bearing noise from trans ?

[jedidan]

Finally got my 68 AS bug running today with much delight.(the previous owner had it sitting quite some time). I know the engine will need work, so i will plan a rebuild on my next holiday. I noticed a 'rumbling' sound coming from the transmission. (can hear more from within the cabin than from the outside). The rumbling disappears momentarily when I shift into the gears, but it is there all the time. Is this some sort of main bearing or throw-out bearing noise ? Most importantly, is this a relatively easy fix ?

[bookwus]

Hiya Jed,

A little more information would help.  Is the car actually underway (on the ground and running) when you hear this noise, or do you have it up on jackstands?

If the noise is present ALL the time, except when the tranny is shifted it is not likely to be the throwout bearing.  If this occurs while running on the ground it may be that your CV joints need attention.

However, since this seems to occur all the time (if I'm reading you correctly and that would mean - to me - that the noise is present in all ranges including nuetral) I would guess that the source is NOT inside the tranny case, but in the bellhousing.  TC, flexplate, pressure plate would be my initial guess.

[jedidan]

Hi Bookwus,

Thanks for the various indications - my apologies, I should have been a little more succinct - the car is on its four wheels in my backyard, I'm only moving back and forth, not cruising speeds - therefore the Cvs are not getting any serious action. The noise is present in all gears, including neutral. The car has done 126,000 miles and has had an engine swap to a 1600 TP at approx 115,000 miles. Up until now i had only experienced manual gearbox VWs, the AT is a new concept to me. From your speculation, my guess is that the transmission can remain in the car for the repair, which is good news for me since I've got only one pair of hands working on this car. Are parts in the bellhousing area easily obtainable ?

[bookwus]

Hiya Jed,

Unfortunately clutch components (disc, pressure plate and throwout bearing) are among the hardest-to-find parts for an AutoStick.  I think it IS still possible to locate these parts (given time, persistence, cash and luck) but I'm just as sure that there are others who will disagree.  You need to talk this over with a fellow countryman like Sean or Lee to see what might be available down in Oz.

As far as the tranny remaining in the car.................do know this...........a diagnosis via e-mail is not worth very much.  Just a guess when you get right down to it.  On the other hand, the AS transmission is a very robust unit which very seldom requires internal repairs.  Most AS related problems are found in the supporting systems (electrical and vacuum) outside the actual transmission case.

That the noise occurs is ALL ranges including nuetral tells me that the internals of the transmission are likely NOT at fault.

Best of luck to you Jed.  Keep us posted on what you find.

[68AutoBug]

Hi Jed,
My gearbox is the same....
Its been sitting since 1998 with New Hypoid gear oil in it..
which VW recommends using... well must be used....
and Now I've just found out this year, that the Bentley VW of America workshop manual states that" You shouldn't store the car with the Hypoid oil in the transmission, as it eats the zinc used in some of the bushes in the Gearbox..."  another oil should be used in storage..
I've had Ny car on the road since DEC last year, but I've only done 1500kms...as its very noisy inside the car, but OK on the outside...
I also have a very noisy exhaust system...
I have since found a replacement gearbox, which i have to install in the future...   the noise is always there... even in neutral...
My Noise was very noisy at first, but after a few kms it quickly dropped down... and the really bad noise has gone... I can hear the Radio driving around town where I couldn't hear the Radio at first...
I have put about 300mls of Molydebnium additive into the gearbox..
this may stop any further wear.... but I usually don't go past 30kms from home.... just in case.... lol...
So, the problem won't go away I'm afraid jed...
You could try some Molydebnium [My spelling] in Your gearbox, and if its not too badly damaged the bushes.. You may be OK...

Best of Luck

Lee -- 68AutoBug -- Australia --

http://community.webshots.com/user/vw68autobug