Gearbox help needed from england..

Hi everyone sorry for the english, i posted the below on an old thread while trying to send a email to a forum member ( sorry couldn't read the german) So I now have found my way around the forum a little bit and thought I might get a better response if i posted in the right place ..Hope this is ok......

Hi everyone thanks for the warm welcome....
1999 2.5 Acv. Bought the van with a faulty gearbox so i bought a very low mileage ( 1000km) gearbox and torque convertor which had been reconditioned. I had the gearbox and convertor put in but its still not quite right. When i get to 55mph it changes down a gear and the revs go from 2 thousand to 2.5. I also get odd random gear change..

If i plug the van into Vagcom i sometimes get a 01192 ( torque convertor lock up clutch..intermittent) fault..I was getting this fault with the other faulty box and convertor. I can't believe i have been unlucky enough to have 2 bad convertors...

I have taken it to various people and they are convinced it isn't a faulty box or convertor. The van drives very nice through town at low speeds..

The last person i took it to has been working with Autoboxes for 50 years, he plugged the van into a laptop and checked everything, he is 99% sure that the ECU is faulty as it was even giving strange random readings even while the van wasn't moving...The potentiometer etc were all ok...

So my question is what is the difference between all the Ecu part numbers...The one in my van is 01P 927 733 AK, I can get an ECU which ends 733 BS but i can't work out if they are all different and if the all work with other vans..

The van is fitted with an extra oil cooler for the box ( it onlys gets to 98 degrees after a 100k journey) so heat isn't a problem..

I think i am nearly there with this box, I have set the shift pattern to 00007 but it still feels like it is struggling on the autobahn...

Thanks very much for any advice this looks like a really good forum...even though i can't understand most of it........

Anthony

Hi,

Zitat

01192 ( torque convertor lock up clutch..intermittent)

this happens when the N91 valve is closing to slow. In my car this mainly happens when the oil at the gear box is above 110 C° but can also happen when the valve is blocked for a short time.

A typical additional effect for N91 Problems is that sometimes, special if you reduce the pressure on the gas pedal, the clutch inside the tourque converter close not smothly, it close from one moment to the other and the car gets a push for a short moment, the engine speed to tourque converter output speed is reduced in one second from round about 1000 U/min to 0 U/min.

The effect is visible at goub 7

"look up clutch slip slipping"

but hard to reproduce ... when this error occure the control unit moves into error mode and the tourque converter clutch is not closing anymore. After the engine restart the error mode is disabled and the tourque converter clutch will close again.

Zitat

01P 927 733 AK

this is the same controling unit I have ... the 99 model "without" CAN bus ... all new automatic control units are only availible for the 2000/1/2/3 model (having CAN bus) ... you can not upgrade the control unit ... only if you upgrade the engine control unit and the Instrument control unit to "CAN"

Kind regards

Frank

Hi frank, thankyou for the information, so do you think my problem could be the gearbox ECU or should I try something else.. I think I would be very unlucky to get the same problem on 2 different Convertors.( I had 01192 on the old convertor as well). Sorry i don't understand the n91 thing..

I just want my van to work correctly and be able to cruise on the autobahn without sounding like a screaming banshee...

How much do Ecu's cost in germany, i have seen one for sale here in England but at £175 euros I think it is a little expensive, If i was sure it would fix my problem then I would purchase no problem..

Thanks again

Anthony

Hi,

it is not the ECU (Elektronic Control Unit) it is the mechanical control part where all the valves are mounted:

I do not know the english word, the German is "Schaltschieberkasten" you can see at the picture. In this "unit" all the electrical controlled valves are mounted and the valve "N91" is controling the clutch inside the torque converter.

The valve is not simply schitched "on" and "off" to opne or close the clutch, the valve is "modulated" by a PWM signal to close the clutch "soft". Over time it can also happen that the mechanical parts which are shifted by the electrivcal valve part are damaged. You can see the parts out of my gear box where the internal aluminium part is partly silver and does not control the clutch very precise anymore.

My recommandation is to replace the "Schaltschieberkasten", I will do the same also soon. The lifetime of this unit is round about 200.000 km and the unit will cost 500 €.

Kind regards

Hi frank, thanks for that, why would this part have failed on a reconditioned box?? or is a part that dosen't get reconditioned....is the n91 a big job ? does the box have to come out etc....

Is it not possible that the ECU is sending the wrong signals to the box, the guy who looked at the box with his computer said the ECU was sending all sorts of crazy signals even when the van was not moving.

thank you very much for the help, your english is very good..

Anthony

Hi,

the N91 can be changed without disassambly the gear box from the car. Here you can see how simple it is to get acess: Automatikgetriebeöl wechseln

The mechanical unit which contains all the valves can easily be exchanged too, the tricky part is the flex foil. The foil has to be handled very carefull or replaced.

Zitat

Is it not possible that the ECU is sending the wrong signals to the box,

You can make a simple test:

- reset the error memory of the gear box ECU
- go to to group 5 where you can see the oil temperature and the selected gear: 0, 1H,2H,3H,3M,4H,4M
- drive carefull and increase the speed to check if the gear box is switching in following order: 0, 1H, 2H, 3H, 3M, 4M
- you typical have round about 2250 U/min engine speed if you drive 100 km/H at 4M and the engine speed is hard connected to the car speed, this "M" is standing for "clutch closed" in 4H "hydraulic mode" the tourque converter is in his not hard connected to the car speed and if you increase the engine speed the car speed will follow with delay and you will have more than 2250 U/min at 100 km/h if you increase the speed.

If the gear box is switching in this order: 0, 1H, 2H, 3H, 3M, 4M the signals from the ECU should be fine.

To get the "error" you can drive in a way where you increase the gear box oil temperature to 110 °C or 120 C° by going up and down between 40 km/h up to 100 km/h serveral times. When the gear box is starting to switch: 0, 1H, 2H, 3H, 4H you should find the error code stored in the ECU

If you reset the error code in the ECU the gear box will start again to close the clutch and select also 3M and 4M as driving modes. If you will see such a behaviour the ECU should be fine. The ECU is measureing the tourque converter input speed and output speed. In the mechanical mode (1M, 2M, 3M or 4M) the difference between the input speed and the output speed should be round about 35 U/min up to 60 U/min sometimes 0 U/min. If the difference between in and out is to big the error will be noted in the error memory (fault code). My understanding is that the software of the ECU is to critical and special when the gear box is at a higher temperature the clutch is not closing fast enough for the ECU software. It can be that a later software version is more tolerant ... but this software is not availible for the "AK" ECU ...

Zitat

I didn' know, that the clutch will be triggered with a pulse-width-modulated signal

The gear box "oil pressure" is controlled by PWM signals and the torque converter clutch. VW says: modulation valves: N93 (system oil pressure) and N91 (tourque converter clutch)

Zitat

would this part have failed on a reconditioned box??

this part is typical not replaced if you get a fixed gear box, typical the clutches to select the gears are replaced by new ones and the tourque converter is replaced.

Cheers Frank

Hi frank, thank you very much for the time you have spent helping me, I will try to do the tests..

Do you have part numbers for the N91 , mechanical unit and the flex foil, I have tried to find a flex foil before but couldn't find any infomation anywhere, is the N91/mechanical unit worth getting out of a broken box or is it a new only purchase...

Is the n91 easier to replace on its own or as a whole with the mechanical unit...

Thanks again...

anthony

Hi,

you can get these parts in the US: follow this link

Zitat

Is the n91 easier to replace on its own or as a whole with the mechanical unit...

the N91 parts are not so expensive and you should try them. If the new parts at N91 do not help you can still change the complete unit.

Kind regards

Frank