I noticed this evening that the 300D has a vibration that seems to be coming from the rear of the auto. I checked the tire to see if it was flat, and it was not. I checked to see if the bolts holding the wheels on were tight. They were all very tight on ALL wheels just to be sure. Then, I took it on a test drive in different gears. In D, I started off without a kickdown, and I noticed in second gear that the vibration took place between 2-3K rpms, it went away after 3K rpms. After shifting to third gear, I could feel the vibration at 3K rpms, but again, it went away after 3K rpms. At fourth gear however, I felt no vibration while driving down the highway between 2.5-3K rpms. On neighborhood streets, I shifted into S, which had the same result as just accelerating without kickdown in D. But then I shifted into L, and at 2-3K rpms, I did not feel and vibrations like I did in second and third gears. So, are the vibrations coming from the rear in second and third gear at/around 2-3k rpms driveshaft problems, or do I perhaps need to have my tires balanced?
-Joe

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'81 MB 300SD, '82 MB 300D Turbo (sold/RIP), '04 Lincoln Town Car Ultimate

Sooner or later every car falls apart, ours does it later!
-German Narrator in a MB Promotion Film about the then brand new W123.