I spent a couple happy hours last night reading this monster post "It's CRITICAL... how you set your transmission's vacuum system on your diesel MBZ..." It's CRITICAL... how you set your transmission's vacuum system on your diesel MBZ... - PeachParts Mercedes ShopForum because my '81 300TD 1. had a vacuum leak and 2. shifted HARD. After about page 28, the thread getting hard to follow, so I am starting a new post to focus on my personal issues.

Before it tried to take its own life and had to get an engine transplant, it had developed a vacuum leak. Using a Mityvac, I had traced at least one leak to the EGR black box components. Now that it is running again, I want to get the shifting sorted.

This morning I disconnected the lines going to the Central Plug (number 71 on the beautiful simple functional diagram I got off of PeterSchmid.com. Now the thing shifts like buttah. Amazing difference.

We're not there yet though. Now with moderate throttle 1-2 is almost undetectable, but 2-3 flares, 3-4 is is fine. Under hard acceleration from a stop (like when doing an Italian tune up) it flares at each shift.

I'm thinking I should check the vacuum on the VCV and tune it to 8" and 0". Does that sound like the next step?

__________________
Mike

1980 300SD
1981 300TD
1998 E320 Gasser Wagon
2000 SL500

Yes

However, there is no magic in the range of 8-10". I have the SD set at 8" and it is a perfect compromise for me and the condition of this trans. Yours might perform perfectly fine at 11" with crisp shifts and no flares. Going lower will cause the trans to start to bang on downshifts.

Or, you might need 6" to achieve the same result.

Adjust and make the test drives to confirm.

Be very careful on the adjustment of the VCV. 5 degrees of screw rotation makes a big difference. Keep the Mityvac pumped up and watch it carefully during the adjustment. Hopefully the cap on the modulator doesn't leak too badly.