Gearbox/drive/brakes?

[Vince]

We have a problem with our 2.8 v6 4x4 auto, would like to know what you guys think...

 

First of all the car passes the MOT, only advice was some play in track rod ends, then we go off on holiday driving up and down the 25% hills of the North Devon coastline.

 

The first fault we noticed after 5 days of this treatment was abrupt gear change, going up from 1st to 2nd was quite agressive. The sort of jolt you get from a manual if you let the clutch up very quickly.

Then we noticed that sometimes there was a grinding noise and vibration on the brake pedal during braking. The last fault is that the ABS light came on.

 

The mechanic that the AA sent out jacked up each of the wheels, could not find anything wrong with bearings or brakes (maybe some sign of worn disks scratching at the rim), but the garage that did the MOT is reliable in my eyes, so I don't suspect worn brakes after one week of the MOT. The AA mechanic suspected the ABS warning might have been because of the jolt during gear changes, but wasn't sure why a transmission problem might be felt on the brake pedal.

 

The AA took the car back home for us. Today we tried the car again. Gear changes all seemed ok, and there was only one rumble from the brakes.

 

A friend who usually knows his stuff suspects grit in the oil blocking the valve chamber (don't know exactly what that means, other than an oil change) but does this explain all the symptoms?

 

The car is booked in with a transmission specialist, but what do you guys think?

 

Got the following from VagCom...

 

VAG-COM Version: Release 409.1-S

 

Control Module Part Number: 021 906 256 AE

Component and/or Version: MOTRONIC M3.8.1 AT V01

Software Coding: 00001

Work Shop Code: WSC 00000

1 Fault Found:

01165 - Throttle Body Control Module (J338)

20-10 - Malfunction in Basic Setting - Intermittent

 

 

 

 

VAG-COM Version: Release 409.1-S

 

Control Module Part Number: 1J0 907 379 H

Component and/or Version: ABS/EDS 20 IE CAN 0001

Software Coding: 12812

Work Shop Code: WSC 00020

1 Fault Found:

00283 - Front Left ABS Wheel Speed Sensor (G47)

35-10 - - - Intermittent

 

Could not get a reply from the auto gearbox.

 

Vince.

[seatkid]

Just guessing....

 

00283 - Front Left ABS Wheel Speed Sensor (G47)

35-10 - - - Intermittent

 

This is what is giving the grinding/vibration - the ABS is being triggered by a dicky signal from the sensor. Check the connector to ABS sensor in the wheel arch - unplug/clean replug. Also clean up the area where the ABS ring /sensor is on the hub (mud/debris). Try a forum search for ABS problems which go into more detail.

 

01165 - Throttle Body Control Module (J338)

20-10 - Malfunction in Basic Setting - Intermittent

 

This is what is causing the abrupt gear change - again likely a dirty connector - find the thottle body position sensor and clean the connector. Basically the Auto box ECU is thinking the throttle is being floored occasionaly when its not. Could also be caused by a loom/connector problem to the autobox, which a number of people have reported. Again try a forum search.

 

First of all the car passes the MOT, only advice was some play in track rod ends

Funny... I was told on 2 seperate occasions by 2 seperate garages that "any play in a steering joint is an MOT failure"!

Edited May 21, 2007 by seatkid

[Vince]

Hi Seatkid,

 

Thanks for the suggestions. I will take a look at these, but I will take some persuading that you are right on the gear change being the throttle sensor.

 

The gear change isn't occuring at the wrong time, it's happening at the right time, but it's not the smooth change like you normally get. It's more like it's been thrown into gear, and there is a definate jolt of the car and thump from the gearbox/drivechain. Just like you get in a manual if you let the clutch up far too quickly.

 

My friend suggests that auto boxes do this when they engage the next gear before disengaging the last one. Then when the previous gear does drop off there is a sudden take up by the new gear, and thus the jolt and thump. I am paraphrasing slightly, he talks of brake bands rather than engaging gears.

 

Having said all that, all it seemed to do last night was one of the bad braking sessions, nothing obvious from the gearbox.

 

Vince.

Edited May 22, 2007 by Vince

[Vince]

Update on this issue...

