Author Topic: Strange noise - any ideas  (Read 488 times)

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Offline folkswagon

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Strange noise - any ideas
« on: 22 October 2019, 00:29 »
So, after 12 years off the road my 1968 SemiAuto is running again, but Iím still trying to understand where this noise is coming from. Any help greatly appreciated -

https://youtu.be/winneQGvym0
1968 VW Automatic 1500

Offline volkenstein

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Re: Strange noise - any ideas
« Reply #1 on: 25 October 2019, 08:48 »
Folkswagon,
                  Sounds like bearing rumble to me. Process of elimination now....

1. I hope the GB has correct level of oil in it? lol...and there is oil in there anyway?
 1a. You could drain it and check for shavings/material in your GB oil/drain plate.
 1b. While you are there you can check that big lock ring on the mainshaft nose for looseness.
2. It only happens when a gear is actually engaged but not in Neutral of when the solenoid activates?
  2a. That tells me it is not clutch or mainshaft related.
3. After checking 1., drop the car off those stands. Do the same shifting. I think your CV's are OK because your wheels are spinning anyway.
4. That leaves the layshaft being engaged (ie a gear) with the mainshaft is where your noises start.
5. That'll be ugly as it means you will have to check those bearings. You can drop the engine/GB out after oil draining, then get the nosecone off...you can visually check the rearmost
    mainshaft & layshaft bearings + shim & circlips (and wobble test etc).
 5a. Any else requires fairly major disassembly.

Most bearings are available - except for the mainshaft bearing that is closest to the pinion. Looking around may get you one....but you may be visiting
places where you can pick up a S/H trans.


HTH
Volkenstein
'71 RHD A-S Super - "Klaus"

Offline folkswagon

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Re: Strange noise - any ideas
« Reply #2 on: 27 October 2019, 08:26 »
Thanks Volkenstein :)

So Iíve covered a few of your suggestions -

1a - Iíve drained the oil but as itís a 68 semi auto itís got a drain plug so I didnít take the plate off. Oil looked clear with no shavings. Video was made after new hypoid oil was inserted so thereís definitely enough oil in the GB. Iíve purchased some molyslip gearbox oil additive but not tried it yet, think it would need significant driving to bed that in and as the car is off the road thats not possible at the moment.
1b - As I said I didnít take the plate off so couldnít see any of the gears.
2 - Correct
3 - I know the outer CVís are ok as Iíve re-packed them whilst replacing the rear wheel bearings but donít know the state of the inners. Will try another test today and put the brakes on to stop the rear wheels.
4&5 - There is some good news as I have a complete spare transmission from another 68 semi that Iím cleaning up and getting to know. Only issue found with this box so far is a cracked torque converter housing at the main bolt by the vacuum servo, but with this type of bolt this may be a common problem (see separate picture link). Can the housings be swapped between GBs? If not can it be welded, not sure if itís mostly aluminium or if thereís any magnesium in it?

Although sheís running again Iím going to have to remove the engine as oil is leaking all over the place (mostly push rod tubes) so I want to be able to give it a good check over and replace all that is needed.

Anyway hereís a pic of the now clean spare box and many thanks again for your support :D

Picture of my spare transaxle
Pictures of cracked torque converter housing
« Last Edit: 27 October 2019, 22:04 by folkswagon »
1968 VW Automatic 1500

Offline volkenstein

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Re: Strange noise - any ideas
« Reply #3 on: 28 October 2019, 00:55 »
folkswagon,
                That crack isn't hideous, and non life-threatening. The bellhousings are interchangable between similar years (just about one or two temp sensors). I would suggest you do the old drum kit trick and drill a small hole where the cracking has stopped for now.
A GB swap is certainly a more practical option than mucking around with the gears - you already have one - so off to the races:).

You can autopsy later...

HTH
Volkenstein
'71 RHD A-S Super - "Klaus"

 

anything