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  #1  
Old 06-09-2003, 02:10 PM
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Downshifting automatics?

Maybe this is a stupid question but is it okay to manually downshift the MB automatic? I find that often cruising along between 25-35mph when I need to accelerate, like after slowing down for someone to take a left, when I press on the accelerator it takes a while for boost to build and the car to start to move well again. This is because the rpms are around 1500-1600. I have found if I just drop it down to S, the rpms jump right up to 2100-2200 and away I go. Now I know I can just floor it and it will downshift but I don't quite need all that lurching, buzzing and reving to get where I need to get, just a few more revs to get me up and moving. So the question is, I am doing any damage by shifting it this way? RT
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  #2  
Old 06-09-2003, 02:44 PM
95*E300
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Great question!

I too have had the urge to downshift to increase the rpms when I find myself in the same situation. My 606 engine (non-turbo) seems to bog at under 2000 rpm and I don't like to floorboard the accelerator to achieve just a little pickup.

I have tried the downshift a couple of times (very successfully I might add and it felt like I was contributing to the driving process!!) but wondered if MB would frown on this (I can't see why) but in reading rwthomas1's question I echo it.
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Old 06-09-2003, 02:52 PM
Randall Kress
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When these cars were new, they were advertised by Mercedes-Benz as having an automatic that can be "shifted through the gates if the driver is so inclined" and used like a manual. Many Mercedes owners enjoy using their automatics like sticks, but just be careful not to over-rev the motor (very hard to do). The Mercedes automatic, you will find, is a lot more enjoyable than their manuals (despite what some board members will contest), Mercedes is known for its gated automatics.
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Old 06-09-2003, 02:59 PM
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P-R-N-D-S-L What does "s" mean on the auto tranmission?

Always curious about this, "What does "s" mean on the auto tranmission?"

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Old 06-09-2003, 03:09 PM
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  #6  
Old 06-09-2003, 03:11 PM
95*E300
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Ok

Maybe this explains the funny zig-zag pattern of the shifter track - as opposed to the American striaight pull or push of the shifter.

I am used to shifting having owned two Corvettes - the 96 with a ZF 6 speed - I got tired of shifting that one! But I would like to shift to maximize my diesel's torque curve. I will start trying this - you are saying Randall that we can start at the low end and shift every gear if we want to?

I realize that this appears to be a funny question but my gas 4.0L Jeeps don't require any help as they develop 82% of their torque at idle and really can move or downshift easily all by themselves. But the 3.0L 606 diesel does need some shift management from time to time. I have found that the DOHC does take a bit more winding up to achieve what the 4.0L gassers do at lower rpms. Perhaps it is just me learning to drive a Euro-cruiser! Thanks,
Mike
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  #7  
Old 06-09-2003, 03:24 PM
95*E300
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Shifter labeling

My shifter says:

P-R-N-D-3-2 so I can't start out in 1st it looks like. I assume that if I put it in 2 it will probably start in 1 and then go to 2 but wait on me to put it into 3rd. However - since I don't have overdrive (didn't list it in my book) why have the D and the 3 both on the shifter?
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  #8  
Old 06-09-2003, 03:33 PM
narwhal
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You may want to do a search on this. I seem to recall Gilly or Dr. Diesel or some other (what I would consider) authority saying this was ok. I regularly downshift and upshift my auto, but I don't take it anywhere redline.
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  #9  
Old 06-09-2003, 04:09 PM
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I'm reminded of the old story....

....about Fangio (he had an MB dealership in his native Argentina) taking a journalist around a race track in a new 500SEL. The journalist remarked that the ride was unusually smooth given the high speed they were circulating at, noting that Fangio seemed to use the shifter on the auto box quite a bit. Now, I believe 'jornalistic integrity' to be an oxymoron, but, then again, this appears to be an observation, not an opinion.

I have used the 4->3 shift technique for years to avoid the kickdown/noise alternative and would only suggest that you keep an eye on the little dots on the speedometer which indicate shift points. If you are anywhere near the ~70 mph (3 dots) mark, don't risk shifting down. While the rev limiter may catch things in time, why risk it?

Now, my tranny (300SD 1983, 196k) had an overhaul at 130k or so, but that was the result of several years of low speed driving, with many auto shifts, in the city. On the freeway I have used the 4->3 to get things moving for years, and no problems in the last 60k+ miles.
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  #10  
Old 06-09-2003, 04:28 PM
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narwhal - have some fun, rev it up! Looky here: Rev Limiter
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  #11  
Old 06-09-2003, 04:29 PM
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One other thing that I've found is that keeping the shifter in "S" during city driving (35mph or less) really helps. This keeps the engine in its power band, and thus makes it react more when the throttle's pushed down. I haven't noticed a real change in fuel mileage since I started driving the car this way...but IMHO it makes city driving more pleasant.
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  #12  
Old 06-09-2003, 07:17 PM
turbodiesel
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I do it all the time. When in slow traffic or cruising around town and want a little extra boost, I put it in 3rd. When I need power at 25-40mph I throw it in 1st as well.. I don't see a problem with it.
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  #13  
Old 06-09-2003, 09:39 PM
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Manual shifting an MB Auto

It works for gas 123's as well. My brother's 84 123 200 auto was almost as anaemic in power dilivery as a diesel. On a long trip of several thousand kilometers he discovered that by downshifting manually it made the car far more driveable and he used that technique ever since.

And I also agree with the poster who disliked MB manuals. Having owned both I will only look for a manual on a diesel because of more pep and better fuel economy, and less vacume related maintenance issues.

- Peter.
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  #14  
Old 06-09-2003, 10:16 PM
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When I go down a long hill I always shift from D to 4 just to slow a bit. After 180,000 miles {C280} my transmission works perfectly. Since these are sealed units and never require any service, I think MB has done there home work. Keep in mind MB's do not need much if any maintenace.
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  #15  
Old 06-09-2003, 10:25 PM
turbodiesel
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Sealed for life transmissions... what a scam, IMO.

An automatic transmission, nomatter how new, still gets hot under certian conditions, changing the properties of the ATF and releases clutch material into the fluid as clutch wear progresses. The fluid should still be changed every 30,000 miles. If you were to change your fluid now the transmission would be rendered useless.
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