Transmission replacement necessary?

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Guy_Noir - 30 Oct 2004 19:50 GMT

A local mercedes repair shop has told me that I need a new transmission for
my 79' 300d. My vacuum pump had been broken for a coulpe of months before
the transmission went out, and I have been told by another 79' mercedes
owner that my tranny prob. might be related to my vacuum system & that I
might not need a new tranny. So my question is; Other than repairing the
vacuum pump, what other things should I check before deciding on a
replacement tranny? I have another mech. that is willing to help me
troubleshoot. Thanks in advance. -Jared in SoCal

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T.G. Lambach - 31 Oct 2004 00:52 GMT

How can you drive the car without (vacuum powered) brakes?

Vacuum pumps do break; they can be rebuilt with a repair kit.

Vacuum modulates the harshness of the transmission's shifts:
no vacuum = harsh shifts, full vacuum = soft shifts.

You don't state what exactly is actually wrong with the transmission so
advising anything about it is not possible.

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Wan-ning Tan - 31 Oct 2004 05:39 GMT

Exactly. And you raise the hood every time to shut off the engine
(manually), for several months? Wow, you are courageous!

Get the vacuum pump rebuilt/replaced first before driving that car
again! I am serious. You may hurt others or yourself.

By the way, there may be other damages depending on how the pump breaks.
1. Engine oil may be pushed through the vacuum hose and destroy other
vacuum elements;
2. Broken part from the pump can fall back into the timing chain case.
If it is big and hard enough, the chain may jump and guess what?

> How can you drive the car without (vacuum powered) brakes?
>
[quoted text clipped - 5 lines]
> You don't state what exactly is actually wrong with the transmission so
> advising anything about it is not possible.

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