oh dear, I hope this wont be too expensive :(

[sagalout]

Just driving round town today and realised the car wasnt kicking down - in fact it wasnt changing gear at all. Parked up and reverse wouldnt select either. Turned the ignition off and restarted and it seemed fine again. Then drove home and the car doesnt seem to want to get out of 2nd gear (I think its 2nd - hard to tell) but does keep accellerating to higher and higher revs - just wont change up. Parked up at home and tried selecting reverse etc. All works but its quite a jerk which I never experienced before :/

Up until now its been silky smooth :/

 

[sagalout]

hhmm, interim update. Just tried that gearbox trick and its driving like a new car! Seems a lot nippier and the gearchanges are 200% better than I've experienced - absolutely seemless.

I'm not convinced its the end of the problem though. From reading other peoples posts about faulty MAFs my syptoms seem to point to this and I notice people have said it does seem to fix itself for a bit. Theres no doubt the reset has made a huge difference though - even if the MAF does end up being replaced.

Going to give it a run out later to see if the problem resurfaces.

 

[Parrot of Doom]

If you suspect the MAF next time it does it, unplug the MAF and see if theres a change in the behaviour.

 

[Ian B Walker]

Or check your Gearbox fluid, might just be a little low?

 

[sagalout]

Cheers guys. Its due for its next 99k service in about 600 miles so think I'll just bring it forward and get it in next week.

Just been for a 10 mile run and it drove beautifully, so fingers crossed!

 

[bibamus]

hhmm, interim update. Just tried that gearbox trick and its driving like a new car!

I`m intrigued, what trick is this?

Allan

 

[sagalout]

http://www.mbclub.co.uk/forums/showthread.php?t=19457

 

[Vlad]

If its a 5 speed box you may also have the infamous gearbox gremlins which tend to effect the electronic 5 speed boxes.

The problem stems from a dodgy gearbox seal which allows gearbox oil to weep out, which then travels down the wiring harness to the Gearbox ECU which it then invades and starts to cause all sorts of odd gear selection problems, loss of gears, especially top, and loss of reverse.

The only cure is a new gearbox ECU and replacement of the wiring harness and the gearbox seal.

 

[GIN51E]

If its a 5 speed box you may also have the infamous gearbox gremlins which tend to effect the electronic 5 speed boxes.

The problem stems from a dodgy gearbox seal which allows gearbox oil to weep out, which then travels down the wiring harness to the Gearbox ECU which it then invades and starts to cause all sorts of odd gear selection problems, loss of gears, especially top, and loss of reverse.

The only cure is a new gearbox ECU and replacement of the wiring harness and the gearbox seal.

Don't go that far just yet!

common problem is the pilot bushing 'electrical plug socket' on the Transmission 722.6 & 722.9 tend to leak and fill the plug up with oil, which causes a short in the electrical system which places the transmission into a limp home mode where it runs in 2nd gear,

simply replace the 3 o'rings and clean out the plug and all should be good.

it can also be caused by a fault in the Transmission control board which is located inside the transmission on top of the valve body, which sometimes requires replacement but the plug filling up with oil is the cause 90% of the time.

i have never seen the Transmission control unit causing a fault such as this. if you look under your car can you see oil on the transmission sump pan? otherwise unplug the connector from the transmission and you will likely see some oil come out.

 

[sagalout]

Well no problems with it today. If it was the problem above would it leak oil to the ground? The car is garaged and theres no sign of any fluids on the ground at all

 

[GIN51E]

depends on how bad the leak is, sometimes they can dump oil all the way down the underside of the car or the oil is just pooling up inside the connector and if you disconnected it then you would get some oil come out,

if its the controller inside the transmission you can sometimes get it to fault by twisting on the plug.

just about anything can cause these problems as the vehicles electrical systems are so advanced and sensative. i'm just telling you the most likely faults.