Loz1970

PowerShift knock question.

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A question for Edge drivers with the Powershift Automatic. I’m getting a audible knock sound under acceleration after breaking or coasting, the knock doesn’t happen when pulling off, nor when accelerating through the gears, however, when at speed if I coast(foot off the accelerator), or break (I’m assuming the clutches disengage at this point), then when I apply the accelerator next there is a knock as if the clutch is not engaging smoothly (like dumping the clutch pedal if I had one), but it doesn’t cause a jolt or anything, just the single knock sound. I’ve never heard this when I had a Mondeo with PowerShift gearbox, so I’m wondering is it an AWD drivetrain thing. I’ve been to the dealer with it, and they’ve said it’s a characteristic of the gearbox which I can accept, but doesn’t sound right. As I’ve got nothing to compare it to, I thought I’d ask you guys. Just want to be sure before my warranty runs out in June. Also, I should mention it’s just had its 36k mile full service including gearbox oil change, but it didn’t make a difference, the knock is still there.


It’s easy enough to test, turn your radio off, coast, press accelerator, it sounds like I’m knocking my centre console with my knuckles.


If I’m not alone, I’ll be reassured it’s nothing to worry about.

 

 

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Wow, nobody can answer my question. I'm a key worker, do about 100-150 miles a day, my warranty is about to end, it has been fully serviced at a Ford dealership via my service plan. I'm assuming that the knock/clunk is unique to my car due to no replies.

 

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I would take the car to a specialist Ford dealer and ask them for advice. When new clutches are fitted they come with a serial no that allows the technician to run adaptive learning calibration software. 

Do they need the clutch serial no to run the test program. You might not have this.

I've never owned an automatic, but this does not seem right. Has a seal leaked in the transmission allowing some fluid on the clutch, changing the bite point ? Probably at low speeds the effect is too small to notice. A calibration might fix it. 

If you just take  it back to the original dealer they will do nothing and say it is normal to save them any costs. Hopefully someone else can give you better advice.

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Hi Kevin, thank you for your reply, really appreciated. I would have hoped the dealer would know what the issue is and sort it under warranty at no additional cost to themselves, they’re a main Ford consumer and commercial dealer. I don’t want to name names here, but I find I’m having to research my findings and present back to them to get them to look at it rather than fob me off which is a stress in itself.

From what I’ve learned so far, is that disconnecting the battery will not help, and only resets the PCM, it’s the TCM that needs reprogramming “Learning” as you mentioned.

As the issue is only apparent when resuming from coasting, I started to look at that and the only information I can find regarding a “coast clutch” is for the torque converting gearbox.

A lot of my driving is mixed, stretches of motorway, then urban areas, it’s here where it’s more noticeable, with all the stop, starting, crawling, breaking etc.

I have no oil leaks at all, bone dry under the car, it drives lovely, and changes through the gears perfectly smooth, the knock\clunk is only apparent when resuming from coasting in any gear, so it must be between the final transmission and the drive, almost like a solenoid on/off engagement rather than a smooth clutch engagement. The dealer has already had my car in for it, and gave it me back saying it’s a characteristic of the gearbox, and I’m no expert on the Powershift/AWD mechanics, but I could fathom the schematics if I could find any relating to the Edge drive system.

I’m off this week so I have time to dig deeper, I’ll try speaking to a few dealers, as I’m guessing it doesn’t matter which dealer I take it to whilst under warranty, although I have a service plan with this one in particular.

Thanks.

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Can you drive another car of the same type from a dealer and see how that drives. If a similar car drives without issues I would not be happy having kind that knocks when shifting.

The clutch has springs in it that should absorb any knocks. If the springs are in a daisy chain and the spacers have too much slack then the clutch might bit and travel before the springs start working. You need to look at the clutch design to see how it works with the springs.

I think the least the dealer could do is get the clutch re calibrated. If they say it can only be done when it is fitted then that's not an option. I would push them to swop out the car if you think there is a problem. I think the problem is a waring sign of thing that will get worse. A knock is not a good thing.

 

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Some garages use scanners that read the vin no and can clear he adaptive tables.

Select, service, transmission, clear transmission adaptive tables. The transmission then re learns the bite points as the car drives. This should improve how it works.

Your dealer should be able to do this, if they can not swop the car. If it says the same swap the car.

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Tried this morning when I went shopping. Didn't notice any knocking or noise of any type when doing what you said. Closest to any noise like that is when the fuel tank is half full and you break or accelerate momentarily and the fuel sloshes around a lot. When parking and you jab the breaks, the sloshing produces quite a knock sometimes but not really related to what you're mentioning.

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Thanks guys, it's not the fuel in the tank, I'm very familiar with that sound, this is knock from the front of the car, doesn't sound like an engine mount either.

I've recorded it, hopefully you can listen to it, should be valid for 7 days. Sorry about the SAT NAV voice and chirping birds, but you can clearly hear the knock.

Hopefully the URL below doesn't get deleted...

https://send.firefox.com/download/ac66fabc7e221e66/#c473r9NNKsqGMivrq3P4uQ

 

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That doesn't sound good. I dealer diagnostics will show an error code, but i think there is a mechanical problem there.

Was this there when you first drove the car?

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Hi Kevin, I don’t believe so, however, since Brexit and now Covid I drive a lot with the radio off, as I got sick of listening the news, and I guess that’s when I started to notice it, so it’s been there for about 7 months now, probably longer.

I think the knock has got worse over time as I can now hear it with the radio on, I forgot to mention during winter when cold, the knock is not very noticeable until the car has warmed up, in this weather it’s there from the get go.

I’ll try the dealer again, just not looking forward to the conversation and the rigmarole all over again! I was hoping to confront them with some anecdotal evidence from other Powershift owners.

 

Many thanks.

 

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I cant hear your recording but I don't have any knock when accelerating from coasting. I specifically listened out for it today with the radio off. good luck with your investigation. 

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