Question about 1991 Mercedes-Benz 420

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Car starts out in drive ok but will not shift. Its an automatic transmission and when you start out the engine changes but just reves up and will not shift down. I changed the oil and filter but it still will not shift.

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U have some sort of internal fluid leak from a defective seal, at this point u will need to have the trans pan removed to check for problem in valve body, but most likely the trans will require an overhaul.

Posted on Apr 22, 2009


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1997 toyota coroola dx automatic 214Kmiles. Gears not shifting correctly until car warms up.

Is this an automatic or manual transmission? When was the last time you changed the filter if it's an automatic? You may have a valve body problem too.

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Why does my Engine reves up when I shift?

Is the check engine light on?
does it do it when its cold, warm or all the time?
start by getting the transmission fluid and filter changed/check for debris but ussually this is the first sign you'll need a transmission rebuilt/replaced. But keep in mind I havent seen the vehicle

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Reving up when in gear driving

check your trans fluid, if its been a while flush it and change the filter if its reving and your speed doesnt change (slipping) if your speed changes check the TPS and speed sensors on the trans as well when you change fluid.

Jun 27, 2014 | 2004 Jeep Grand Cherokee

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Transmission sluggish, never used to be

the two events are most likely not realted.

Your description lacks the details of whether the engine is reving up, or not.

Transmission may not be generating pressure during the condition that you describe... Have to hook up pressure gauge to know what is happening.

if you are not making trans fluid pressure, you are certainly damaging by continuing to drive the unit.

Have you replaced the filter at the correct intervals?

Sep 18, 2009 | 2001 Chevrolet Impala

1 Answer

2003 Started reving high in 2nd when trying to shift to 3rd gear. Its an automatic transmission. No problems before this. No Slipping, No Hard Shifting.

Check the fluid while the engine is on in park..
If fluid is not low - it could be a vacume or modulator issue.. (the modular tells the trani when to shift via vacume presure)
Some shops give free estimates.

Jul 08, 2009 | 2003 GMC Sierra 1500

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2001 kia sportage 2WD automatic transmission problems

There only one problem wrong.You dont let your transmission warm up.You transmission has you warm up just like the motor.Try this and i promise when you take off it will shift like no other

Mar 09, 2009 | 2001 Kia Sportage

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Feels like transmission is slipping when changing gears.

Your TCU (Transmission Control Unit) is bad it will have a burnt diode inside it. You can find it behind the kick panel on the passenger side. i found them on ebay for about 79.00 with exchange.


Feb 02, 2009 | 2000 Honda Accord

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