Dodgy speedo

[Graham]

While killing the remains of my tyres tonight on a fast tight left hand curve, (get toyos tomorrow ) my speedo started tripping out, it would sit at road speed then drop to zero, then back to road speed, then zero. Speed also affected it, the faster i got the more erratic the needle, then while chilling at slow speeds its ok mostly. When i changed the rear diff mount i nipped a sensor wire which sits on the top back of the diff, the wire didnt break, just squashed a little. Could this cause the fault as it has been 2 weeks since i done the diff mount. If not what do you think it could be?? Any help would be much appreciated. Why does this car always need something on payday, i only want a month-a single month- when i dont have to spend a penny on her, she is very high maintenance at the moment .
Graham

[s2driveruk]

hmm sounds like a dodgy sender but thats on the gearbox or maybe a poor connection to the speedo itself. mine sticks at certain speeds in hot weather or with the heater on full blast but not managed to resolve it as yet...can be a real PITA but at £170 to replace i can live with it for the moment!!!!

David

[Vagsport]

Have found in the past it's either the speedo sender (the one on the differential cover) but this tends to be stone dead, no reading at all. Erratic readings tend to be the rotating magnet pressed onto the differential gear itself. They crack, at low speeds, it's fine but a higher speeds, the crack is opened up by centrifugal force, hence the on / off effect.

Changing this requires removal of the N/S driveshaft and differential cover.

Siena

[Beetie]

On my 96my A4 it went like that and it was the sender on the gearbox.I *think* audi charged me 120 quid to get it changed, so id give VAGparts a ring mate!

[Graham]

Cheers, went out last night to friends and it was fine, went for my new tyres today and all was fine. Hope it stays that way.
Graham

[Beetie]

Cheers, went out last night to friends and it was fine, went for my new tyres today and all was fine. Hope it stays that way.
Graham

I know what its like! Mine was tempermenatal, until i went to oxford, and it gave up completely on the M40!

[Greenm3]

I have just done a large trip today and had problems with mine it kept sticking.....
BUT i think it is also about 10mph to high.......i will explain the circumstances.....i took it off the clock for a while about time enough to gain an extra 10mph could this have cause it? I assue there arent many people who have encountered this?

[S2 Ant]

There are 2 senders of some sort on the gearbox, one on each side, both plugs are fairly easy to get at on the ABY engine'd cars, not sure about how difficult the actual sensor would be to change tho.

[Vagsport]

2 senders?? I only know of 1

Siena

[S2 Ant]

hmmm there are def 2 plugs on my box, one on each side, as when it was removed the first time we unplugged one but not the other.

Im 99% sure there was 1 on each side.

[Graham]

Well i drove up to Newcastle last night and it was fine, no problems at all, i wonder if my problem is only when i go stupidly fast as i was when it first cocked up. But up to now all is still fine- i hate intermittant problems as they always occur when you least want them to.
Graham

[Greenm3]

Same thing here Graham my problem is gone and now the speedo seems accuracte again ......well dont fix it if it aint broke

[Vagsport]

The plug on the other side (off side) is the reverse lamp switch.