[W126 Coupe] Re: Hard shift cause and cure

[Vance Rowley]

I haven't been following this thread closely, so forgive me if I am repeating something already mentioned.
I had a problem with the transmission on my Euro 560 some years back. If I did a 1st gear start or kickdown to 1st, it would not shift back into 2nd under acceleration and would over rev and cut the engine with the over rev circuit, then drop into 2nd (and no it wasn't the slider adjustment just behind the air filter to adjust the shift points). I had the car at the local MB service centre and they stripped it down, cleaned, tested, adjusted, etc, etc. The result was exactly the same. Basically they couldn't find the problem. At the time the fluid was fine and not milky or anything. I had at home this package of engine and transmission additive which I think a family member bought for me, but I never bothered with it (until then). I thought why not, it can't make things any worse, so I dumped in the bottle of the transmission additive in the tranny. Next few days driving, suddenly the transmission started working perfectly and has done ever since, but now the fluid looks milky, cloudy and sometimes foamy too, but the transmission itself works 100% and with great shift changes throughout the range.

So, after all that, it could be that sometime in the past (unless you have had the fluid changed) that a previous owner has done the same thing as I did and put some additive into the transmission. If so, I doubt that your transmission fluid is causing your shifting problem. Have you tried adjusting the modulator? Also, have you checked that your shift points are correct? i.e..under full acceleration shifting just before, or dead on the red line at 6000rpm and of course your limit marks per gear are also marked on your speedo.

Just a thought.
Vance.

----- Original Message ----- 
From: "Richard Hesek" <Richard_Hesek at raytheon.com>
To: <mbcoupes at mbcoupes.com>
Sent: Sunday, March 12, 2006 12:51 PM
Subject: [W126 Coupe] Re: Hard shift cause and cure


> .... However, the fluid was quite cloudy or foamy.
> Coolant in the transmission fluid.
> Time for a new radiator....
> 
> Check the fluid level with the trans at operation temp. (it will register
> 10mm lower when cold)
> I believe I read somewhere, that if the fluid level is too high the trans
> will churn up the fluid (like a blender) and cause it to be foamy..
> 
> Chet
> ======================
> 
> Good point Chet. I am aware that too much fluid can be bad also so I am in
> the habit if checking it.
>  The level is never too high. I feel it is easier to add than to remove
> fluid. I like to keep it above the half way point. If it got below that I
> would add it.
> The puzzling thing is, if their is a coolant leak into the trans fluid,
> then the trans fluid level would raise. This increase was not detectable.
> Must be a tiny leak.
> 
> Thanks,
> Rick Hesek