Hello,

I have a '83 240D that I am about ready to sell. It's having a problem shifting down while going uphills or when the gas pedal is to the floor or almost to the floor and I am trying to accelerate fast. When I go uphills, or attempt to accelerate fast (not really "fast" when talking about a 240D), the car will upshift at certain speeds no matter how big the hill or how far the accelerator pedal is pushed down and it upshifts too quickly, so I have to manually shift to a lower gear. The car also continues to run for about two to three seconds after the ignition is off and the power door locks are hesitant to unlock after I unlock the driver's door lock. I was told that there are three vacuum controls, the ignition, the transmission, and the door locks. Is there any way I could find out what the problem is without spending $80/hour or higher for a mechanic to look at it? Thanks for the help.

Moved for better answer.

Your best bet is to invest in a MityVac if you don't have one. I got mine from Harbor Freght. Here is what I got.
Harbor Freight MityVac
It's the best investment I have made for my MB.

You may have two problems
1- Vacuum leaks causing slow doorlocks, not shutting off, etc...
Try Diesel Giants Vaccum Troubleshooting Guide and see if you can find a leak or two.

2- Bad kickdown switch causing downshifting problems.
Try disconnecting the kickdown switch under your go petal and see if that changes your down shifting problem. They tend to get gunked up being on the floor behind the petal and get stuck. If that solves the down shift problem you may need a new kickdown switch. Or maybe some cleaning might work I have not had to mess with mine but I have read a lot about them.

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Thanks for the help, I will check out that website!