Horror Story: My 300SD is Falling Apart...

[regsatx]

I've had it only since September 30. It was love at first sight, silver with remarkably preserved grey leather for an '85 SD with 224k on the clock. She handled great and ran superbly, at first. I drove her home 120 miles from where I bought her and she ruled the road, gliding almost effortlessly at 75mph while giving a cloud-like ride. Within a week, the honeymoon was over.
I posted an inquiry on this forum about vibration recently. I adjusted the idle, bringing it up to about 850-900rpm from 750rpm. It was OK for a day or so. Now the vibration has returned and something more ominous has surfaced. The transmission slipped a couple of times this morning. Then, on a subsequent trip, it would'nt upshift in Drive. I had to drop it into 3rd to make my brief, low-speed trip. Could a transmission go out that quickly? Did my adjusting the idle screw on the injection pump have caused this?
Guess I'll have to take to a shop to find out. I appreciate any suggestions...

Disappointed with my diesel

[Hatterasguy]

Thats nothing, it is a 20 year old car you are going to have problems. Did you change the engine mounts? Does the engine sound different whe it vibrates?

When was the trans fluid last changed or was it ever? Is it burnt or still nice and red? I would try some trans X first before it is rebuilt.

It sounds like you need to find a good shop that has knows MB diesels.

[tomm9298]

Have you checked fluid level? What color is the tranny fluid? Does the engine always shake at all speeds? Maybe some trash entered the fuel system, replace fuel filters first. The list for engine shaking goes on forever.... mounts, rack dampner, you name. Start simple and cheap and work on from there.

[TwitchKitty]

Don't drive a car with a malfunctioning automatic transmission. You can ride cheaper in a limo.

[whunter]

Hello regsatx
Relax, deep breathing.
OK, now, one step at a time.
#1. Check the transmission fluid level, engine running in park.
#2. Check all vacuum lines in engine compartment.

Ignore the vibration for the moment, FOCUS on the transmission.
With a little good fortune, you will find a vacuum leak and fix both problems.

Adjusting the idle screw on the injection pump could NOT have caused this.

Do not take to a shop to find out, it will waste money.

Do not make decisions when you are tired, hungry or angry...

[BrierS]

and keep us posted with what you find . . .

My recent purchase also has a vibration, rough running/shaking engine, hard shifting trans and I am working through trying to solve the problem(s). A shop will be a last resort since I view these fine vehicles as an educational hobby.

[JerryBro]

May not be as bad as it seems.

1. Remove and inspect the idle stop governor from the IP. It a spring loaded damper that smoths out the idle. Sometimes, when they wear, and the engine heats up, the vibration makes you think the motor is trying to jump out. If that looks ok, go for motor mounts and shock.
2. The tranny upshifts by looking at vacuum coming from the vacuum pump , and throttle position, as well as governor speed. If the lines to the Alda get clogged it can throw the whole relationship out. Clean out the lines going to and from the Alda and check the adjustment of the Bowden cable.

I had the same problems on my 84 when I bought it a couple years ago, following these steps solved it.

Jerry