gearbox has to be removed to access the clutch and to access the bolts, the bottom plate must be removed..
Try the adjustment above...
that is the normal thing to do....
cheers

Lee Noonan

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bookwus

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Shifting problems
« Reply #8 on: December 11, 2006, 03:47:43 PM »
Hiya Tez,

If everything is working as it should; solenoid activates the control valve, clutch servo moves the clutch arm, then there is one last item to check before you haul out the wrenches.  Everything can be working just fine on the outside, but your clutch may be out of adjust.  

Look carefully at your clutch servo rod (the servo moves it and the rod is connected, in turn to the clutch arm).  On that servo rod you should see a long adjusting nut/sleeve and a keeper nut.  Gently back off the keeper nut.  Then turn the long adjusting nut/sleeve 5.5 turns AWAY from the keeper nut.  Then tighten the keeper nut up against the adjusting nut/sleeve.

Now check to see if that makes any difference in the shifting action.  If it does, you know that your clutch is simply out of adjust.  If it does not, then, at the very least, you'll be looking at getting inside the bellhousing to examine the clutch components.

Keep us advised and good luck!
ike

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Tez

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Shifting problems
« Reply #9 on: December 11, 2006, 04:08:51 PM »
what worrys me is that the gearstick gets stuck in gear even when the car is not running? what could cause this? thanks for the replies guys!

68AutoBug

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« Reply #10 on: December 11, 2006, 10:05:20 PM »
Hi Tez and mike,

I don't know about that one...
the selectors can be bent...
this is fairly common in normal gearboxes...
but haven't heard of it before in semi autos...
Have you had the gearlever OFF ??
the plate may be in the wrong position, or the small bush below the gearlever may be worn out...
these are failing in standard gearshifts.... but again, haven't heard of anyone with an auto having any trouble with the bush...
the bush is very inexpensive, but a pain to replace..
its in the tunnel slightly rearwards to the gearlever...
this would allow the gearlever to drop down slightly...
but what effect it has on the gears I don't know....
it must have some effect, otherwise they wouldn't get replaced....

I think Mike, if the clutch servo was 5.5 turns out of alignment, He wouldn't be able to select any gears with the engine running...
I adjusted Mine so I can select the gears without grinding, unless I really push it into reverse quickly... I just feel My way into reverse...
99% of the time it doesn't crunch.... and it doesn't crunch when my wife drives either.... better than having it too far adjusted and the throw out bearing spinning all the time....

cheers  Best of Luck Tez..

Lee

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bookwus

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« Reply #11 on: December 11, 2006, 10:42:18 PM »
Hiya Lee,

I just gave Tez the write-up in the Bentley on adjusting the clutch.  I paraphrased it, but the details are just what Bentley specifies.
ike

70 AS Bug

68AutoBug

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« Reply #12 on: December 12, 2006, 12:33:59 AM »
Hi Mike,
doesn't the Bentley only tell how to adjust for a NEW clutch plate?
All the other manuals do too...
I haven't read how to adjust the clutch 30 years on...
although I would just adjust the servo adjuster right back and keep adjusting until the clutch works OK....
I haven't heard of anyone having pressure plate problems...
but I suppose there may be some very high mileage units out there..
I know some people have had their gearboxes overhauled...
but why, I don't know...
Anyway. I hope a simple adjustment will fix his problem...
otherwise its a gearbox job....

cheers

Lee Noonan..

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Tez

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Shifting problems
« Reply #13 on: December 12, 2006, 02:08:10 AM »
if it is the gearbox where could i get a recon one from? because in buying a second hand one you don't really know what your getting??

volkenstein

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« Reply #14 on: December 12, 2006, 02:42:35 AM »
Tez,
     Steve (Crasher) rebuilt his (he's in the UK), but he chased high and low and all over the world for bits 'n' pieces. I suggest you PM him.

I'd try everything that has been suggested first before contemplating pulling the engine & gearbox, as any trans nasties will be right inside it and will require the gear housing to come off to check.

An oil drain may reveal a little but won't tell the whole story.

It's always a punt with second hand GB's.


Volkenstein
1 Super RHD Semi-Auto "Klaus"