Hey jmr3, this is how you troubleshoot it. Drive your X5 in Sport mode (pushing your speed shifter to the left). If you don't feel the hesitation, it is FOR SURE your torque converter. I will tell you this one thing: If it is your TC, replace it as soon as you can. It will create more issue for your transmission and four time the expense if not fixed.

I learned the hard way by procrastinating on mine, and it messed up my transmission after sometimes. I got ride of my X5 because of that bad transmission.

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B-Boy

2001 BMW X5 4.4i
2004 Bentley Continental GT (Crashed and Sold)