I have recently purchased ( I will be the 3rd owner) a 1986 300sdl. I have owned a couple of VW deisels before. This car had 125,000 miles on it when I got it and was in near-showroom condition. Or so I thought. After about $2500 worth of mainatinence and parts replacements ( ALDA valve, A/C vacume elements, aspirator blower motor, bulbs, door switches, puddle lights, hood insulator, window switch, etc.) it is a sweet car and fits me just right. A little slow ( to be expected ) but better after the ALDA replacement. Now to the problem.
I have noticed that besides being noticeably more powerful with the A/C off, the tranny shifts like butter with the A/C off, but with it on, the shifts are hard. Any suggestions?

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Paul Levitt
1990 560SEL
1986 300 SDL
1988 300E
1992 400E (sold after 17yo crashed!)