Jerky downshift - Alfa Romeo Forum
You are currently unregistered, register for more features.    
Thread Tools Search this Thread
(Post Link) post #1 of 4 Old 30-08-10 Thread Starter
Status: -
AO Member
Join Date: Feb 2009
Location: Australia
County: New South Wales
Posts: 21
Hmmm Jerky downshift

I posted this before about 5 months ago but got no reply. Just wanted to have another go. I have a 159 2.4 JTDm Q-tronic. When the car downshifts from 4th to 3rd it's not smooth sometimes. It feels like a sudden jerk. It seems to happen when I'm driving and for example I go up a hill and the engine decides to downshift as the revs are getting low whilst I am still on the accelerator. I can also replicate it if I put it in manual mode and I downshift from 4th to 3rd whilst still pressing the accelerator. If I downshift whithout accelerating, it's smooth. All other shifts (up and down) are smooth as silk regardless of whether I'm accelerating or not. What could be the problem? Anyone else experience this?
doncarajo is offline  
Sponsored Links
Status: Lusting after a Peroni
AO Member
Join Date: May 2006
Location: Switzerland
County: Vaud
Posts: 433
Images: 15
I suggest you take it to the stealers and ask them to ensure the gearbox has the latest software updates. I did the same with mine as the car wasn't holding revs in manual mode...if I changed from 3rd to 4th under hard acceleration it then immediately changed to 5th.

Since they updated the software, the changes are smoother, fuel consumption is improved and the issues with holding the torque are gone
166lover is offline  
Status: - Update
Posts: n/a
Mine is not unlike yours yet at the same time it is different in many ways, what I mean is, mine sometimes has a really strong down-shift jerk when going from second to first below 40km, its as if the torque converter is just unloading too much before it transitions into the next gear and the tranny can not quite get the hang of speed, gear ratio and RPM based shifting to get it right!

One option - which is something I fully intend to get mainly for the gear performance enhancement as well as better overall performace and, to smooth out the transitions more; is to get the ECU remapped because this will also have a dramatic effect upon the Q-Tronic system as a whole and of course more so when compared to manuals.

Although just be sure that your fluid is the correct version and its replaced far before than what is stated - some say, that tranny fluid is invincible, or that it can lubricate its way through many sticky tight transitions without protection...all I know is, that it should be changed slightly before its due time if you are a DDriver and hammer (loosely used here) it home more aggressively than Captain Slow as such. Thats my take on things at any rate.
(Post Link) post #4 of 4 Old 01-09-10 Thread Starter
Status: -
AO Member
Join Date: Feb 2009
Location: Australia
County: New South Wales
Posts: 21
Thanks for the suggestions guys, unfortunately I don't know of any remap services here in Sydney Australia.
doncarajo is offline  

Go Back   Alfa Romeo Forum > Supported Alfa Romeo Models > Technical & Vehicle Assistance > Alfa 159, Brera & 946 Spider

downshift , jerky

Thread Tools Search this Thread
Show Printable Version Show Printable Version
Email this Page Email this Page
Search this Thread:

Advanced Search

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

For the best viewing experience please update your browser to Google Chrome