Multitonic Gearbox Fault

[lojiuk]

This A4 has an erratic gear change almost like its slipping, the revs shoot up and more so when travelling between 40-60. In top gear the cars behaves. Have taken this to Audi who have diagnosed a fault with speed sensor and multitronic switch, new ECU required.

Question is where is the speed sensor situated?

I ask this as i have had this car from new (2002) and in that time has already had two ECU's fitted and a seven plate clutch fitted, luckily while this was still my company car for four years when i was clocking the miles travelling, (spent more time in the dealership than on the road)

The car is in great condition but Audi want £1200 pounds to rectify this fault which frankly on a car this age isn't worth putting the money into it. Is it worth trying to fit a speed sensor (i don't know where its fitted) first before condemning the ECU. And is the ECU worth sending off for repair?

Regards

Kev

[drpellypo]

Have you thought of checking the engine for faults? If someone has a multitronic they always seem to go straight to box issues. I had exactly the same issue as you and I replaced the n75 valve (which made a little bit of difference) and then took the turbo off and cleaned as the VNT was sticking. No more free revving.

[willsan]

Hello there , I have a multitronic problem too , after driving for about 15 minute the box decides it doesnt know if its in D or S so has a bit of a fit and then I lose all drive ,the PRNDS display flashes , If I switch it off and wait for 30 seconds and restart the car then usually the problem has gone , but it will re occur .

I got a chap that I work with to plug in his code reader and it came up with 2 faults ; output speed sensor , and the gearbox range sensor .

I did a bit of trawling on the internet and found that sometimes the wheelspeed sensors can cause problems for this box , one chap just took his out gave them a wipe and it sorted his problem .

unfortunately this did nothing to help my problem but its worth a go . I cant find anything about a speed sensor inside the box , maybe somebody on here has a better idea.

I decided to take the ecu out of the gearbox and have it checked by someone (BBA Reman can do this for about £30 ) it wasn't as difficult as I thought but i did have the use of a ramp .

I will let you know how I get on , for the time being I could do with some advice on how to re fill the box with oil ,so ifanyone has any ideas I am all ears .

oh your original question , I dont know if there is a speed sensor in the box but the wheel speed sensors are on the front of the hub / upright , whip the wheel off and you will see it quite easilly , you need a 5 mm allen key to remove it (and maybe a little wd40 )

hope this is of some use , sorry ,I am a bit nowhere today , shouldnt have had that last san miguel last night

Willsan

[lojiuk]

Aren't the speed sensors on the wheel the ABS sensors as well and surely if they are at fault would put a ABS fault on the dash?

There are no fault codes on the engine side, and Audi themselves have read the fault codes form the gearbox ECU.

If refilling the Gearbox is easy then let me know as would be tempted to take the ECU out as well and have it tested. Have seem ecutesting who will also test this part.

This will certainly be my last Audi, the missus has a Renault Megane diesel Auto (w/2000) with 166K from new, and has never let her down, perhaps German engineering ain't as good as we think and the French have overtaken them?

[drpellypo]

The torque sensors are on the wheel hub (behind the brake calipers) and are separate to ABS. My car was juddering really badly so I took these out and cleaned and then put back. Problem pretty much solved. Certainly it was a lot better. I don't know if there are additional speed sensors. The MT box is all electronics and complex at that. My next car will be a manual, but still an Audi because I still think they are comparatively very reliable cars.

[danclyon]

The torque sensors are on the wheel hub (behind the brake calipers) and are separate to ABS. My car was juddering really badly so I took these out and cleaned and then put back. Problem pretty much solved. Certainly it was a lot better. I don't know if there are additional speed sensors. The MT box is all electronics and complex at that. My next car will be a manual, but still an Audi because I still think they are comparatively very reliable cars.

Remember the MT box is now nearly 10 years old - so the electronics isn't that complex!!

In fact, overall, it's quite simple - and *relatively* reliable. It's just a few % that have problems....

D.

