I'm looking at the Sun Valley Mercedes Dismantlers website, and they have vacuum diagrams for various Merz transmissions. Which designation do I have? '85 Federal 300D turbo. My trans is shifting a bit too hard and also clunking on the 3-4 and 4-3 shifts, so I suspect too little vacuum to the modulator, but hey what do I know. The vacuum system on this car really puts the zap on my head. Golly gee all those lines confuse me and I get epileptic seizures just from looking at them.
I was out late last night about 12 am goin' 'round the beltway in DC 'blowing' the car out. Since I will probably at the most get to put maybe 5k/year on the car if I get really busy, I want to make sure it gets some exercise whenever I can find the time. I exited at Wisconsin Ave, and went through Bethesda on my way back home. I usually use S for city driving but I had it in D at the time. I floored it going about 40 and hit the kickdown switch. It kicked down to first or second, dunno which one, RPMs went up immediately and I then realized I did not want to be in such a low gear and took my foot out of it and it immediately shifted to a higher gear. I remember thinking at the time that maybe it was not so good to do that sort of thing. I'm still getting used to this car. The 3-4 & 4-3 clunking was always present(at least since I acquired it 4 mths ago), but it seemed that after the stressful time I had given it, it was now more pronounced. Maybe it's just my imagination, I'll go for another drive tonight. 1-2, 2-3 shifts in S are crisp and lack the clunk. Whenever I am in D though, it seems as though all shifts exhibit the clunk, unless the thing is floored. 4-3 clunks as I am slowing down. Just had the diff oil changed 800 mi after I had changed it myself(Redline Shockproof, previously Valvoline Full Synth), as I had to have 2 new axles installed.
This is a most disconcerting noisy clunk. I know it's probably vacuum related, at least I hope. BTW the ignition cutoff is no longer instantaneous. It takes about a second or so. The door locks work, but don't have but 3 or 4 cycles before they run out of vacuum if the engine's off. Seems as though the center vents take a bit of time to start blowing also, after the other ones are at full output. After this episode, I checked trans fluid, about 1/4" above full mark when hot, no foam and transparent red- I checked it before(on my trip from GA to DC) when it was hot and it only registered at the full mark. I previously changed the filter and fluid with Valvoline Maxlife. Is that stuff OK?
I am truly sorry to keep bugging the forums for help with my problems, and I have read pages of threads I searched for already. I feel like I still need a specific answer to my dilemma. From my understanding I have a vacuum leak. But- did I overstress the trans and hurt something? I usually drive like grandma compared to everyone else, and every little thing- even just hitting a pothole- makes me lose sleep thinking about it. So this latest workout I gave the car has gotten me worried that I might have torn something up in there. thanks

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'02 BMW 325i
'85 300D 450k
'93 190E 2.6 170k(killed by tree)
'08 Ducati Hypermotard 1100S 6k
'06 Ducati S2R800 14k(sold)