Just drove from Palm Coast to Tampa, FL, smooth, fast flawless until I get to the stop position. More research suggests Harmonic balancer or torque converter. But trans shows
no signs of dysfunction in any other gear, shift or speed. And when the brake is released and the engine idles it moves away slowly and the vibe disappears. It shifts smoothly at any speed whether using the sport shift manual system or simple automatic shift.
Harmonic B, most research claims that has the car warms up the rubber seal swells and softens thus reducing and eliminating vibration until complete failure. Most say the vibration becomes less as the car runs at normal temp. Not mine, the vibration is always there no matter what the temp, and it can start out very slight and then build to a very intense vibration the longer I sit in "D" brake engaged. AS soon as I shift into "N" the vibe subsides but doesn't disappear completely. I can't keep throwing money at it. ONE thought; do these X5, 3.0 engine mounts have to be Hydraulic? I have replaced engine and tranny mounts. The tranny mount removed was fine. Soft, not torn up or hardened and cracked. This is a real problem many have experienced. The engine
isn't vibrating erratically at idle. Plugs have been replaced. Intake boots replaced, MAF cleaned. Air filter replaced. Disa rebuilt and new.
Who knows ?? What the BMTrouble U knows?

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X5 3.0 AUTO -2001 - 238,000 miles