Car jerks when put in drive every morning
#21
One thing to consider is the very thing that makes the ZF 8-speed such a great performance transmission is that it does have quick, firm, and decisive shifts. Traditionally, automatics were referred to a "slush boxes" because the shifts were just that, "slushy." You may also have noticed that in hard acceleration in Dynamic mode, the shifts are also much more firm. That translates into faster acceleration.
In short, there's no doubt this automatic is a different animal from what most people are used to, but the symptoms described by all here are normal. I don't perceive it as bothersome at all, but human perceptions are usually all over the map.
In short, there's no doubt this automatic is a different animal from what most people are used to, but the symptoms described by all here are normal. I don't perceive it as bothersome at all, but human perceptions are usually all over the map.
Last edited by Foosh; 11-22-2015 at 12:48 PM.
#22
foosh I'm glad your car doesn't give you whiplash every morning. Rather than trying to tell us that what were feeling is normal would you consider that there could be an issue with some cars. In fact theres a recent TCM software fix for MY16 XE and XF cars to address "concerns about shift quality selecting D from stationary" so they are still tweaking this allegedly perfect transmission.
Maybe we should try to narrow it down to a vin range and see if theres any correlation.
This is my 8th Jag (4th with a ZF box) and I think the gearbox in my particular f-type is slower to downshift and worse behaving than the 3 speed GM box they used to put in the V12 XJS.
Maybe we should try to narrow it down to a vin range and see if theres any correlation.
This is my 8th Jag (4th with a ZF box) and I think the gearbox in my particular f-type is slower to downshift and worse behaving than the 3 speed GM box they used to put in the V12 XJS.
#23
foosh I'm glad your car doesn't give you whiplash every morning. Rather than trying to tell us that what were feeling is normal would you consider that there could be an issue with some cars. In fact theres a recent TCM software fix for MY16 XE and XF cars to address "concerns about shift quality selecting D from stationary" so they are still tweaking this allegedly perfect transmission.
Maybe we should try to narrow it down to a vin range and see if theres any correlation.
This is my 8th Jag (4th with a ZF box) and I think the gearbox in my particular f-type is slower to downshift and worse behaving than the 3 speed GM box they used to put in the V12 XJS.
Maybe we should try to narrow it down to a vin range and see if theres any correlation.
This is my 8th Jag (4th with a ZF box) and I think the gearbox in my particular f-type is slower to downshift and worse behaving than the 3 speed GM box they used to put in the V12 XJS.
And BTW, that wasn't my description of the ZF auto in the F-Type. Every one of the dozens auto journalist reviews I've seen have singled out the exemplary nature of the transmission. I've also heard people complain about harshness in the Porsche PDK in 911s and the DCT in BMW 3/4 series cars, but usually not from people looking for max performance.
Last edited by Foosh; 11-22-2015 at 02:40 PM.
#24
#25
I've been reading this thread thinking my FTR is nothing but smooth as butter... I do live in TX though and last night was the first time I ever even saw the snowflake icon in the dash. Any possibility that all of this is related to temperature?
#26
I do get what some people are calling a "jerk," but I don't perceive it as problematic. As I said above, I think this is a classic case of differences in perception. Or, in other words, "beauty [or not] is in the eye of the beholder."
Long before I signed up here and started posting after I'd taken delivery of my F-Type, I was lurking to try to gather as much info as possible while researching the car. In the more than two years of reading virtually every single post on this forum, I can't recall this ever coming up before.
Heaven knows, we've seen complaints about just about everything else.
Last edited by Foosh; 11-22-2015 at 04:43 PM.
#27
#28
here's a video from this morning.
after the revs die down (30 seconds in) I select D - 1.5 second delay and the car lurches forward with a squeak. Then I select neutral and D again and no jerk - just a feeling of it pulling.
FWIW ambient temp in the garage was over 60F (it's spring here) so I don't think freezing temperatures are a factor.
after the revs die down (30 seconds in) I select D - 1.5 second delay and the car lurches forward with a squeak. Then I select neutral and D again and no jerk - just a feeling of it pulling.
FWIW ambient temp in the garage was over 60F (it's spring here) so I don't think freezing temperatures are a factor.
