Torque converters
Discussion
OK now I need to bone up on torque converters...
Regular readers may recall that my 2007 DB9 had what we thought was a misfire. It would stutter when accelerating from low revs, but only when the engine was fully up to temperature.Well, it did have bad misfires on two cylinders, and that was attended to (no thanks to the Aston specialist who couldn't get misfire counts, and thanks to Ian L and my local garage who did).
But the car still stuttered just the same. A former AM software engineer I happened to meet recommended an autoelectrician not far away, and after live testing it was finally diagnosed as the torque converter. They say I need a new one.
Presented with this information the dealer has offered to take it back and replace the TC (awaiting collection date). So hopefully we get to the light at the end of the tunnel. However, I am a curious person and whilst knowing nothing about gearboxes etc, am interested to know why it only happens after 30 mins (ie when the oil is up to temp). Logically I think it must have the wrong viscosity oil in, and just needs thicker oil. But I suspect it's not as simple as that.
Interestingly the car had a diff service before sale, when the car was only on 14K miles... perhaps an attempt to fix it, but got the wrong bit? Why else would you do that on such a low mileage car?
Regular readers may recall that my 2007 DB9 had what we thought was a misfire. It would stutter when accelerating from low revs, but only when the engine was fully up to temperature.Well, it did have bad misfires on two cylinders, and that was attended to (no thanks to the Aston specialist who couldn't get misfire counts, and thanks to Ian L and my local garage who did).
But the car still stuttered just the same. A former AM software engineer I happened to meet recommended an autoelectrician not far away, and after live testing it was finally diagnosed as the torque converter. They say I need a new one.
Presented with this information the dealer has offered to take it back and replace the TC (awaiting collection date). So hopefully we get to the light at the end of the tunnel. However, I am a curious person and whilst knowing nothing about gearboxes etc, am interested to know why it only happens after 30 mins (ie when the oil is up to temp). Logically I think it must have the wrong viscosity oil in, and just needs thicker oil. But I suspect it's not as simple as that.
Interestingly the car had a diff service before sale, when the car was only on 14K miles... perhaps an attempt to fix it, but got the wrong bit? Why else would you do that on such a low mileage car?
....because these transmissions have software which responds to many parameters, including temperature. A key component in any modern TQ transmission is the fluid itself. If you're under warranty and they're saying they'll replace the TQ then just go for it. Otherwise I'd be looking to see if there's another spec' of fluid which might settle the problem.
Some fluids can absorb water over time which changes their friction properties, causing clutches to slip. Replacing with a fluid that doesn't absorb water can be a potential fix. But check out the marque websites/forums to see if it's a familiar problem with a known fix.
Some fluids can absorb water over time which changes their friction properties, causing clutches to slip. Replacing with a fluid that doesn't absorb water can be a potential fix. But check out the marque websites/forums to see if it's a familiar problem with a known fix.
Thanks. The warranty is only an aftermarket one with a claim limit of £2K. The autoelectrician estimated the work to be £5K + VAT, so I presented that dilemma to the dealer. He said he could get a TC for £800 and fit it in a few hours so he said he'd do it.
I did ask the autoelectrician if a fluid change could fix it; he said not. His report concluded, after looking at engine parameters, 'Suspect gearbox issue analyse live data confirm fault with torque converter/gear box strip and inspect ref pos further damage'. He's very busy so has no motive to make unnecessary work for himself.
NB I'm assuming the diff doesn't share oil with the gearbox.
I did ask the autoelectrician if a fluid change could fix it; he said not. His report concluded, after looking at engine parameters, 'Suspect gearbox issue analyse live data confirm fault with torque converter/gear box strip and inspect ref pos further damage'. He's very busy so has no motive to make unnecessary work for himself.
NB I'm assuming the diff doesn't share oil with the gearbox.
Longy00000 said:
The service book on my vanquish S shows the diff oil was replaced at 3 years as part of a service.
May be just a good practice thing and also based on age not just mileage. FWIW the mileage at 3 years was less than 10k but was still done.
Thanks for the reply. The car had a FAMSH up to the year before so it seems surprising a small dealer would do work if he didn't need to.May be just a good practice thing and also based on age not just mileage. FWIW the mileage at 3 years was less than 10k but was still done.
Hi simpotwo - I was wondering if you had managed to have the torque converter work done and whether this has fixed your issues with the juddering? Im asking with a very vested interest as I think have exactly the same issue with my Rapide - all engine fixed done (PCV / coils etc etc) and no misfires but still the juddering. Any update would be amazing ! Thanks 
chrisbolton said:
Hi simpotwo - I was wondering if you had managed to have the torque converter work done and whether this has fixed your issues with the juddering? Im asking with a very vested interest as I think have exactly the same issue with my Rapide - all engine fixed done (PCV / coils etc etc) and no misfires but still the juddering. Any update would be amazing ! Thanks
Wow, lured out after 4 posts in 12 years, I'm honoured!The dealer wasn't confident with the diagnosis so sent the car to an Aston independent for a second opinion. They doubted it was the TC because they'd never known one to fail before. However AMDS confirmed a gearbox issue and they said the car probably needed a new gearbox. The dealer went for the cheaper option of an oil and filter change, but that didn't fix the judder, so the last I heard the car is waiting for a new gearbox and TC.
