While the wagon is getting some TLC, I have been driving the SD. Today when coming down a long hill (maybe 15 degrees) As always, I noticed that with my foot removed from the accelerator, the speed held steady. Curious to see what the cause might be, I slipped the trans into neutral and she started speeding up significantly.

That would seem to point to the transmission and or the engine that either by design or problem, is causing engine braking.

Given the high compression both in term of ratio and PSI, is it a normal engine braking effect?

Also noted on the SD as opposed to the TD, you can let your foot off the brake on level ground (after a complete stop) and it will not creep forward. The same holds true for being on an incline (nose up), the car holds steady if you take your foot off the accelerator.

If by moving your foot slowly you remove what feels like free play in the accelerator pedal (maybe 1/4" to 1/2") the car moves forward...release the pedal and you can feel the power to the wheels drop off. To me, this function seems to be designed / engineered into the trans and controlled by vacuum.

Thanks in advance for any input.
Don

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1980 300TD-T (82 Turbo and Trans) 159,000 Miles "Jackie-O"
1983 300SD 272,000 Miles "Aristotle"
1987 Jeep Wagoneer Limited - keeps the MB's off the ice and out of the snow
1994 BMW 530it