Thanks. In fact I called in with my local auto box shop this morning. The boss wasn’t in so I’ll call again tomorrow but the guy I was talking to said that if there’s something wrong with the TC, a fluid flush almost certainly won’t fix it.

Hopefully more news tomorrow.

Found this about Aisin Auto Gearbox Problems via Volvo site. - Well worth a read -

Describes Flaring and Rough/Delayed Gear Changing very well. It seems the type and state of the fluid is considered more important than the makers 'Sealed for Life' would indicate.

As I read it, poor lubrication can lead to early wear/malfunction of the valve body that controls the gear changes.

https://hortoncars.co.uk/volvo-news/volvo-...solutions/

My FL2 Metro MY14 is ok in this regard, but my previous FL2 XS MY11 used to 'Flare' on very warm days when on gentle throttle change ups. FL2 XS SD4 Auto 2010 2012-2017 (21k - 91k miles) (MY2011)
FL2 Metropolis SD4 Auto 2014 2017- (16k - 76k+ miles) (MY2015)

Last edited by IanMetro on 30th Jul 2021 8:42 pm. Edited 1 time in total

Thanks. An interesting read, and full of potential horror stories, but I’d have to say that - touch wood - my box displays none of the symptoms he mentions. It changes smoothly and without drama at all times. It’s just this blxxdy resonance/vibration at 1800 rpm.

I’ll see what my local gearbox guy says this morning.

I've noticed that those vibrations' amplitude are quite fuel quality dependent so, in my opinion, it's a vibration induced by the powertrain particularities, especially engine.
Meaning frequency resonances due to certain masses, fixings, etc. In the end, it's a diesel engine...
So don't throw money away for no (real) reason...
Just my 2 cents and in the same time I may be far removed from the truth...

I feel these vibrations @1700-1800 only and only when the tires are not properly inflated.

Well, my local auto gearbox guy said he’s 100% certain the problem is not with the box or torque converter. He advised against doing a fluid flush but interestingly he said that the usual drain and refill should require the best part of five litres whereas many posts on this Forum would suggest only about three and a half litres.

I’d agree with Alex about there being a connection between fuel quality and the strength/intensity of the vibration and in fact I filled up today with BP Ultimate which definitely seems to soften the vibration. But why does it not seem to occur with manuals? Could it just be that the autobox's comfort zone is 1800 rpm whereas if driving with a manual box the revs are likely to be kept much higher?

You're possible correct on the Auto box "comfort" zone as
I don't seem to notice much vibration in command shift as in full auto,
plus you may well be right regarding the quality of fuel,
I change from Shell V power to Shell over a year back,
and thinking about it I do believe the vibration has got worse (I did wonder if something was wearing)
from my next fill I'll go back to V Power, give it a month and see if there's any improvement.
Of course a lot could be caused by Forum Paranoia,  DAVE.
I.A.M. F1rst Driver.
Gone 2003 Discovery TD5 Auto,
Gone 1986 Defender 90 Station Wagon
Gone 1984 Range Rover 3.5 Vogue Manual.
Gone 1970 Series 11A/3 SWB 3.5 V8 Hybrid
Gone 1964 Series 11A LWB Van
Gone 1966 Series 11A SWB Van
Gone 1964 Series 11A LWB Station Wagon,

Fuel pressure sensor, mild misfire if feathering/indecisive on the accelerator at or approaching 1800 rpm? Could it be such a mild brief misfire that does not trigger a code? What I have read about this seems like it's similar to a brief misfire? It could be the fuel pressure sensor as well?

If the transmission specialist thinks it's not torque converter related did he have any ideas as to what it could be?

After reading some threads on a different topic by p_gill here and elsewhere, I am proactively replacing my i6 fuel pressure sensor......just some thoughts.

In my case there is no hesitation when driving at 1800 rpm, or when accelerating through it. It’s more like a resonance you’d get from a leaking exhaust gasket or vibration from a weak engine mounting. The transmission guy had no specific suggestions other than that it was, in his view, engine related, not gearbox.

But there seems no doubt that good quality fuel improves things, but doesn’t do away with it completely.

Glad to hear your gearbox man confidently ruled out the torque converter as like you Simon my gear changes are smooth and correctly timed, but still asks the question as to why autos seem to be affected. My brother has a manual same year as mine with 70 000 more miles on it and I’ve driven it and cannot replicate any vibration or resonance. I’m going to try and upload a video clip of my nearside driveshaft where it connects into auto box, this was ruled out by a “specialist”but see what you think as I thought it might be something bearing related and maybe if some others could check see if they are the same …

I can’t see how it can be driveshaft related - it occurs at 1800 rpm in any gear, and only at 1800 rpm. The torque converter is the only other thing that rotates at engine speed, apart from the engine, so if it isn’t it, it has to be the engine or its ancillaries. The fact that better fuel 'seems' to improve things might point to an injector issue perhaps but I really don’t understand diesels. Give me a pair if SU carburettors and I’m yer man but fuel injection? Work of the devil!

I’ve uploaded clip to YouTube search “ Freelander 2 driveshaft play”. take a look I’ve always thought it a bit excessive but if they are all like that then that’s ruled out too . Back on this topic again I’ll try to keep looking at what it could be but last time mrs got well peed off as I became obsessed trying to find a cure and spent a small fortune and hours and hours and got nowhere lol

I think this is an auto box issue and the reason you don't get it in a manual may be easy to explain

Try put your car in command shift but the same gear and speed that you would get the vibration
Accelerate gently for me I get the vibration
Try again but Press the Accelerator further down nearly to the floor no vibration for me

Its either a programing learning issue or maybe something called pulse width modulation where the torque convertor lock up is pulsed on and off to allow partial lock up and smoother running if the valve is worn in the valve body this won't work correctly

I have come across pulse width modulation on the 4l60e in my camaro that I use for drag racing I wrote the tune file myself when I modified the engine and uprated the box internals including a high stall torque convertor on my tune pwm is switched off completely and lock up is slightly harsher and I have had to adjust the lock up parameters so as not to lug the engine

After reading that volvo article it all made sense its possible that it could be repaired very cheaply parts wise by drilling out the worn valve body and fitting a sleave and new valve but the valve body still needs to be removed and thats not easy

To be honest, knowing nothing about auto boxes I don’t really understand your explanation. (I thought pulse width modulation referred to a type of solar panel controller!)

What I can say, however, is that it makes no difference which gear I’m in - the vibration happens at 1800 rpm. If I then press the accelerator, the engine simply goes above 1800 rpm and the vibration disappears.

pinhead wrote:

I think this is an auto box issue and the reason you don't get it in a manual may be easy to explain

Quote:

Try put your car in command shift but the same gear and speed that you would get the vibration. Accelerate gently for me I get the vibration.
Try again but Press the Accelerator further down nearly to the floor no vibration for me