Hi There,

I opened the box up and couldn't see anything particularly obvious. It's all surface mounted and riveted into the box so you can only get to one side.

I have a 'new' one comming from A8Parts with the right code. BL It should be a plug and drive part +++

Will see what happens when it arrives

Lee

Hi There,

10 minutes work this morning to swap the Gearbox ECU and it seems I have gears again. Haven't taken her for a test ride yet, but I believe I am up an running!

Lee

Hope its a good result. I have learnt a lot from this thread though I hope I dont have to use it. +++

Fingers crossed for you fella, I do love a happy ending +++

Take the positives from all of the unnecessary work, in future you'll tackle gearbox problems with no fear at all ;)

Well done Lee thats excellent news! :respekt::yippee:

Hi There,

Well I went home with the novelty of working gears last night. I've noticed a bit of pulsing with things, but that could be down to having low oil as doing the filling procedure on axel stands, even at a fairly low level will result in it being out. Will be getting it topped and checked tomorrow on a ramp.

In doing this I've learnt a lot and cleared some debris from the gearbox and changed the oil which are all good things. I think if I was in a similar situation, i'd trace the box out first, however I didn't know that info until later.

I think If I had given it to Audi they would have charged a couple of hundered diagnostics and then a lot for the TCU, so i've come out pretty reasonable!

Thanks,
Lee

Hi there,

AND.......More bad news. Drove down to London on Saturday night and almost got to mys destination, slight over rev and [PRND432] comes up. Limp mode and 5th gear only. Parked up at destination. Came back and it had cleared. Pull away and limp mode after a brief bit of driving. Got home in 5th *SIGH*

Vagcom just gives me a 17114 - Incorrect Gear Ratio P0730.
I did also notice an engine speed sensor error intermitant, but cleared it.

Having a search and read i found this http://forums.audiworld.com/showthread.php?t=1755643

Now doing a quick bit of testing with vagcom.

state Eng Spd Input Spd Output Spd Gear
Idle 750 0 0 1M
1st brake 800 768 0 1M

Scoping while trying reverse and forwards, gets *VERY* little in the output speed regardless of input. You get 25-100rpm maybe. And when the input speed reaches 1500-2000 it hits limp mode.

I'm thinking that output sensor is out of whack as if you were getting slippage i'd expect to get more spiky readings of the output and a larger reading???

So.....Where is the output sensor on the S8 as it isn't inside the gearbox as per the BMW/LANDY

Lee

The transmission output speed is taken from a target wheel on the Torsen unit carrier by an inductive sensor.

http://i260.photobucket.com/albums/i...pse7104ab4.jpg

http://i260.photobucket.com/albums/i...ps05a5204d.jpg


There’s also an output speed sensor on the LH front driveshaft but I assume that’s for the speedo.

http://i260.photobucket.com/albums/i...ps45598539.jpg

http://i260.photobucket.com/albums/i...ps2ce05d8c.jpg

Unlike the 5HP24, the wiring for the output speed sensor of the 5HP24A is separate to the main transmission wiring loom i.e. it doesn’t pass through the 16-pin connector.


The input (turbine) speed sensor sits on top of the valve block assembly, of course.

http://i260.photobucket.com/albums/i...ps24b7b5ae.jpg

Phil

Phil,

Much useful information yet again :D

However having an extensive play with VCDS last night in the carpark i'm less convinced it is a speed sensor, though quite what is happening I am not quite sure!

After clearing errors and starting the car, limp mode is not engaged and everything looks fine.

You can get reverse nice and smooth, monitoring the sensors and input is high (800+) output is low (0/25rpm).

Changing to 1st with the brake and it's fine. Releasing the brake, no problems, but you don't really creep forwards like normal. Input is still high and out low. Adding gas very slowly and you get to 1200-1500 with still almost nothing on the output and then it hits limp mode. It's like it never even trys to engage 1st or actually move out of 5th!

Driving home in 5th last night I carried on monitoring and the input and output speed were both fine, which then says to me that it is not the speed sensor (in fact the output was often higher than input, which I guess is gearing).

I can check the solinoids and the power to them with the software if anyone has any ideas ???

Lee

Have you checked the oil level yet?

That would be the first place to start before you go digging deeper.