Jerky 6-5 downshift

max_k · 08-31-2019, 09:43 AM

Hi!

I suddenly got a real jerky downshift when shifting from 6-5.
I drove around for a while and hope for it to get better, it dit. But it’s still there.

I’ve looked at my adaptation values and could see that the B solenoid had 120ms fill time while the other got around -1 to 7ms. And yeah, that could matter because the B solenoid is active in gears 1-5.

And when i shift to 6th gear it was kinda slow, i felt the car slow down a little bit when 6th gear was engaged.

So i managed to change the oil and filter in my tranny. I took down the valve body and replaced the B solenoid as well. The oil was really bad, and i managed to get out about 7ltr so that was good!

After the change it got a little better. But it is very harsch when i do a kickdown from 8-5gear or any gear above 6th to 5 or less.

So the delay seems to be there yet.. When i Coast down to standstill the blue gauge for efficient dynamics goes away for a little bit. It is like is lost the gear for a little time and kicks in the new gear.

Now my B solenoid is in 36ms, so its better, but not good..
Am i looking for a new valve body?

The fault doesn’t feel mechanical at all. It is just that it doesn’t know how to shift anymore

It can do soft downshift when i coast in 6th gear and let it go down to like 1000rpm then give a little more throttle before it shifts down. Then i shift smooth.

The car is s 530xd 2012 with zf8hp70

And again, the fault came suddenly one day i were drivning.

Morebs4me · 09-12-2019, 07:12 PM

Did you reset adaptations?

Bmw doubles · 09-12-2019, 08:54 PM

Maybe unrelated but next step is replacing my transmission mounts with stiffer versions. You know when the trans moves you lose power and it feels jerky.

max_k · 09-16-2019, 03:10 PM

Quote:

Originally Posted by Morebs4me

Did you reset adaptations?

Yes. And now im back at about 120ms on my B-solenoid

max_k · 09-16-2019, 03:15 PM

Quote:

Originally Posted by Bmw doubles

Maybe unrelated but next step is replacing my transmission mounts with stiffer versions. You know when the trans moves you lose power and it feels jerky.

I dont think its the mounts, because my fill time is way above the limits for my B-solenoid. And the b-solenoid is active between 1st to 5th gear. Any downshift from 6th or higher to 5th or lower i can feel the jerk.

But when i’ve done a jerky downshift, and i let it shift up and then do it again it feels much smoother. But if i Cruise in like 8th gear for a while and do a kickdown its there again.

mashpotato · 10-06-2019, 12:33 PM

Parts are probably worn out. New valve body?

or rebuild https://www.sonnax.com/parts/4590-zip-kit

There are videos around on valve body rebuilds. If you go down that route you can use it as reference.

08-31-2019, 09:43 AM	#1
max_k New Member 1 Rep 9 Posts Drives: 330XiA 2006 Join Date: Sep 2011 Location: Northern Sweden iTrader: (0)	Jerky 6-5 downshift Hi! I suddenly got a real jerky downshift when shifting from 6-5. I drove around for a while and hope for it to get better, it dit. But it’s still there. I’ve looked at my adaptation values and could see that the B solenoid had 120ms fill time while the other got around -1 to 7ms. And yeah, that could matter because the B solenoid is active in gears 1-5. And when i shift to 6th gear it was kinda slow, i felt the car slow down a little bit when 6th gear was engaged. So i managed to change the oil and filter in my tranny. I took down the valve body and replaced the B solenoid as well. The oil was really bad, and i managed to get out about 7ltr so that was good! After the change it got a little better. But it is very harsch when i do a kickdown from 8-5gear or any gear above 6th to 5 or less. So the delay seems to be there yet.. When i Coast down to standstill the blue gauge for efficient dynamics goes away for a little bit. It is like is lost the gear for a little time and kicks in the new gear. Now my B solenoid is in 36ms, so its better, but not good.. Am i looking for a new valve body? The fault doesn’t feel mechanical at all. It is just that it doesn’t know how to shift anymore It can do soft downshift when i coast in 6th gear and let it go down to like 1000rpm then give a little more throttle before it shifts down. Then i shift smooth. The car is s 530xd 2012 with zf8hp70 And again, the fault came suddenly one day i were drivning.
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09-12-2019, 07:12 PM	#2
Morebs4me Private 6 Rep 70 Posts Drives: 550i Join Date: Apr 2017 Location: Florida iTrader: (0)	Did you reset adaptations?
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09-12-2019, 08:54 PM	#3
Bmw doubles Dream crusher 984 Rep 2,421 Posts Drives: Fast Join Date: Mar 2015 Location: westside iTrader: (0) Garage List 2011 535 [0.00]	Maybe unrelated but next step is replacing my transmission mounts with stiffer versions. You know when the trans moves you lose power and it feels jerky. __________________ 535i MIssion Performance, PS2, Helix HPFP Kit, Wagner FMIC, Spec 3 clutch, Steel SMF, Wolf Racing CP, UUC SSK, GFB dv, SprintBooster, Custom Dynomax Exhaust, M5 Sways, Eibach OE Springs, Koni Sports Adjustable, Custom Short Ram CAI IG: @bmwdoubles
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10-06-2019, 12:33 PM	#6
mashpotato Private 29 Rep 79 Posts Drives: '11 F10 N55 Join Date: Mar 2017 Location: Toronto iTrader: (0)	Parts are probably worn out. New valve body? or rebuild https://www.sonnax.com/parts/4590-zip-kit There are videos around on valve body rebuilds. If you go down that route you can use it as reference.
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