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  #1  
Old 06-23-2014, 03:23 PM
zibsBenz
 
Join Date: Aug 2006
Location: Brantford On,Canada
Posts: 46
Transmission shifts

94 s320 with 492,000Km. Trans has never been serviced, car was a gift with 190,000 Km at the time. Its never winter driven. Last year there were a couple of OD shifting instances but they seemeed to have disappeared, we never experienced any more issues. This year the trans is having shifting issues.
At start up cold or hot it has no problems going into reverse or first instantly, no hesation at all. Start off in 1st, upshifts quickly and smooth, then next gear a slight lag and it shifts and so on, sometimes into overdrive but overdrive shift is becoming more rare.
As the trans gets warmer the lag between 2nd and 3rd is about 20 sec's and into the next gear most times will not shift unless speed is increased and engine revs are at about 4000 plus Rpm and you let off the accelerator slightly at which time it will shift instantly or not for about 60sec's or so.
There is no problem in down shifts, when slowing down or stopping it finds its lower range.
When driving in overdrive which at times it does get, although more rare, you never know when it will downshift out of OD. It will bounce up and down, downshift and upshift never staying.
Today I checked the fluid level cold before startup and it showed far up above 80 deg mark. After startup it dropped to nearly nothing on the dipstick, I checked it several times, so I presummed it was low. I got a Litre of Dexron111 and put it in, checked the fluid and now its way above the 80 degree pt. farther than when cold check. I'm now it seams 1ltr plus overfull I don't understand this. Went for a drive and nothing different in shifting , fluid level way overfull.
Any thoughts.
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  #2  
Old 06-23-2014, 05:27 PM
Registered User
 
Join Date: May 2012
Location: El Dorado Hills, CA, USA
Posts: 418
It can be torque converter drain back, or the radiator cooler has failed and the fluid is contaminated with coolant.
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  #3  
Old 06-23-2014, 05:35 PM
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Join Date: Feb 2011
Location: Modesto CA
Posts: 2,702
zB:

With all respect, yellow brick road or no, not even the Wizard could hope to go almost 300K miles without servicing and expect perfect performance!!!

Take the car to a competent facility, have the trans drained, filter changed, etc., and hope for the best.
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  #4  
Old 06-23-2014, 07:58 PM
zibsBenz
 
Join Date: Aug 2006
Location: Brantford On,Canada
Posts: 46
MAVA

Surprisingly the fluid looks clean on the dipstick. I did siphon some out using a clear hose down the tube and the fluid does not look dark or smell burnt or indication of coolant contamination. I wish trans fluid in my SRX with 80,000Km looked as clean and clear.
Torque converter drain back I don't know anything about, yet.

Frank
I understand what your saying but I've read too many horror stories of MB clients with working trans going in for service and shortly after have problems with their trans. When I did inquire about trans service at the dealers and an independant trans shop each commented the same, (if its working leave it alone as long as fluid is clean and up what do you want), but they would do it if I wanted it done.
I've had several North American cars and driven 400,000 plus Km and never serviced a trans but to always check to make sure ATF level was were it should be and looked clean, never had a problem, maybe I'm lucky.

I'm just looking for some input about the trans issue so when I do go to have it serviced I'm not going in blind and maybe its something I can DIY.
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  #5  
Old 06-23-2014, 09:53 PM
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Join Date: May 2012
Location: El Dorado Hills, CA, USA
Posts: 418
Zibs,

You may have so much play on the input shaft that great amounts of fluid flow back into the pan from the torque converter. All transmissions have this, but only rise a fraction in the pan.

The seals are just getting hard, and the clutch packs cannot pressurize as it gets warm or hot, so the transmissions shifts delay to the point where they will slip. Consequently, All of this is a clear indication for a rebuild .

Martin
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  #6  
Old 06-24-2014, 12:58 AM
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Join Date: May 2009
Posts: 274
Quote:
Originally Posted by zibsBenz View Post
MAVA

Surprisingly the fluid looks clean on the dipstick. I did siphon some out using a clear hose down the tube and the fluid does not look dark or smell burnt or indication of coolant contamination. I wish trans fluid in my SRX with 80,000Km looked as clean and clear.
Torque converter drain back I don't know anything about, yet.

Frank
I understand what your saying but I've read too many horror stories of MB clients with working trans going in for service and shortly after have problems with their trans. When I did inquire about trans service at the dealers and an independant trans shop each commented the same, (if its working leave it alone as long as fluid is clean and up what do you want), but they would do it if I wanted it done.
I've had several North American cars and driven 400,000 plus Km and never serviced a trans but to always check to make sure ATF level was were it should be and looked clean, never had a problem, maybe I'm lucky.

I'm just looking for some input about the trans issue so when I do go to have it serviced I'm not going in blind and maybe its something I can DIY.
When they do the fluid change, do make sure that the torque converter is drained too. Many garages fail to do this with the result that only about half the fluid is changed. Also, ensure that genuine MB filters and gaskets are used.

RayH
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