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  #1  
Old 11-12-2000, 04:47 PM
magnolia
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Hi,
I have a 1982 300D with only 80,000 miles on it. The transmission shifts nicely through all gears except from 3rd to 4th--here it sort of revs (flares?) before it drops into gear. Someone told me it could be a vacuum modulator problem but my mechanic says that would only cause clunky shifting, not the other way round.

Please, please ya'll tell me it doesn't mean I am going to have to replace/rebuild the transmission because I really can't afford it!

Also, this problem seems to be worse when the car is cold.

Is there any kind of band-aid fix? Any replies will be appreciated.

Thank you ever so kindly.
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  #2  
Old 11-12-2000, 05:23 PM
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Join Date: Mar 2000
Location: Gainesville FL
Posts: 6,844
A bandage it is: shorten the control pressure cable by one turn (quicker shiffs) and tighten the modulator pressure one turn (clockwise)and get a different tech for your MB trans problems.

Modulator pressure is most important to shift pressure (how hard the shift is).

Unfortunately the 1981-82 transmissions had a number of areas that were modified in production by 1983-84. These included clutch pack end play, second gear band, and and 1st gear band servo piston (releases on application of 4th gear clutch pack and leaks caused reduced pressures).

The reason for these modifications were basically two related problems: #1 second gear hit too hard and #2 4th gear would flare, especially if one tried to get a decent second gear shift by modulator adjustment.

As it turns out the tranny will shift like that indefinely so if you can get your bandaid to work good enough just live with it til you are in a better position to fix it. Then get someone who knows what mods to do or it will still shift the same after its rebuilt, possibly.
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  #3  
Old 11-12-2000, 05:26 PM
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Join Date: Mar 2000
Location: Gainesville FL
Posts: 6,844
A band-aid it is: shorten the control pressure cable by one turn (quicker shiffs) and tighten the modulator pressure one turn (clockwise)and get a different tech for your MB trans problems.

Modulator pressure is most important to shift pressure (how hard the shift is).

Unfortunately the 1981-82 transmissions had a number of areas that were modified in production by 1983-84. These included clutch pack end play, second gear band, and and 1st gear band servo piston (releases on application of 4th gear clutch pack and leaks caused reduced pressures).

The reason for these modifications were basically two related problems: #1 second gear hit too hard and #2 4th gear would flare, especially if one tried to get a decent second gear shift by modulator adjustment.

As it turns out the tranny will shift like that indefinely, so if you can get your band-aid to work good enough just live with it til you are in a better position to fix it. Then get someone who knows what mods to do or it will still shift the same after its rebuilt, possibly.

------------------
Steve Brotherton
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician
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  #4  
Old 11-12-2000, 05:27 PM
magnolia
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Thank you, Steve. You're a king among men!
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  #5  
Old 11-12-2000, 07:39 PM
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Join Date: Sep 1999
Location: Cremona, Alta, Canada
Posts: 263
Steve;

I have the same problem with mine but I have tried the above mentioned fixes and it does not really change the 3-4 shift. So what I do is hold it in 3rd and shift manually at the same time I back off on the throttle. I was told that I have very little time left with this tranny but I have also been told it could last forever(almost). What do ya all think?
PS. I just changed oil in trans too.

------------------
Mark
82 300SD 100k
91 Caprice SS
92 Jetta TD
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  #6  
Old 11-12-2000, 11:58 PM
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Join Date: Jun 1999
Location: Quezon City, Philippines
Posts: 79
Magnolia, I had the same problem as yours a few months back. I checked the archives, read some of Steve's past postings, and followed his recommendations (adjust cable and increase pressure a bit).

Thanks to Steve, my car is now working fine.


------------------
Jake
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