What is a known problem with the BMW 2002-2008 E65 E66 and also I have heard on the 5 series BMW. What most people think is a transmission problem really is the Guibo Joint or also known as the Flex Disc or U Joint or the Universal Joint. The symptoms you hear are very similar to a transmission going bad. The Guibo is located underneath the passenger and drivers seats where the drive axle connects. Right next to that is the BMW E65 E66 transmission so during rough shifts you think it’s the transmission. On my BMW E65 when pulling up to a stop sign and during downshifting from 2nd gear to 1st, I will get a jerk almost a slam, immeditilty you think it’s your transmission, so as most folks do they 1st replace their transmission oil thinking it’s a little low. I did this and replaced the Transmission Filter and put fresh Redline D4 fluid in, unfortunately the problem was still there. When replacing the Guibo you’ll be under the car, so if you haven’t replaced your BMW E65 E66 Transmission Filter or replaced the Transmission Oil then this would be a good time to accomplish this. Watching the video below I talk a lot more about the Guibo Joint aka Flex Disc and show you what it looks like and a new one and a bad one. I will be doing this full project soon, so stay tuned. Thank you for spending your time with us here at DiyE65E66.