Hi there,

I have a Volvo S40, AWD T5 2008 model. Recently when I was driving the car I was required to turn around. I pulled into a carpark and was coming to a stop, when I noticed a loud clunk/thump noise and the car turned off. I turned the car back on and and applied acceleration, it had high revs and very very slow forward movement. It did however, move in reverse just fine. I required the car to be towed, where I got my local service centre to look at it. They said the transmission fluid looked a little burnt but no codes were returned.

I had it towed back home and though I'd try driving it. This time, it drove forward completely fine. As my neighbour is a mechanic I asked his advice, he checked some electrical connections and cleaned them. Although hesitant to drive the car, I did. First I drove it around the suburbs and to the shops and it was completely fine. The next time the car drove for around 5-7km when the exact same thing happened. I was coming to a stop at the traffic lights and a loud clunk/thump was heard. Luckily I was next to a driveway and managed to drive the car in to a small carpark. I turned the car off and back on, tried to drive it forward however the car engine revved without moving and then turned itself off. I turned it on again and tried forward with no luck. Reverse was still working however, but it seemed ever-so-slightly strained.

I had the car towed home where it is currently sitting. From reading online I have come across the fact that the speed controller could be causing the issue, but I would like to know if anyone has experienced this? I previously replaced the gearbox with a second-hand one as my original had an issue with hard shifting and this was Volvo's recommendation. This gearbox ended up having the same issue, however I replaced the solenoids just outside the valve body and haven't had an issue since now, which is about 2.5years later. Could it be the solenoids? Please help, I really don't want to have to do a transmission rebuild and hoping it is something much more simple.

Thanks in advance

 

The clunk is the clue, I think. To me, it sounds like one of your axles or maybe driveshaft (to the rear wheel) has disengaged. It's not unusual for them to not be seated entirely if done by someone who doesn't work on Volvos a lot. When it slips out (you were probably turning hard and braking), the car will essentially send all the power to the "slipping wheel".

And yes, the vast majority of "bad transmissions" are really only "worn-out fluid" or "bad / gunked up solenoids". I did a video on how to change those (really not a difficult job - and a WHOLE lot quicker and cheaper than a new transmission). Still, most shops have only one answer for nearly any transmission misbehavior - replace the entire thing.

 

Hi habbyguy, thanks for your reply. I will definitely look into this. However, this only happened once while turning. The second time it happened I was going straight.

I did replace the solenoids about 2 years ago and the car has been going strong. Maybe something of interest, my neighbour replaced my engine head gasket as I had a coolant leak, however all has been fixed. He is the only mechanic I trust as I also get to see and learn from his work. Really knowledgeable and incredibly helpful.

Does this information add to the clue at all? To remove the timing belt the engine was lowered instead of raised, but I doubt this would cause any issues at all. I have noticed since the car has done about 210,000km that there is a ticking type sound coming from the engine but my neighbour said this was fine. I can record the sound if needed

I really appreciate your help as I would love to figure this out as soon as I can

 

I'm kind of baffled. If it was JUST the transmission acting up, that's one thing. But the fact it's also killing the engine is the key. I guess it could be electrical, so I'd check the ground strap(s) from the body to the engine / transmission. I can't imagine another electrical malady that would affect both the engine and tranny (losing a ground could do all sorts of odd things).

The other common link would be the torque converter. If it's failing internally, I could see it doing something like that (with the "clunk" being something coming loose inside the TC, stalling the engine the same way stopping with the clutch engaged in a manual tranny car would). Why it would work in reverse vs. drive is kind of mysterious, but the gear ratio is lower for reverse, so it might make sense.

And there are "normal ticks" from Volvo motors, particularly from the fuel injectors (which sound like little sewing machines). Doubt it has anything to do with the main problem though.

 

Whatever the case, you do need to look and see if your driver's side front axle is snapped in. You can look at that for free.

 

@habbyguy the first time it happened, I turned the car off and on, the engine cut out. After that I turned it on and it started normal. Mysteriously after getting my car back from the service centre and them saying the transmission oil looked a bit burnt, I turned the car on and it drove fine. So that's when I drove it an encountered the same issue. I was coming to a stop, heard that clunk, but managed to drive into a small lot. As I stopped to park, the engine cut out. Then same thing, I turned the car off and back on, then engine cuts out. Second time I turned it on the engine has no problem

I started the car yesterday and ran it for about 15mins without any issues of the engine cutting out. I'll look into the ground issue and also take the sump off the transmission soon to have a look at the solenoids. I'll also look into the torque converter, but will probably need my neighbour to help me with that when he has a free moment. Definitely hoping it's electrical as I feel that would be much easier to fix haha

@firebirdparts I'll take a look at that tomorrow and see if it's okay, thanks

 

hey all,

just posting an update in relation to this. I thought I'd see what I can try, which might narrow this down further. Haven't checked the front axel yet but I will

I thought I'd switch my gear selector to Manual Mode. I went from gear 1 to gear 2 and the car struggles when it changes, this is while stationary. I did this again and the car stalled. I thought I'd leave it for a couple days and try again. Today I just did the same, changed from gear 1 to gear 2, it struggles (same from 2 to 1). Tried again, the car stalls. Did this 4 more times and it happens each time. I thought maybe there is an issue with the gear selector? Hoping it's not the clutch packs. Does this give any further clues as to what this might be? More than happy to record a video if needed

 

Hi all,

Just providing an update with this

The driver axel is in fine condition. My neighbour replaced the transmission fluid today after finding that it was quite dark. The solenoids couldn't be removed so instead they were cleaned whilst in position. The car engages in 2nd gear manually fine now whilst stationary. It also drives!! So I will continue to keep an eye on things to see how they go, but it may have been a case of new transmission oil and maybe a small particle being lodged in one of the solenoids? I'm hoping things are fine now and will take it for a few test drives to ensure it is all good

 

New fluid can fix a host of issues. I'm not sure what was keeping the solenoids from being able to be removed (it's not difficult to remove them, IMHO).

But yeah - if the new fluid does fix the issue, I'd do one or two MORE drain-and-fills of the transmission fluid - using only the correct fluid, of course - to remove more of the original nasty black fluid. That's cheap and easy, and the best thing you'll ever do to keep your car out of the junkyard.