My 2001 S40 2.0T 5 speed auto gearbox failed a month ago. I'd pulled in for petrol and after filling up and restarting, the gearbox just made banging noises and the car only crept forward at a snails pace. The revs would rise as if against a resistance then it would bang and move forward a couple of inches. It would reverse normally. Other symptoms were that the yellow arrow didn't show when selecting a low gear and after a while of trying, the engine management light came on. When selecting a forward or reverse gear, it came in with a thump but it didn't creep forwards in 'drive' as it would normally. Overall it felt really bad. I tried different things for about an hour but I had to leave it where it was and the next morning it went to Volvo on a truck. They couldn't find anything wrong at first but after driving it around it started to do the same thing again.

They changed the gearbox and it's been fine for a month but it's just done the same thing again with the banging and hardly moving forwards. I'd just returned from a long drive and restarted after only 5 mins. That is interesting as the last time it broke was after restarting without the car standing for long. This time the fault did clear after a very short time and drove ok so I didn't get to check for any other symptoms.

It doesn't seem to make sense it should do the same thing with a different gearbox and I'm worried that I can't trust it. Any ideas about what could be wrong? The local Volvo garage didn't seem to know what was wrong last time so I'm not confident they will have any better ideas now.

Do you happen to know if they checked the clutch?I would also check the axles.
We gon't have 5 speed S40's here in the U.S. that I know of.But that would be normal stuff to look at for a problem on a manual car.

I didn't know automatics had clutches. What could be wrong with the clutch or axles that wouldn't show up in reverse as well as in drive?

I did get you a little wrong when you said 5 speed I thought manual.But either it is in the trans or the axles.There is moving parts in the inner joing and outer joint.They might be slipping going foward and not backwards.

Thanks for the suggestions Tech but that still wouldn't figure with it feeling like there is resistance to moving forward. If there was something slipping it would still creep in drive as normal. Also, what the yellow arrow not showing suggest? It seems to me to be more like some valve or solenoid inside the gearbox not activating. I don't know much about auto boxes but I can't understand how the fault is appearing the same when it's had a new gearbox.

The only other thing I could thing of is that maybe the trans control module is getting hot and messing with the signal.It is kind of hard to tell not being there.

Ok, thanks for the idea. I take it that this trans control unit is not part of the gearbox then?

Iy is seperate from the trans but has alot to to with how it shifts and drives.That is weird that 2 diffrent gear boxes do the same thing.That why im thinking computer or wiring.

Ok I'll suggest it to the guys at the garage. Thanks.

Keep me posted on the progress.