[W126 Coupe] lazy transmission

[Iain Gunn]

Vance, until the fluid and filter is changed, your really have no starting point. It's like trying to diagnose a cold engine. As far as draining the converter, most standard shops don't do it, because they figure there is not much in it anyway, so its not worth the time. I drained mine, no big deal. What's more important is that when you drain the pan, you remove all the bolts except one in the corner slowly. This drains the transmission pan slowly, so when you finally remove the last bolt, you have not washed all the sediment out of the pan, because you want to observe what is in there. If its got large pieces of aluminum or steel in there, 1/16" and larger, you may be in trouble.
If its just, small bits of brass and dust, that's normal, that's what the clutch plates are made of.
Good Luck, Iain
  ----- Original Message ----- 
  From: Vance Rowley 
  To: mbcoupes at mbcoupes.com 
  Sent: Saturday, December 19, 2009 7:26 AM
  Subject: Re: [W126 Coupe] lazy transmission


  Hi Markus,
   I am probably due for a change and intend to get it done, although there is no burn smell from the existing fluid.
  Is there a particular brand of synthetic that you would recommend? 
  I have been putting this off for quite a long time now. Main reason being, after the last time I had it done, I finished up with shift problems worse than I have now. To cut a long story short, after several visits back to my local MB service centre (with no results) I gave up. Then one day while searching for something around the house, I came across a bottle of Transmission Reconditioner which I forgot I had as part of a package I bought sometime in the past. I thought (can't do any harm) and dumped it in. About a week later, the transmission suddenly started working perfectly, and has done until recently.
  You can probably see my way of thinking and reluctance to getting a fluid and filter change, as this would mean the Transmission Reconditioner I put in (which I forgot the brand) would also be drained off. Although I discovered the last time I had it done, the torque converter was drained also, which I believe is the correct procedure. (could this have been the cause of the original problem?) I believe there is a hot debate going on whether or not to have the TC drained.
  So, should I go ahead and have a complete fluid and filter change with TC drain, or just try the fluid and filter without bothering with the TC? Your thoughts (and anyone else's) are greatly appreciated.
   
  Cheers,
  Vance. 

------------------------------------------------------------------------------
  Date: Fri, 18 Dec 2009 11:27:51 -0500
  From: markusfmeyer at gmail.com
  To: vance.rowley at thestart.eu; mbcoupes at mbcoupes.com
  Subject: Re: [W126 Coupe] lazy transmission


  When is the last time you changed your trans oil and filter?  If more than 25-30K miles ago, its time.  I found when I switched all my vehicles over to synthetic they responded quite well and shifted better, your experience may vary.

  Markus


  2009/12/18 Vance Rowley <vance_rowley at hotmail.com>

    Not heard from anyone in a while. Had problems with my email, so changed it.
    Anyway, getting back to the subject, I have recently been having what I would call lazy shifting with the transmission. There is no slipping and seems fine on starting off as normal (in 2nd as it does) and also seems fine by flooring it to get 1st and then back to 2nd. But then (under normal acceleration) it can't seem to make up it's mind when to shift to 3rd, although this isn't as bad as it is from 3rd to 4th. Even after reaching a constant speed of say 30mph in 3rd (and the E/S switch set at E) most of the time it will just stay in 3rd and not drop into 4th. Sometimes it will, but most of the time I have to blip the throttle a little, then ease off for it to drop into 4th. Sometimes even this doesn't work. 
    Summary is all downshifts seem fine and upshift from 1st to 2nd is perfect. Upshift from 2nd to 3rd is OK most of the time, but upshift from 3rd to 4th depends on what mood it's in at the time.
    Should I just change my tranny fluid and filter, or is there some other explanation for this?
     
    Cheers,
    Vance
    91 560sec euro 


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