Hi guys, I've inherited a 1981 300SD (252,000 miles, yes I'm applying for a mileage badge) from Grandma and have spent the last couple of weeks going blind from reading through the forums here and elsewhere, then working on getting the car in shape. Here's the question. When I got the car the 1-2 shift was brutal, as in barking the tires every time. After straightening out, and sealing up all the vacuum lines and checking that the modulator is getting good vacuum, (which was zero before, now about 7in) but not touching any adjustments, it still bites pretty hard going from first to second but almost flares a little going into the higher gears. I'm pretty well versed now on the possible adjustments, so any suggestions? My local indy mechanic says "that's how they are supposed to shift", which can't be right. Short of spending more than the value of the car I want it all working right.

Yeah- when something's amiss. I hate it when people give you that crap. Loosely translated it means 'I'm ignorant and don't know dick and way too lazy to try and find out, but I'll still do my part to lead you down the primrose path and pontificate about how these cars are supposed to run'. Mercedes' are not supposed to be harsh or abrupt ever, which is a given considering that they used to be the most well made automobiles in the world.
Wish I could help, my car does the same thing- I'm hoping it's just a transmission service issue- no modulators or adjustments. Hard 1-2 shifts are a common problem I believe.

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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)

With a worn(but not worn out) tranny, I believe it to be a balancing act between enough vacuum to keep you from spilling your coffee every shift and getting sideways in the rain, and not flairing/draggy shifting. No two car's seem to be the same after a quarter million miles.

The earlier trans had a harsher 1/2 than the later's as a matter of course, there are updated internals available. Mercedes made a bunch of running changes to this tranny as they knew darn well it was not up to snuff in several ways. They eventually got pretty good at it, I drove an 85 SD awhile back that was just wonderful, and it had an ungodly number of miles on the trans.

If it's any consolation, my 1/2 and 2/3 can be made pretty good, but at that vac setting my 3/4 will not flare, but engage really slowly. If I set the 3/4 to not slip(which is a window of about 2 inches of vacuum), the 1/2 and 2/3 will be killers. Gotta love it...


I'd do something really, really bad if I could just stick a 700R4 in this thing..

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One more Radar Lover gone...
1982 VW Caddy diesel 406K 1.9L AAZ
1994 E320 195K

Since I got the vacuum tuned up as best I can, I might have to change the fluid and filter and just live with it awhile. I've got the 722.303 transmission I think, and I hear they came out with an improved band for it. Not a project I'm up to right now. Too busy getting A/C compressors to last more than two days. Here in PHX it's a necessity to have the a/c working, and I've had a new compressor installed, new receiver-drier, the system vacuumed, cleaned, vacuumed again, and charged twice! (including two new compressors!!). After about 2 days the compressor starts clattering and clanging like I threw 2 rods through the engine! It still cools well, but at an idle it sounds so bad people look at me scared when I park next to them! On a brighter note, this forum has been outstanding in helping me diagnose and solve the rest of my problems, thanks people!

I thought I was also doomed to very harsh shifting, especially 1 & 2 on a 1985 300D with 126,000 miles that I just recently purchased. Took it two a local independent garage that specializes in transmissions, and now it shifts much, much better. They changed the fluid, filter, repaced the modulator (only $30.00) and played with the vacuum settings. Total bill was only $170.00. I was amazed at the improvement. Keep trying, you can fix your problem if you find the right tranny guy.

I might ad that I gave the mechanic several printouts of threads from this forum addressing this issue. While he said he really didn't need them, they were covered with grease prints when I picked up the vehicle.

I would replace the transmission fluid and the filter. I'm sure that would help things out a some.

-George

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'81 300TD (White) 225,000 miles
'85 300SD (Burgandy) 239,000 miles
'86 300SDL (Silver) 340,000 miles

Setting the pressure at the modulator will often stop the upshift flares.

Thanks for the encouragement, I'm getting it dialed in now, and it is slowly getting better. Now for all the rest of the little bugs.....

300Dguy: What is the name of the transmission shop you had such ggod luck with? I am in upstate NY and would make the drive to have a quality shop work on my 83 300SD transmission.

Thanks.

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1983 300SD -- 220k
1983 240D euro -- 225k - sold
2002 VW Passat W8 - Fast
1985 BMW 528e -- 356k - sold
1996 BMW 328Ic - crumpled into bits

Mine does that too, figured it was the way high, high side pressure running r134. PO said it started after the conversion.

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One more Radar Lover gone...
1982 VW Caddy diesel 406K 1.9L AAZ
1994 E320 195K