Going from Park into Drive at OT delivers a very strong impact to my backside. This ony occurs when the engine is at operating temperature. The transmission shifts are perfect otherwise, somewhat firm, regardless of engine temperature. I am assuming that this is indicative of either a vacuum leak cold that softens the shift into gear or a vacuum leak at OT causing it to slam into gear. This slamming into gear began when I adjusted the vacuum control module on the side of the injection pump. The reason for this adjustment was to firm the shifts as I had a little flaring from 2-3. What I don't understand is the significant difference from cold to hot. Any thoughts?

O.B.,

The valve you want to adjust is on the Left/Driver's side of your TRANSMISSION!

It is covered with a small plastic cap , and has a "T" handle inset into the
compass.

Do a Search on tranny adjustment.

C.I.
Thanks for your response but I don't think you understood the situation. I do know about the three different adjustments that can be made to the shift quality. I do not have a problem with the shifts. My problem is that there is a significant difference depending on engine temperature, which leads me to think I have a minor vacuum problem at one of the temperature extremes. I can perform some tests to solve my question but I was hoping someone had a similar experience that would narrow my investigation.

Again, the shifts are currently perfect in my opinion. The problem is the transmission engages very abruptly and forcefully (with a bang) when shifting from Park to Drive at operating temperature. All other transmission functions appear normal at both engine temperature extremes.

Oilburner; You haven't said anything about your engine speed. Are you idling too fast? Mine idles at about 600, maybe even a bit less with AC on and really goes into gear softly.

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Junqueyardjim
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1983 Mercedes W123 240D 4 Speed 285,000 on the road with a 617 turbo, beautiful butter yellow, license plate # 83 240D INDIANA

2003 Jaguar Type X, AWD. beautiful, good mileage,
Mom's car, but I won't let her drive it!

engine idles at just a hair over 700 rpm, which is where it should be if my memory serves. I believe the recommended range is 690-750 rpm. I think you are understanding my situation. It feels as if the engine was idleing much higher by the way it slams into gear. Thanks for your question. I tried lowering the idle some but I get a little shake at 650 rpm and it stumbles some after a cold start (below 40 F.).

Again for clarity, I only have this problem when the engine is fully warmed up, after at least a 20-30 minute drive, temp guage reads about 88C. Other than that, the engagement feels normal. Shifts are normal at all temperatures.

This rough engagement does not bother me much but my wife won't tolerate it. I do need to fix it, I'm sure it is causing unnecessary stress to the driveline and engine/trans mounts.