Why does my car jerk when shifting gears with an automatic transmission?

Answer 1

Either the fluid is low or you have a pressure problem. If the fluid is fine (see your manual on how to check it), then find a good shop.

===============================mine below

Ok,

This answer is relevant only for Automatic transmission vehicles , mine is a 2004, Nissan X-Trail T30 with 116Ks.

Car started to jerk when shifting gears. looked at the manual and performed a diagnostic and found a problem with a the Line Pressure solenoid (it comes as a 5 Solenoid pack, one being the Line Pressure Solenoid). Checked the status of the solenoid with a use of a digital multi meter (it was 4 Ohms or between 2 and 5 as specified by Nissan in its manual).

So we decided to do a rebuilt of the valve body (this is inside the transmission, normally on top of the Transmission Fluid pan, got a maze like built with chambers/cylinders for pushing oil with a pressure). When we were cleaning the valve body we noticed that some of the actual valves in the valve body were stuck to iron dust if general wear and tear )-- so the Line pressure solenoid spit an error( not that solenoid had a problem), so after the clean ( or rebuilt , in this case) car works fine.

What actually MUST have happened was coz of one main cylinders got stuck, it was not pushing the oil to effect a gear shift but when the vehicle increases its speed, TCM and TPS force anyway to move to higher gear and shift is done with out help from the stuck cylinder.

NOTE:

If u do this in a decent garage, cost around (all in Australian $) $2000, if u do it cost is under $350 but u do need a really good tool set with torque wrench($70.00) and GOT to be ultra careful in cleaning the valve body, don't use papers ...etc, if u leave scratch marks wear will eventually create the same problem. In my case we did it, bulk of the work was done my a friend of mine who is super in his handling of the complete project, so u need a helping hand.