Hi everyone,


For the past two months (1800 miles to be exact), I have been the owner of a ’85 300D turbo, with 223k miles on the clock. The car has climate control (with the horizontal line of black switches and vertical temperature control), cruise control I have yet to sample, and occasional issues with engine shutoff (these only occur after the engine is started and stopped in series in a quick succession).

There is no AC, the climate control is shot, and the central locking does not work (all the door locks go down except the front passenger-side). These last issues suggest vacuum leaks, but none has been troubling enough to budget repair time or cash.

I live in Northern California, where it’s warm this time of year during the day (High 60s), and considerably colder at night (35-50 degrees, usually). With a strong-working w123 sunroof, you really don’t need air conditioning.

However, one problem has been bothering me:

I’ve noticed that when the car is first started up, the first-to-second upshift is rather harsh. The shift is late, and the car sort of jerks forward. This occurs irrespective if I load on the gas very lightly, or punch it. A smooth shift occurs, occasionally, if the gas pedal is somewhere in the middle (and even then I’m wondering if it isn’t some other factor working here)

All the other upshifts (2-3, 3-4) are silky smooth. ALL of the downshifts are smooth. Once the car warms up (i.e. drive for 10+ minutes) the 1-to-2 shift problem seems to go away. But after prolonged driving in traffic, it can come back.

Also, this problem is more prevalent at night than during the daytime. I took the car out for an Italian tune-up (joyride?) on the I-280 one night, but after a couple of long, slow stop lights on the way home, the 1-to-2 shift was harsh again.

What should I do to address the transmission problem? Is it a result of my car’s clearly troubled vacuum systems (leaks, etc.), or is it merely in need of an adjustment or fluid change?

Thank you for your wisdom,

NH

Probably a vacuum problem. The transmission has a vacuum operated modulator valve that helps smooth out shifts. Most likely either the valve is shot or the vacuum it's getting is irregular. There are loads of threads on this so if you spend a little time doing searches you'll find all sorts of info. One thing though, you'll almost certainly need a MityVac to get anywhere with this. If money is an issue buy one of the cheaper plastic ones (you can find them at Kragen or Autozone, or online), just don't drop it on the driveway. With the info you can search on this Forum, a little patience and your MityVac you should be able to fix your locks, transmission and shutoff problems without spending much money.

__________________
LRG
1987 300D Turbo 175K
2006 Toyota Prius, efficent but no soul
1985 300 TDT(130K miles of trouble free motoring)now sold