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  #1  
Old 03-20-2013, 02:35 PM
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76 300D Transmission shift issues

Can anyone tell me if the transmission in my 76 300d can be adjusted. It delays in all gears. When the car warms up it shifts like it is supposed to however I noticed when driving on the expressway it starts hunting gears at around 55-65mph. Is there any kind of adjustment that can be done? Car used to be in pristine condition until my dad let it sit for a number of years. I want to be able to drive it may 2-3 times a week to get out of my acura mdx.
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  #2  
Old 03-20-2013, 03:29 PM
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jc:

First things first; you may or not be aware that the transmission is actually a four-speed trans (722.1xx)(W4B025) that normally starts in 2nd gear, although a full throttle start w/kickdown will force a 1st gear start.

The shifting delay when cold, and the 4-3-4 hunting at 55-65 mph suggest a problem with the governor (sticking), or a leakage of governor pressure.
This comment does assume that the fluid level is correct. Since the car has been out of service for a while, a change of fluid and filter would be in order as a first step.

Other possibilities include intermittent activation of the kickdown switch, and mis-adjustment of the throttle pressure linkage to the trans.
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  #3  
Old 03-21-2013, 02:40 AM
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Assuming you have have clean fluid and the correct amount, clean filters etc and a 722.118 with the throttle connection (rather than vacuum only) - I'd start by checking the throttle bushings.

And to answer the question - yes it can be adjusted. If you have the transmission I think you have there is adjustment at the throttle linkage and at the back of the transmission where you can change the modulating pressure. Start with the throttle though. To adjust the modulating pressure you need gauges.
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  #4  
Old 03-24-2013, 12:56 PM
Pooka
 
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I had this take place on a 1975 230 (gas) and a 1978 240D. Both times it was a bad vacuum modulator.

These are cheap and easy to replace. Then they are very, very difficult to adjust and like Stretch said you will need a set of gauges.

You might just want to take it to a shop that deals with Mercedes transmissions. It could be the cheapest route in the long run.
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Old 03-24-2013, 03:39 PM
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[QUOTE=Pooka;3119353]I had this take place on a 1975 230 (gas) and a 1978 240D. Both times it was a bad vacuum modulator.

jc:

Re: The above quote from Pooka
Both of those transmissions are equipped with vacuum modulators.

The trans in the 76 300D is not; There is a fixed pressure plug installed where there would otherwise be a vacuum modulator.
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  #6  
Old 03-24-2013, 04:48 PM
Pooka
 
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I was wondering about that. I figured if I just posted my experience with the VM someone would offer more info on it.

Thanks for the correction.
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