[drpellypo]

I do wonder that with regards to horror stories, whether it's just forums that are to blame for it's seeming unreliability. What is the life expectancy do you think? Mine is at 168k. Has had a clutch upgrade. Never had an ECU. Is now slow to respond for first few minutes driving and seems to hunt around for the right gear when pulling out of corners, junctions etc. This is intermittent though. Sometimes it does it, sometimes not, so I wonder if it's just a 'feature??'

[danclyon]

I'm not suggesting anything :) Mine died at just under 4 years old, thankfully still under warranty and was eventually replaced in full by Audi. I've done a lot of reading about the beasts over the last 18 months (as I came from an engineering background and am curious). I know that some on here have their beliefs that Audi is covering up known reliability problems etc (in fact the insurance assessor who came to look at my car after a recent accident, when I mentioned the noise that appeared to be gearbox related, his diagnosis not mine I should add, told me they wouldn't pay out as Audi had well publicised problems with the Multitronic!) but overall, against the number of units sold, for something that is a lot more complex than a manual - they are probably at about,or very close to the rate of failure they were expecting.

It seems the design has evolved from the original 6-plate clutch-pack with weaker hydraulics, through the 7-plate to cope with the torque, and now onto stronger boxes with even better oil-flow properties that seem much more reliable.

Having read a number of the studies done by the designers of the box (LUK) they suggest that they admit that the early designs were less than perfect, but if cared-for they are probably OK, and that the weak spot seems to be the hydraulics - in early designs they weren't quite shifting the volume of oil around inside at the right rates to ensure long-life.

They have since made a lot of refinements, but the ECU is still in a ludicrous location - and I cannot seem to see WHY in any of the studies, but they have adapted the gearbox to MUCH larger applications than wee-little passenger cars, being in use on HGV's now so pulling comparatively huge loads with awesome torque requirements, and the only real huge improvement has been in the hydraulics.

I love mine, and the wife has a Merc with the same concept gearbox in it. I've driven DSG cars from the VAG range and they are not a patch on the Multitronic. Long may mine last....and I will stick to a ~30k change interval on the Multitronic oil just to treat it with a bit of TLC :)

Cheers,
Dan.

[yaman]

Question is where is the speed sensor situated?

Kev

There's a wheel SPEED sensor on each hub.

There's a road SPEED sensor on the final drive.

There's a engine SPEED sensor (usually on the L/H rear of the engine block)

Take you pick, and happy hunting! :D

Regards
Jim

[blackchilliman]

Hello there , I have a multitronic problem too , after driving for about 15 minute the box decides it doesnt know if its in D or S so has a bit of a fit and then I lose all drive ,the PRNDS display flashes , If I switch it off and wait for 30 seconds and restart the car then usually the problem has gone , but it will re occur .

I got a chap that I work with to plug in his code reader and it came up with 2 faults ; output speed sensor , and the gearbox range sensor .

I did a bit of trawling on the internet and found that sometimes the wheelspeed sensors can cause problems for this box , one chap just took his out gave them a wipe and it sorted his problem .

unfortunately this did nothing to help my problem but its worth a go . I cant find anything about a speed sensor inside the box , maybe somebody on here has a better idea.

I decided to take the ecu out of the gearbox and have it checked by someone (BBA Reman can do this for about £30 ) it wasn't as difficult as I thought but i did have the use of a ramp .

I will let you know how I get on , for the time being I could do with some advice on how to re fill the box with oil ,so ifanyone has any ideas I am all ears .

oh your original question , I dont know if there is a speed sensor in the box but the wheel speed sensors are on the front of the hub / upright , whip the wheel off and you will see it quite easilly , you need a 5 mm allen key to remove it (and maybe a little wd40 )

hope this is of some use , sorry ,I am a bit nowhere today , shouldnt have had that last san miguel last night

Willsan

Hi,

How did you get on with BBA Reman as I'm having the same problem and have been advised to give them a go?! Were they able to repair the ECU?