 

It appears to me that these are two different issues rather than one very badly broken gearbox.

 

Since getting back home we have taken the V6 out a couple of times. The gearbox does not seem to be playing up now, but the ABS is, so I have a new ABS sensor (drilled the other one to it's demise) and new disks/pads, will fit these tonight.

 

I did not like the look of the back of the disk on the side where the ABS was unhappy, rather than a nice flat surface caused by wear from the pads, there is a nice curved profile suggesting the the pad is unevenly wearing tangentally to the axle.

 

So I need to work out if the gearbox is now ok.

 

Vince.

[mumble_bee]

heya vince,

 

I too have the 4x4 v6, my story goes like this...

 

2 weeks ago, I had a course in highwycombe...

course started on a friday evening.. and I live in luton....

I knew going down the M1, round the M25 and up the M40 would be choca...

so I multimapped the SHORTEST route instead.. which took me across about 40 miles of hills and what shall hitherto be referred as EVIL TERRAIN !!!!..

 

my gearbox was also "apparently" playing up on these up down wind around and shake it all about roads....

however soon after my return on sunday night... bombing it across the motorways.. all was good

hasnt given me trouble since...

 

I've since decided that the gearbox was trying to be clever and hold the gears longer because it thought thats what I needed...

tut tut...silly thing.

 

wish you luck.

[Vince]

Hi Mubble,

 

High Wycombe isn't far from where we live!

 

Two people off forum have suggested that these might be 'learning' gearboxes, does anyone know for sure?

I did suggest to the mechanic that the AA asked to come out to us, that I wanted to do a 10 minute battery break, but he didn't go for that.

 

I am not sure if the ABS is fixed, as I did not clear the error code. Thought all was ok when I drove off and the light went out, but it's been going on and off, so I have now reset the fault code and will keep an eye on it. All the nasty noises have stopped with the new disks and pads.

 

Thanks for those who have helped.

 

Vince.

[Vince]

Update on my woes...

 

The wife's galaxy has just come back from the Gearbox specialist.

The Gearbox module will not talk to my VAGCOM or their system, so we cannot ask it how it is, but it seems to be fine, any ideas? Should I give it 10 minutes without batttery?

 

And I could do with advise please on the ABS, I have changed the disks, pads (both sides front) and ABS sensor on the front left where the fault was reported.

I am still getting some strange noises from the front followed by ABS warning light with the same warning about front left ABS sensor.

 

Should I reseat the ABS module? Where is it? (Near the radio head unit is it?)

 

Vince.

[turk90210]

re the ABS have you checked all the obvious ie, wheel bearings ect and is the mating surface where the sensor fits is it clean,(the castle like surface on the drive shaft) or even the cvjoint. I was thinking of these because of your strange noise as you call it. the ABS sensor runs next to the castle like surface by a very small gap, if there is any movement in the gap it can give you a false readingand bring the warning light on

Believe it or not it has been know for a new tyre on 1 side and a worn 1 on the other to bring the light on as it see's the 2 wheels running at different speeds

[bigdaddy]

Not had this problem myself, but reading other posts, it is common for the abs ring on the cv joint to come loose from its mount, this would make a hell of a noise and set of the abs light

[Vince]

Good points there!

 

The two front tyres were replaced two weeks ago, and the MOT was just days before that, so I would hope the bearings are ok.

 

The ring that the sensor picks up from was attached and 'seemed' ok.

 

All are possible explanations, I suspect the noise is the ABS false firing and am contemplating a 10 minute battery disconnection, to do a reset.

 

Vince.

[hotleaduk]

Had the same VAG-COM abs fault on the left abs sensor, also abs light constantly on, bought a new one from ebay for

[mikej]

Had a simlar problem to this a while back turned out to be the ABS ring had a hair line crack in it , almost impossible to see untill the ring was washed down . Every so often it would open and cause the ABS to kick in , new ring sorted it out , may be worth a try .

[Vince]

Thanks for the tip Mike, I will take a look at that option. The rings can be replaced then can they?

 

Vince.

[Vince]

Had the same VAG-COM abs fault on the left abs sensor, also abs light constantly on, bought a new one from ebay for