#29
#30
#31
My theory is, that it's stored energy from contracting and flexing of all the metal parts. Generally, you put it away hot. So all the mating components mesh together smoothly. Ambient temperature is irrelevant. It gets hot when driven, cold when not. As they cool, the clearances tighten up. Also, did you try disengaging the P brake prior to see if there's a difference? That's one more point of stored energy, essentially, doing the same thing but also involving all the suspension unbuckling. You get a similar effect when disengaging the parking brake on a hill.
As to new vs. now, that's probably more to do with a better friction connection between both the parking pad and rotor as well as transmission components. Less slip as they've been worn in. Again, just a theory.
As to new vs. now, that's probably more to do with a better friction connection between both the parking pad and rotor as well as transmission components. Less slip as they've been worn in. Again, just a theory.
Last edited by MagnumPI; 11-27-2015 at 01:58 PM.
#32
Couple of observations:
You have to go through 'D' to get to 'S' and you end up in the same gear either way - so that wouldn't (and doesn't) make any difference to the jerk.
Having the park brake applied or not makes no difference (my garage is dead flat so there's no strain on the brakes or parking pawl from gravity). Also selecting 'N' while it's warming up (half push forwards) to release the parking pawl makes no difference.
You have to go through 'D' to get to 'S' and you end up in the same gear either way - so that wouldn't (and doesn't) make any difference to the jerk.
Having the park brake applied or not makes no difference (my garage is dead flat so there's no strain on the brakes or parking pawl from gravity). Also selecting 'N' while it's warming up (half push forwards) to release the parking pawl makes no difference.
#33
#34
#35
Are you sure TXJagR? You might be right, but it's strange that they write this about the rain mode:
"Rain/ice/snow mode. Use in slippery road
conditions. Selects 2nd gear for driving away on level
ground. Moderates engine response and modifies gear
change strategy to ensure maximum possible traction is
achieved. This mode must be deselected when no longer
required."
"Rain/ice/snow mode. Use in slippery road
conditions. Selects 2nd gear for driving away on level
ground. Moderates engine response and modifies gear
change strategy to ensure maximum possible traction is
achieved. This mode must be deselected when no longer
required."
#37
Yep Arne, 2nd gear is the default in mine too. Makes me laugh that it's called an 8-speed box, I presume 1st is exclusively reserved for starting from a standstill on an insanely steep hill?
#38
And in manual mode I usually always start in 1. even though I have noticed that it allows you to start in 2. as well.
I don't have any jerks when selection D on startup when cold though, but I do remember that my previous Touareg did that. And that had an 8. speed ZF autobox as well.
It did have 1. gear as default when starting though
#39
#40
I'd love to be a fly on the wall when that happens . I doubt there is any technical abnormality, just the normal differences in human perception.
I feel it first thing in the morning when the engine is cold and in a higher rev mode, but my description of the symptom that bothers a few folks is a firm shift into D at higher revs. If you wait several minutes until the engine is near normal temp and drops down to the normal warm idle rev, it doesn't happen, but that's completely unnecessary. I can reproduce the same thing on any automatic transmission by increasing the revs slightly in neutral before shifting.
The shifts are also very firm at high revs in dynamic mode during hard acceleration, to the extent it will chirp the tires under some circumstances. I love that.
Since the same ZF is used in so many makes and models, I'm quite sure it could be programmed out, but I suspect that might have other undesirable performance consequences, which I'd prefer to avoid. It also doesn't bother me in the slightest.
I feel it first thing in the morning when the engine is cold and in a higher rev mode, but my description of the symptom that bothers a few folks is a firm shift into D at higher revs. If you wait several minutes until the engine is near normal temp and drops down to the normal warm idle rev, it doesn't happen, but that's completely unnecessary. I can reproduce the same thing on any automatic transmission by increasing the revs slightly in neutral before shifting.
The shifts are also very firm at high revs in dynamic mode during hard acceleration, to the extent it will chirp the tires under some circumstances. I love that.
Since the same ZF is used in so many makes and models, I'm quite sure it could be programmed out, but I suspect that might have other undesirable performance consequences, which I'd prefer to avoid. It also doesn't bother me in the slightest.