Hello,
1982 300D gives me a knocking sound near the rear end or rear axels only while coasting. Under acceleration or maintaining speed is fine. Any ideas as to what it might be?

CV joints. Flex discs. Could be the carrier bearing, but that is further forward and the knocking from a bad one of those sounded like it was right under the center console when it happened to me.

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Whoever said there's nothing more expensive than a cheap Mercedes never had a cheap Jaguar.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 400,xxx miles
08 Suzuki GSX-R600 M4 Slip-on 22,xxx miles
88 Jaguar XJS V12 94,xxx miles. Work in progress.

The flex discs and carrier bearing are brand new.

Dry axles. Had the same problem. I thought it was a wheel bearing. Local indy filled the boots with grease. Problem solved.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Thanks,
I believe this is my problem. One of the boots is completely open and obviously there is no grease in there now. Any one know whats involved with replacing the boots and special grease?

I suggest you do some searching on replacing the axle. An open boot generally means your looking at a failing axle. I haven't had the experience (yet) but have seen plenty of posts to that point.

Others, more experienced, may join in with advice.

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83 300d - 390k