L322 8 speed box problem

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kermit_rr

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Mentioned previously in general chat but it's happened again so thought I'd start a thread.
A number of times (less so since oil filter change) if i slow down on the brakes to say 20mph then accelerate again, the gearbox would bang into gear with a solid thump, like engaging a dog clutch.
A few times I've been going downhill slowly, gone to accelerate and it's felt like it's revving freely in neutral.
Well it's just happened again.
Going down a steep hill, slowly with 1st selected and showing in the dash. Brake to navigate a sharp bend and the revs drop to idle. Still quite steep so i just let it progress under its own steam, foot off all pedals.
When the road opens up a bit, car going faster but revs still at idle. On the accelerator, nothing, no speed increase until suddenly bangs into gear and in at 1800rpm. Not the heavy thump I've felt in the past though.
Any ideas? There's no error codes
 
Mentioned previously in general chat but it's happened again so thought I'd start a thread.
A number of times (less so since oil filter change) if i slow down on the brakes to say 20mph then accelerate again, the gearbox would bang into gear with a solid thump, like engaging a dog clutch.
A few times I've been going downhill slowly, gone to accelerate and it's felt like it's revving freely in neutral.
Well it's just happened again.
Going down a steep hill, slowly with 1st selected and showing in the dash. Brake to navigate a sharp bend and the revs drop to idle. Still quite steep so i just let it progress under its own steam, foot off all pedals.
When the road opens up a bit, car going faster but revs still at idle. On the accelerator, nothing, no speed increase until suddenly bangs into gear and in at 1800rpm. Not the heavy thump I've felt in the past though.
Any ideas? There's no error codes
Does gearbox need a few more oil changes to make sure you have all new oil in it. Not one for additives but maybe a gearbox one. Used to be one recommended on here but forgot its name.
 
Whats the mileage mate? I'd be inclined to try a mega flush by bodsy then take it from there. Or even just have a chat with him, Google updates by bodsy

Edit
Did the trans adaptations get updated when you had the oil change?
 
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Is that the anti judder stuff? Think that's more of a band aid to the inevitable?
It's had one oil change but not a flush
Liqui moly do transmission cleaners, restorers and additives. Have a look at their range and see what you think. A few videos on the tube showing their use. I once many moons age used the engine additive in an old engine with improvements.
 
Whats the mileage mate? I'd be inclined to try a mega flush by bodsy then take it from there. Or even just have a chat with him, Google updates by bodsy

Edit
Did the trans adaptations get updated when you had the oil change?
Coming up to 108,000. Adaptations were done but didn't feel any difference, i thought you were supposed to?
Still got a couple of months warranty from when u bought it.. wonder if that's a possible route?
 
How long since the last change and was it the first?

I would be inclined to change it again before adding anything.

We don't experience anything like that (that we have noticed) but I often feel that I get engine braking sometimes when coasting downhill (TC lockup?) but can never really be sure but it feels like it.

Very rarely use the paddles though.

J
 
Not sure but maybe 2000 since it was done? Don't know before that which is why i did it. The oil didn't look bad.
The TC works fine on the flat, i can select d1 at a standstill and see the revs float until it locks up, no drama. If i let it slow down on the revs it will unlock again and i can accelerate at the point
 
Adaptations were done but didn't feel any difference, i thought you were supposed to?

Yeah I'm under the impression you should reset as well

I was always under the impression the adaptations should be reset only on major "mechanical" changes?

I wouldn't call a service that, do the adaptations get changed on the engine when the oil is changed?

The car will relearn after a few hundred miles "drive cycles" anyway, doesn't it?

J
 
I was always under the impression the adaptations should be reset only on major "mechanical" changes?

I wouldn't call a service that, do the adaptations get changed on the engine when the oil is changed?

The car will relearn after a few hundred miles "drive cycles" anyway, doesn't it?

J
Oooh I dunno then, maybe just on a megaflush? Mine weren't reset when I had simple oil and filter change and its no worse for it
 
The transmission is constantly adapting it will even adapt its line pressure to the old oil, and also due to changes in the tolerance of the internal parts, the fluid pressure and timing changes.

What the ZF 6 and 8hp transmissions do is to keep learning the shift pressure and timing values and adjust them accordingly by using the new values for the next shift. This learning is continuous as the values also change when the gearbox oil is changed.

Two important parameters in the operation of the gearbox are shift pressure and shift timing. This shift pressure and timing in the valve body of the tranny control the application of the clutch packs
As they age, their internals wear and the transmission fluid also wears due to heat and sediments. Because of changes in the properties of the fluid, like viscosity etc etc, and also due to changes in the tolerance of the internals, the fluid pressure and timing changes. The transmission control unit automatically does this adjustment and stores it in its memory continuously.
What adaptive trans do is to keep learning the shift pressure and timing values and adjust them accordingly by using the new values for the next application of shift pressure and timing. This learning process is continuous.

Long story short best have the adaptions reset whenever the oil is changed.. ;) :)

 
The transmission is constantly adapting it will even adapt its line pressure to the old oil, and also due to changes in the tolerance of the internal parts, the fluid pressure and timing changes.

What the ZF 6 and 8hp transmissions do is to keep learning the shift pressure and timing values and adjust them accordingly by using the new values for the next shift. This learning is continuous as the values also change when the gearbox oil is changed.

Two important parameters in the operation of the gearbox are shift pressure and shift timing. This shift pressure and timing in the valve body of the tranny control the application of the clutch packs
As they age, their internals wear and the transmission fluid also wears due to heat and sediments. Because of changes in the properties of the fluid, like viscosity etc etc, and also due to changes in the tolerance of the internals, the fluid pressure and timing changes. The transmission control unit automatically does this adjustment and stores it in its memory continuously.
What adaptive trans do is to keep learning the shift pressure and timing values and adjust them accordingly by using the new values for the next application of shift pressure and timing. This learning process is continuous.

Long story short best have the adaptions reset whenever the oil is changed.. ;) :)

So get them reset so the computermabob can learn the new conditions from a default setting and adjust quicker..? Fair play for writing that out!
 
So get them reset so the computermabob can learn the new conditions from a default setting and adjust quicker..? Fair play for writing that out!
Yes they reset the adaptions in the TCM to allow it to start afresh, there is a limit to what it will adapt to hence the need for a reset :)
 
I wonder if i should reset myself?
In the last 2000 miles or so, the change from 1-2-1 has got better and seems better when it's warm. It still thumps 1-2 every now and then.
Maybe i should do another oil change?
 
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