Although my 2007 car has only done 15K miles with FAMSH, the gearbox oil was found to be very dark and about a litre low. Whether a fault caused that, or whether the oil caused the fault I don't know. Official AM policy is to change the oil at 40K miles, but it seems likely that oil age was a factor here.
Was your car found to have significant misfires before all the coilpacks/plugs etc were replaced? It seems some people jump to that conclusion too quickly.
Edited by Simpo Two on Wednesday 11th May 11:28
Thanks so much for coming back so quickly - and really sorry to hear you still don't have it fixed - its so frustrating having such a great car that isn't driving quite right isn't it? I know - don't post much do I ? I do read lot though - just not much very interesting to say I don't think! Yes misfires were showing on AMDS (lots) - filters were oily and PCV failed so that was done but no improvement in juddering initially. Plugs / coils were initially changed (and misfires reduced) and the engine issues are now resolved from an AMDS point of view - but no improvement in juddering. I have to say that the symptoms do make you think 'gearbox' as its possible to drive around the juddering by using a slightly higher rev range / manually shifting - but I really want to get it fixed. I had the gearbox oil / filters changed and it got a bit better but the issue is still there. I guess I need to take a deep breath and get the gearbox checked out next !!!! Thanks again for the updates it's most useful. Just for info - mines a 2010 with 22k miles and full AM MD SH.....
chrisbolton said:
Yes misfires were showing on AMDS (lots) - filters were oily and PCV failed so that was done but no improvement in juddering initially. Plugs / coils were initially changed (and misfires reduced) and the engine issues are now resolved from an AMDS point of view...
Well that's progress anyway - one problem down, one to go chrisbolton said:
- but no improvement in juddering. I have to say that the symptoms do make you think 'gearbox' as its possible to drive around the juddering by using a slightly higher rev range / manually shifting - but I really want to get it fixed. I had the gearbox oil / filters changed and it got a bit better but the issue is still there. I guess I need to take a deep breath and get the gearbox checked out next !!!! Thanks again for the updates it's most useful. Just for info - mines a 2010 with 22k miles and full AM MD SH.....
Like you I found I could work round the judder - which would prevent acceleration - by changing down a cog or two. If your judder only starts after 20-30 mins then it does sound exactly like mine. Why didn't the people using AMDS look at the transmission too? Even a good diagnostics person with non-Aston kit can trace a fault to a gearbox. BTW was your gearbox oil the right level and colour, and when did you buy the car?Interesting point - been to both a Main Dealer and a well known indie - both clearly armed with AMDS yet neither of whom have checked out the gearbox.. Had the car a year - had a semi legal debate with the garage but no dice - sue me was basically the end result - so im over that (and the bills) and just want the thing to be running as I sure you do !!!
Interesting read.
I must admit I'm in a mess with my DB9.
Basically the car was working fine last year and over the winter I (stupidly) decided to replace the coils, plugs and PCV valves, and unfortunately when I ran the car it now has a rough idle and seems to run rich.
So I looked at everything I did and couldn't find anything wrong, very strange.
I used non genuine NGK coils & plugs so I thought that would be the problem so I bought genuine parts and changed them, no difference.....
So I thought there maybe a vacuum leak somewhere after all I did remove the PCV pipework to replace the valves, so I did a DIY smoke test, I found no leaks........
I have replaced the manifold gaskets and cleaned up the faces, new injector o-rings, cleaned the MAF sensors with proper MAF cleaner spray, cleaned the throttle bodies with new o-rings, still no difference.....
Nothing I have done has made any difference to the rough idle, so I've given up and now it's going to a top AM independent to get sorted, the car will have to be trailered as the MOT has now expired and as the car seems to be running rich my local MOT tester told me it will probably fail on emissions.
No fault codes on my Foxwell OBD reader.
Does anyone have a similar story? Has anyone had problems with bad earths/ wiring harnesses/ bad PCM's ?? Hopefully the garage will find a vacuum leak and they sort it.
Hopefully she'll be back on the road soon for some run-outs!!!
I must admit I'm in a mess with my DB9.
Basically the car was working fine last year and over the winter I (stupidly) decided to replace the coils, plugs and PCV valves, and unfortunately when I ran the car it now has a rough idle and seems to run rich.
So I looked at everything I did and couldn't find anything wrong, very strange.
I used non genuine NGK coils & plugs so I thought that would be the problem so I bought genuine parts and changed them, no difference.....
