Harshness of shifts is controlled by vacuum level. Low vacuum=harsh shift. You could have a vacuum leak. You can use a MityVac to monitor the level of vacuum going frm the vacuum control valve on top of the back of the IP to the transmission modulator at various accelerator positions. You can then compare those numbers to the info on the transmission vacuum thread.
85's have an additional componenet in the transmission vacuum system--it's the blue flying saucer type thing on the left inner fender. It's called a vacuum amplifier I think.

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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