My 300D 2.5 1991 has been shifting hard, after making some checks, vac pump is fine pulling down to 119mmHg, and runing the engine hooking up the test gauges, i could only get the required vac to the transmission when i plug the line going to the left side of the engine where the turbo boost is and the various acumulators. does any one have a fool proof way to narrow it down beyond that? I do not know what that side of the engine should be pulling normally. and disconnecting and plugging the lines is not going to helpful if i do not find anything major. Any help would be appreciated, have access to a motorized vac pump to run tests.