# GM AF40 Gearbox



## CoOkIeMoNsTeR (Mar 6, 2011)

Hi guys :wave:

Soooo, I've bought a Vectra. I know, I know, I was drunk at the time and todays hangover was sponsored by 'old speckled hen' but even at around 00:40 hours this morning it sounded like a good buy just because of the money, £1500 for a 58 plate black SRi estate with the 150 1.9 CDTi engine and the AF40-6 tiptronic auto box and 148k otc.

Here is the fault, the car drives fantastic, and goes like the clappers, but when stationary in drive or reverse (worse in reverse) the revs drop and the car shudders and sometimes stalls. Put it in neutral and it stops, back into gear and it pulls away fine, you just can't hold it stationary in gear if that makes sense, but say if you pull up to a junction in drive or in manual mode and select a gear, say 1st, it'll shake and stall, but if you pull up and slot it into neutral it'll idle ok. Put it back into drive when you are ready to go and it pulls away spot on.

It's had a brand new gearbox fitted 13 months ago and is just out of warranty, the oil is new, and otherwise the box is great and it changes smooth and the manual mode is perfect, responded to my commands and was very smooth.

Someone suggested it could be a canbus fault in the instrument clocks which confuses the box (It tells you what gear its in) so that is one possible, the other in my mind could be the selector and the other is the ecu. There are no fault lights on the display.

Firstly, does anyone know which ecu it is? What's the part number etc? and am I on the right lines here or is there something I haven't considered? Surely it can't need another gearbox, it's only done 12k miles, it's not recon, it's brand new, I've got the bill for £3k here.

Anyone with experience of this box or Vx part numbers, your input would be greatly appreciated :thumb:

TIA :car:


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## bidderman1969 (Oct 20, 2006)

Bad earth for the gearbox ECU?

Has it always done since the new box? Did it do it before? How longs it been doing it this time? Just started? (If you know the history that is, or ask the garage that replaced the box, why it was replaced?)


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## CoOkIeMoNsTeR (Mar 6, 2011)

Thanks for that, according to the job sheet the box was fitted because the car would not engage drive and was deemed to have a faulty power control valve which is terminal on these things apparently. Box was fitted 10/5/12 @ 135,784 miles.

This fault has been present for the last 2k miles and 8 of the 13 months since changing it. That timescale is due to the car being auctioned off by the company who owned it and its sat around my friends yard ever since.

He changed the oil last week and took it for mot and the fault hasn't worsened but the oil change didn't improve things.

Despite the sit around, the egr is clean and the car goes very well indeed


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## CoOkIeMoNsTeR (Mar 6, 2011)

OK, it appears I've missed something.

I spoke to an auto transmission bloke today and he told me that the car should engage neutral when stationary, even in drive or reverse to reduce temps and improve economy or some such... until the driver gives a throttle input.

He thinks the car might be stuck in gear and won't engage neutral when the lever is put in drive or reverse, adding some weight to the theory of it being a computer problem, not a mechanical one and that the clocks or selector could cause it, and would be worth changing those before changing the ecu.

The other thing someone asked me is what about the torque converter? The answer is that it was changed with the box and surely if it was that you'd feel it complain when you move off? This hates sitting still, like it's in gear and wants to go, but the computer is saying no you can't move yet because the driver hasn't given an input, so you should be in neutral, but it doesn't appear to want to be in neutral, unless the lever is manually moved into neutral 

Oh, and the creep function is very powerful, given the slightest poke of the throttle, it would pull a house down, but leave it on its own and it will stall. Due to the DVLA being swines and not letting me buy a tax disc until next Monday because the car has no tax on it now, I can't drive it on the road till then, but when I do, I'll video what the car does to give people an idea :driver:

Any more thoughts? :speechles


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## mr jp (Mar 31, 2008)

Did you get this sorted mate? I have exactly the same issue on my Vectra CDTI Auto.


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## CoOkIeMoNsTeR (Mar 6, 2011)

PM sent :thumb:


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## Kimo (Jun 7, 2013)

Ooooh z19dth engine, need the egr valve and manifold replacing soon 

They'll make the car shudder too


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## CoOkIeMoNsTeR (Mar 6, 2011)

They do, but the EGR is clear and it's deffo the gearbox, shame, but meh. I thought it could be complicated in the end, I don't play with stuff I don't understand. So adios Veccy, you will not be missed :wall:


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## bidderman1969 (Oct 20, 2006)

Got rid then


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## CoOkIeMoNsTeR (Mar 6, 2011)

Getting rid :thumb:

mr jp and I have the same fault on identical cars, never thought it'd be the torque converter as it's nearly new, but it looks that way. I've got other cars and this one is getting in the way now, so I'll see if it goes. If not, I'll re-evaluate come the end of the listing


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