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Tue Jun 01, 2010 10:09 am

At 40mph +/- 5mph I'm feeling an oscillating vibration (hard to pinpoint but most noticeably from the accelerator pedal) I'm also hearing a very low level hum. Cycling about 1.5 / second. Either side of 35-45 I do not feel/hear this oscillating vibration/hum.

I initially thought it was a misbalanced wheel, I had new tires put on and immediately noticed the vibration. It does not happen in neutral at 40, nor do I sense anything in 3rd at 40 (although the engine is then making enough background noise so as to be louder than what I hear when in 4th)

I do not know when the tranny oil was changed, I've put 5K on the van since buying and a visual check (dipping finger in oil filler) shows it to be very clean/clear.

Does this sound familiar to anyone, any pointers? a search threw up nothing.

Thanks all! /pauric

Tue Jun 01, 2010 11:27 am

how is your clutch??

Tue Jun 01, 2010 12:18 pm

Seems tight, definitely not slipping. Had a long drive yesterday with four people +gear, she pulled us up over the Lincoln gap which has a max gradient of 24 in places http://www.brentacol.com/h/lincoln_end in 2nd no problem, and 5 hours later near home I was tired and closed the clutch a little too sharply a couple of times and noticed the engine snap back at me (o;

So, I think it's good.

I think I'll take it back to the shop that mounted the wheels and ask to recheck them. The only glitch is I had it done last year before I packed the van away for winter.

Thanks! /pauric

Tue Jun 01, 2010 3:09 pm

This symptom can sometimes indicate a mainshaft bearing that is in failure mode. This bearing sits alongside 4th gear, so vibration isn't felt in other gears.

The VW mainshaft bearing and 4th gear reside in an area of the transmission that sees very little oil exchange, and so these parts are especially affected (overheat) if the trans oil level should go low.

Tue Jun 01, 2010 7:36 pm

Thanks mate, I'll double check the oil level but 2K ago it was right up to the filler plug. Is there any way to check/test/confirm that bearing is worn?

cheers /pauric

Tue Jun 01, 2010 10:13 pm

Short of pulling the front housing for a visual inspection of the bearing, check the oil drain plug. When the bearing begins failing, the gear teeth of 4th gear usually wear abnormally ... and the magnet can confirm this.

Wed Jun 02, 2010 3:42 am

Thanks again

Thu Jun 10, 2010 6:42 am

Just to follow up incase anyone does a search with similar symptoms

I spoke with Daryl at http://www.aatransaxle.com/ who has a good business case for taking money off me if I'm offering it and he said it didn't sound like a transmission issue.

"Sounds like a CV joint rather than the trans..I would look into pulling the axles and checking them first..they can be sneaky"

Which is what I will do, at some point. Might just pump them with grease first. Will follow up this thread with progress.

/pauric