I bought a new 2008 GL450 in December 2008 without the test drive and noticed some issues with it the very next day. Reported to the dealer for the following issues:
1. Heavy vibrations
2. wind noise from back of the car
3. Noisy front passenger seat
4. Trunk wouldn't close properly
5. Weird noise from the Dashboard
6. Noise from the steering wheel
7. Weird noise from the left-front of the dashboard
8. Head light were pointing downward; couldn't drive at night time
9. Left passenger door won't close properly
It took numerous visit to the dealer service and after 3 - 3 1/2 years; they were able to fix
some of the issues but other remained. Currently have 38,000 miles in it and the service has asked to replace tires 3 times (original plus 3 new replacements) to get our #1 and #2 fixed but it is never fixed. Noise from the steering wheel has gotten worse and they are asking me to pay $2000 for replacing it. They are also asking me to replace left-front strut and pay $2000 for it.
I have complained to MB USA numerous times; they asked us to go to a different dealer but they were never actively involved in resolving these issues.