So I thought there maybe a vacuum leak somewhere after all I did remove the PCV pipework to replace the valves, so I did a DIY smoke test, I found no leaks........
I have replaced the manifold gaskets and cleaned up the faces, new injector o-rings, cleaned the MAF sensors with proper MAF cleaner spray, cleaned the throttle bodies with new o-rings, still no difference.....
Nothing I have done has made any difference to the rough idle, so I've given up and now it's going to a top AM independent to get sorted, the car will have to be trailered as the MOT has now expired and as the car seems to be running rich my local MOT tester told me it will probably fail on emissions.
No fault codes on my Foxwell OBD reader.
Does anyone have a similar story? Has anyone had problems with bad earths/ wiring harnesses/ bad PCM's ?? Hopefully the garage will find a vacuum leak and they sort it.
Hopefully she'll be back on the road soon for some run-outs!!!
chrisbolton said:
Interesting point - been to both a Main Dealer and a well known indie - both clearly armed with AMDS yet neither of whom have checked out the gearbox.. Had the car a year - had a semi legal debate with the garage but no dice - sue me was basically the end result - so im over that (and the bills) and just want the thing to be running as I sure you do !!!
AMDS is only as good as the person using it. The funny thing is that an Aston, well a DB9 at least, can be misfiring on all cylinders, and have a gearbox filled with treacle, but it won't give any warning lights or error codes.'We'll get it in and read the codes sir'
'Lol good luck, you won't find any'
Hello paul
Sorry to hear about your idle problem, having been a motor mechanic since 1975 ive been in that situation many times where its gone wrong with no obvious reason, you end up banging your head against it for hours checking and re checking until youve had enough then another mechanic walks up to the job and says " did you know youve put that on upside down"
Or whatever , then it so obvious you kick yourself.
I bet its something really simple and i hope you post it so we can all look out for it when doing , plugs coils etc.
I fitted ngk coils and the upgrade plugs 2 years ago and they have been fine.
Keep spannering!!!!
Craig
Sorry to hear about your idle problem, having been a motor mechanic since 1975 ive been in that situation many times where its gone wrong with no obvious reason, you end up banging your head against it for hours checking and re checking until youve had enough then another mechanic walks up to the job and says " did you know youve put that on upside down"
Or whatever , then it so obvious you kick yourself.
I bet its something really simple and i hope you post it so we can all look out for it when doing , plugs coils etc.
I fitted ngk coils and the upgrade plugs 2 years ago and they have been fine.
Keep spannering!!!!
Craig
Craig elam1 said:
Hello paul
Sorry to hear about your idle problem, having been a motor mechanic since 1975 ive been in that situation many times where its gone wrong with no obvious reason, you end up banging your head against it for hours checking and re checking until youve had enough then another mechanic walks up to the job and says " did you know youve put that on upside down"
Or whatever , then it so obvious you kick yourself.
I bet its something really simple and i hope you post it so we can all look out for it when doing , plugs coils etc.
I fitted ngk coils and the upgrade plugs 2 years ago and they have been fine.
Keep spannering!!!!
Craig
As Craig maybe suggests, is it possible one or more of the PCV valves are defective, damaged or installed the wrong way round?Sorry to hear about your idle problem, having been a motor mechanic since 1975 ive been in that situation many times where its gone wrong with no obvious reason, you end up banging your head against it for hours checking and re checking until youve had enough then another mechanic walks up to the job and says " did you know youve put that on upside down"
Or whatever , then it so obvious you kick yourself.
I bet its something really simple and i hope you post it so we can all look out for it when doing , plugs coils etc.
I fitted ngk coils and the upgrade plugs 2 years ago and they have been fine.
Keep spannering!!!!
Craig
I appreciate the comments, This isn't the first time I've done this job, the previous time the car ran perfect!!
But this time a rough idle, I've had the manifolds off at least 4 times since and triple checked everything, cross-checked with AM workshop manual and info on the web.
I've replaced all the components, genuine AM coils/plugs, PCV valves, gaskets all over again just in case any are defective, and still no change.
She's off to the specialist independent at the end of the week.
Has anyone had to replace the engine wiring loom?? that maybe the cause, apparently the reason why AM changed from 2-pin to 3-pin coils because the coils had earthing problems....
Anyone who's got any info on this please let me know, thanks.
But this time a rough idle, I've had the manifolds off at least 4 times since and triple checked everything, cross-checked with AM workshop manual and info on the web.
I've replaced all the components, genuine AM coils/plugs, PCV valves, gaskets all over again just in case any are defective, and still no change.
She's off to the specialist independent at the end of the week.
Has anyone had to replace the engine wiring loom?? that maybe the cause, apparently the reason why AM changed from 2-pin to 3-pin coils because the coils had earthing problems....
Anyone who's got any info on this please let me know, thanks.
Edited by paulrog1 on Sunday 15th May 20:16
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