Check your flex disk (between tranny and driveshaft) for cracks or obvious wear. If it is clunking there, you will see where the driveshaft has been working on the rubber. This will cause thumps on downshifts.

The MitiVac is very easy to use -- squeeze handle and release, and it sucks air in. Has a gauge on it so you can see what, if any, vac you are producing. Purely mechanical and hand operated.

There isn't really a repair kit, except for the engine driven vac pump, and I'd not tear into that unless you know for sure it's dead. Usually isn't on the later ones.

The things to check are the rubber connectors on the hard plastic lines -- some are straight, some are T or Y shaped -- those I would get from a dealer, the straight bits can be replaced with vac line from any autoparts store. Go the the better ones, though -- some of the low cost places like AutoZone have cheap vac line that fails pretty fast.

To use your MitiVac to test things, unplug the line you want to check from the main supply or servo, insert the correct adapeter from the assortment with the pump into the pump hose, and stick the connector into the line you want to check. The very small taperd tip works best for me. Operate pump and see if a) the system holds vac and b) does it operate. The AC and doorlock systems have vac reservoirs, so it will take many squeezes of the pump to pull a vac on them. If you pump and there never is any vac, you have a leak somewhere and need to start checking connection.

The tranny setup is different for differenct models. I think the turbo modles are similar to my W124 DT, so here goes. There is a valve, either on the valve cover or on the IP itself, connected to the throttle linkage. There will be a white vac line connected to it from the main hose that goes to the brake booster. From the valve there will be a line that goes to the blue vac amplifier on the fender somewhere. There are several hoses connected here, including one that is labeled "trans" -- also one labeled "vac". Check all the rubber ends, replace an that are hard and slide off the plastic parts too easily, or soft and sticky. Pull the line marked "trans" with the engine running at idle and connect the MitiVac there. You should have 15" or more of vac. If you then slightly open the throttle, the vac must drop to about 12", then progressively drop to 0 so the throttle is opened fully. You shouldn't open the throttle with the car in park and engine running, so you can only check to see that it changes.

If the vac isn't that high, you have a leak. If it is OK, connect the MitiVac to the tranny line you unplugged and make sure it holds vac. If not, and the hoses are connectors on the modulator (on the tranny) are ok, the modulator is bad.

Hope this helps!

There are several posts of vac diagrams on the site -- search for "vacuum diagram" and see if you find what you need.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!