This weekend, I will be attempting to fix my car's hard shifting (happens around 30 mph). I understand that it might be low vacuum in the modulator on the transmission. So i will attempt to look for the leak on the line.

Additionally, the fan only blows air to the windshield which suggests another vacuum leak.

Since both are vacuum controlled, are these two things related? I mean, will fixing the airflow control ALSO fix the transmission shifting or are they totally separate somehow?

The doorlocks work fine.

Any help is appreciated.

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Jennifer
90 350sdl

I'm not really familiar with the vacuum on that year of car, but in the 123's both problems would be caused by a vacuum leak. It's more likely that the leak is in the climate control than in the transmission system since there are more places the leak can occur in the climate control. If you plug the line that goes to the climate control and your shifting improves, you've probably narrowed down the problem to something in the climate control system.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

If the door locks work fine, it might be two separate issues, or more likely, its a leak in the climate control system that's making the car shift rough. Try plugging the CC system and see if the shifting smooths out...
Here's a good vacuum troubleshooting/repair guide:
http://www.schumanautomotive.com/forums/showthread.php?t=2755

EDIT
Hmm...someone beat me to it

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1985 300TD-euro 352,000 mi
1974 240D (1?)52,000 mi - has a new home now

[QUOTE= If you plug the line that goes to the climate control and your shifting improves, you've probably narrowed down the problem to something in the climate control system.[/QUOTE]

That sounds completely logical. Since the car has no A/C, I'd be willing to go with out the climate control anyway.

Is there anyone out there familiar enough with this car's vacuum system to tell me which line to plug?

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Jennifer
90 350sdl

Well, you may be currently reading my above post and looking at the troubleshooting guide
But to give you a quick answer, its the green vacuum line coming off the main line by the brake booster. Its kind of in a mess of other lines.

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1985 300TD-euro 352,000 mi
1974 240D (1?)52,000 mi - has a new home now

Yes it could be a vacuum leak or just a vacuum hose that was knocked off. I had the same problem recently after changing a glow plug. Have you been under the hood recently?

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1987 300TD 309, xxx 2.8.2014 10,000 mile OCI


Be careful of the toes you step on today, as they may be connected to the ass you have to kiss tomorrow. anonymous

“Be who you are and say what you feel, because those who mind don’t matter, and those who matter won’t mind.” Dr. Seuss

Women who work on their own cars just impress the hell out of me.

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OBK #55

1998 Lincoln Continental - Sold
Max 1984 300TD 285,000 miles - Sold
The Dee8gonator 1987 560SEC 196,000 miles - Sold
Orgasmatron - 2006 CLS500 90,000 miles
2002 C320 Wagon 122,000 miles
2016 AMG GTS 12,000 miles

Me too, especially ones that drive cars with broken A/Cs.

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80 300SD (129k mi) 82 240D stick (193k mi)77 240D auto - stick to be (153k mi) 85 380SL (145k mi) 89 BMW 535i 82 Diesel Rabbit Pickup (374k mi) 91 Jetta IDI Diesel (155k mi) 81 VW Rabbit Convertible Diesel 70 Triumph Spitfire Mk III (63kmi)66 Triumph TR4a IRS (90k mi)67 Ford F-100 (??)

i bet you like that 'sweaty' look too. it only gets hot when you are stopped in traffic anyway so i time my driving to avoid traffic jams.

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Jennifer
90 350sdl

nothing wrong with that. At least you have your priorities in order.

I might suggest plugging off the vacuum locks as well temporarily (yellow lines) if your "new" car has them....

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80 300SD (129k mi) 82 240D stick (193k mi)77 240D auto - stick to be (153k mi) 85 380SL (145k mi) 89 BMW 535i 82 Diesel Rabbit Pickup (374k mi) 91 Jetta IDI Diesel (155k mi) 81 VW Rabbit Convertible Diesel 70 Triumph Spitfire Mk III (63kmi)66 Triumph TR4a IRS (90k mi)67 Ford F-100 (??)

Don't worry about the locking system, it is run by a pump in the trunk spare-tire well. Totally separate from the climate control and shifting.

__________________

Gone to the dark side

- Jeff

Thanks! There is a remarkable improvement but it still shifts hard occasionally.

Since this is my first automatic car I am not sure how much shifting 'jerk' is normal.

One question...when you said plug the green tube- i did not see a solid green tube. i saw a gray one with a green stripe. please correct me if i am wrong. i want to plug the climate control line.

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Jennifer
90 350sdl

When adjusted properly, it is a silky-smooth shift at light throttle, under full-throttle it is solid, but no thump/jerk.

__________________

Gone to the dark side

- Jeff