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gen4 auto box

Posted: Wed Jun 12, 2013 1:29 pm
by JohnG
My paj is my first auto and I just wanted to clear something up.
When going from "p" to say "r" or even then to "d" is it normal to have a noticeable jerk.
Well lets not say jerk but you can feel the car move when putting it in gear,or are you not suppose to feel a thing.
When i do it slow i usually feel the kicking in,and sometimes when i do it fast I feel nothing at all.

Re: gen4 auto box

Posted: Wed Jun 12, 2013 2:25 pm
by CATS
Sounds normal to me.

CATS

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Re: gen4 auto box

Posted: Wed Jun 12, 2013 2:26 pm
by 4ePajero
When the transmission is in Neutral "N" or Park "P" the torque converter is disabled.
This means that there is no mechanical connection between the (turning) engine, and the (stationary) transmission & rest of drive train.

Once you select a gear ("D" / "R"), the torque converter is engaged.
There is now a mechanical connection between the (turning) engine, and the (stationary) transmission.

The torque converter is now trying to turn the transmission, to give you 'drive'.
There is however a certain amount of 'slip', which is a function of the torque converter.
There will also be a certain amount of 'creep' (the vehicle moving slightly forward at idle rpm)

The amount of both slip and creep is a function of the design of the torque converter and transmission.
eg on the Aisin auto transmission fitted to my Touareg, the ECU prevents creep by applying the brakes when stationary.
It also prevents any 'roll-back' if one parks on an incline.

Long story short: Your transmissions seems to act 100% normal.

Re: gen4 auto box

Posted: Thu Jun 13, 2013 9:00 am
by JohnG
Thanks for the replies.no more worries then

Re: gen4 auto box

Posted: Thu Jun 13, 2013 1:36 pm
by RoelfleRoux
JohnG,
Sound normal to me.
Please also make sure you use the handbrake to keep the vehicle stationary when stopped. In other words: when you are done driving, stick the box in N and apply the handbrake to ensure the car will not move. Now you can slip the box into P and kill the motor. If you slip it across the R gate nice and quickly, then the torque converter will not engage and the movement will be "free". Enjoy your box, they are great.

Gerhard,
"the Aisin auto transmission fitted to my Touareg, the ECU prevents creep by applying the brakes when stationary"
I got to within an inch of buyng a new Treg about a year ago. I really enjoyed the test drive and we all know they are great rides, this function you mention really didn't suit me very well. I like the notion of being able to move in tight spaces by simply releasing the brake and crawling around. I hated having to push the load pedal to get it to move :roll: