Does the shudder happen mostly when the engine is cold or after a long drive in traffic? And does the GLE have air suspension, since that can add its own clunks over bumps? Also curious what the dealership quoted for the diagnostic, so people here can tell you if it’s really that high.

Check the manufacturing date on the sealed box before they open it. A 55D23L that has been sitting in a hot van or warehouse for six months has already lost measurable capacity before installation, fresh stock from the last two to three months is what you want for full lifespan in this climate.