My T4 sounds like a woodpecker lives under the bonnet......

[pblucas]

I have an AUTOMATIC 1999 VW T4 2.5tdi van. Generally in good condition and in last 12 months have had new altenator, started motor and cam belts. All else good till last few weeks. I have an intermittent knocking noise coming from the off side front. It doesn't appear to have any pattern to it i.e. turning left of right doesn't affect it. nor is it always there. It is intermittent, comes and go without rhyme or reason that I can work out and the best way I can describe the sound and rate is that it sounds like a woodpecker is hammer against something metal. That said the noise is speed dependent. it is a slow knocking to begin with and increases to full woodpecker rate as van increases speed. Have put van in neutral whilst moving and noise still present. Also doesn't seem to be load related as can occur on flat going up hill or down! Anyone got any ideas?? Thanks.

p.s. I have also developed a shuddering at the threshold between 3rd and 4th gear. It's an auto box and doesn't seem to want to change at 40mph or 1800rpm which is just about the time I feel it needs to go into 4th/top. Is this a simple auto box chip problem or something more serious?? Could the two faults be related??

Thanks again.

Pete

[Rph1973]

I read on here that it is the servo or it is the servo if when you are standing at traffic lights and hear the knocking sound press the brake 2 or 3 times hey presto noise goes. I done this other day andit worked

[Brian Considine]

It comes & goes on my T4 - AFAIK it's the vacuum pump.

[tom1]

It comes & goes on my T4 - AFAIK it's the vacuum pump.

I have this in my 2.5tdi metallic taping sound was told by mechanic slight wear in hydralic lifter 4 tappets ,but was not to worry about it untill i satarted losing power,which hasnt happend.

[pblucas]

Thankks for the feedback guys. FYI the sound has currently dissappeared for the last few weeks so fingers crossed!! :-)