Since there are often questions about tachometers and retrofitting, wanted to post pics of an 85, where they pull the signal from the transmission, and a pre-85, where it is pulled by the hall effect sensor from the harmonic balancer.

Old style, believe this one was dated July 83:


new style, dated feb 85:


note the new style has three pins, not two.

If the tach in an 85 isn't working, an earlier one can be used, but must be wired through the hb sensor and a tach amp and old style harness be used.

An older car can't use an 85 part afaik.

All cars, including 85s have the hb sensor, need to look at my 81, but I think that includes 240s.

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Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1985 190D (169k)
1991 350SD (113k)
1991 350SD (206k)
1991 300D (228k)
1993 300SD (291k)
1993 300D 2.5T (338k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (265k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)