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Hmm. My 220D sits in 2nd, but downshifts into first briefly as soon as I touch the accelerator. The 300TE I'm not sure, I've not checked since it runs fine. The 87 300D seems to start in 1st all the time, or has a torque converter lockup that engages at 40-45 mph. I'm not sure, haven't looked. If there isn't a lockup, I'm certain it starts in 1st, as it is geared really high (2200 rpm at 60 mph).
Shift timing and quality is also determined by a vacuum system -- MB seems to have used the same tranny on everything with minor changes, so to vacuum modulate the diesels came up with a vacuum system that takes vacuum from the main pump and adjusts it to feed load and throttle position to the vacuum modulator. There is a little metal or plastic box (the 87 is metal, on the IP) connected to the throttle linkage with a black, white, and on the 87, black with red stripe vacuum lines attatched. It is also connected to the manifold (via the black with red strip line). If these are leaking, you might not be getting good shifts, or if the valve has failed, or the modulator is out of adjustment.
Basically, MB transmissions shift pretty soft at light throttle -- my brother's 75 300D is kinda slidy, but that is because a bushing is missing on the kickdown rod.
The kickdown cable adjusts upshift speed more than it adjusts shift quality. Check your vaccum lines for leaking rubber ends -- the hard plastic is usually OK.
If you cannot get rid of the flare on 2-3, see if someone can adjust the bands (the 2nd gear band may be too loose). This is a real pain, as the adjustment bolt is a breakaway to prevent anyone adjusting it.....! This can also mean that the clutches are worn out, though, so you may need a rebuild, although I'd not really expect that.
I would go easy on the old girl, though -- really romping down on an automatic that is shifting sloppy can finish off the clutches really fast!
You can also play games with the tranny fluid -- a little Type F will cause it to shift more firmly (different friction modifiers, the clutches grab better) BUT if it has lots of miles on it changing fluid is chancy -- it can sometimes cause trouble! Don't replace the Mercon III with 100% Type F at any rate, it will shift VERY hard!
MB does not recommend this, so proceed with caution!
Peter
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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!
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