I just bought my 1980 300sd a couple of weeks ago. Since I bought it, it has had a hard shift. AS it shifts through the gears it gets progressivley harder. 1-2 is normal, 2-3 is sometimes normal and sometimes slightly hard, then 3-4 is very hard. It feels as though there was a bad mount because I could feel something moving hard with the clunk from 3-4 gear. I changed the passenger motor mount last night since it was visibly shot and thought to be the culprit of the hard shifting. Shifting seemed to get a little better but we still have a shift harder thatn the normal hard shift our cars have.

When I bought the vehicle I soon noticed that it lacked the vacuum module on the top back of the IP. I pulled one from my spare parts motor and attached all of the vacuum lines correctly. Still hard shifting. Maybe slightly better.

Along with the hard shifting there has been the no shutting off problem which would lead to a vacuum leak. Also, the doors don't lock and unlock automatically. The Climate control seems to work normally vacuum-wise. I have double checked all vacuum lines and connections under the hood and at the transmission and everything is visibly soild.

I now get around to assuring the transmission fluid is correctly filled. It seems to be 1/2 inch high when cold in park with the engine running. I am going to correct the fluis level tomorrow.

I am wondering where to start here. I dont want to tear apart all of the door panels if not neccessary. Will a leak at a door lock cause a hard shift and a no shut off? I am also thinking that there is a vacuum pod or something on the ignition that may be leaking. Would this cause the shut off and the hard shift?

I will buy a mityvac when possible but is there a direction I should head until then?

Thanks fellow mb diesel friends!!!!!

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1998 E320 150,000
1980 300SD 240,000
1965 190D 79,000

Dont bother playing with the trans, get the vac fixed first. The trans probs may just disappear. I have found that by just disconnecting different vac lines and plugging the vac side you can soon find when things start to work eg engine turn off. You can then work your way down that line & find the problem. Do your brakes work well, that is the booster? If they do then its not likely to be the the vac pump.

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Grumpy Old Diesel Owners Club group

I no longer question authority, I annoy authority. More effect, less effort....

1967 230-6 auto parts car. rust bucket.
1980 300D now parts car 800k miles
1984 300D 500k miles
1987 250td 160k miles English import
2001 jeep turbo diesel 130k miles
1998 jeep tdi ~ followed me home. Needs a turbo.
1968 Ford F750 truck. 6-354 diesel conversion.
Other toys ~J.D.,Cat & GM ~ mainly earth moving

Breaks seem to be working correctly. I have asn other vacuum pump off of my spare motor just in case.

So I a going to plug various vac side tubes like you have suggested. Do I just turn off the ignition then start plugging? While the car turn off then? Or do I have to start the car, plug, then shut off ignition over and over again? Also, Is there a chance of the door locks making the problem.

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1998 E320 150,000
1980 300SD 240,000
1965 190D 79,000

vac leaks just last week I found 4 servos that control heating flaps shot.Plugged lines shift good.Manually opened flaps and have warm feet.

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1999 w140, quit voting to old, and to old to fight, a god damned veteran

How do you tell if they are shot? Visibly shot? I have noticed that the climate control is working correctly, but I can get in there to check as I am going to be replacing my blower motor.

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1998 E320 150,000
1980 300SD 240,000
1965 190D 79,000

I had a leak on the climate control system and the door locks. I plugged both lines for now. The car now shuts off but kind of roughly. There must be another leak that I cannot find.

Also the hard shifting is still present. Could this be because the transmission is overfilled?

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1998 E320 150,000
1980 300SD 240,000
1965 190D 79,000