BMW E60 automatic shudder: torque converter lock-up slipping
What causes the E60 automatic shudder?
Usually the torque converter lock-up is cutting in and out at a certain speed and rev range (e.g. 70-90 km/h at a steady throttle). The cause is usually in the gearbox mechatronic unit, i.e. the hydraulic control unit, for example worn accumulators or valve body, or in a worn converter.
What usually fixes the shudder?
An oil change helps only briefly. A more lasting fix is a rebuild of the mechatronic valve body or replacing the accumulators. The solenoids can be replaced by removing the mechatronic unit; the whole gearbox does not need to be taken apart. Replacing the converter alone hides the fault only for a short time.
Does an additive put in the gearbox help?
An additive such as Shudder Fixx can improve the friction of the lock-up plate and remove the shudder for a while. It does not fix a broken mechatronic unit or a burned converter. If the fault continues after two bottles, the cause is elsewhere.
Is slipping at low revs normal?
Moderate slipping in 1st and 2nd gear below 2000 rpm is normal, and the converter locks up only in 3rd-6th gears. Excessive, uncontrolled slip causes a fault code. When cold, high revs before a bigger shift are normal.