W124 vibrates every now and then

[Robin Teo]

Hi gentlemen

I have year 91 w124 with auto transmission. Recently, I have got the ATF changed. However funny reaction from the car started to surface.

Firstly, the auto gear will drop from gear 4 to gear 3 at cruising speed for obvious reason. When I slowed down the car and pick up speed again, the auto trans would not move on to the gear 4. I pull over and turn off the car for a second. Turn on the car and drive on, and the gear works fine. Howevr, the problem happen again after driving for a couple of minute at cruising speed. I went back to my mechanic who did the ATF change and he said he did the usual work and usual type and usual amount of ATF. Nothing extraordinary. The weird thing is when I drive for 200km to visit a friend, this problem kept surfacing and I had to repeat the procedure several times to get to my destination. On the way back for the return 200km, it was a cruise and nothing of the gear problem surface. What is the problem??

The other wierd behaviour of my car now is that the car will shudder and vibrate for a couple of minutes each time I start and drive the car in the morning. The car will vibrate no matter what I select on the auto trans. Park, Neutral and gear engage, it still vibrates. It will stop after I drive for a couple of minute when I am on the road. Even after I have been driving the car in the hot afternoon or evening when I am enjoying the drive, the car will suddenly start to vibrate again. I will keep on dring and the vibration will go awy by itself after a few minutes.

I cannot tell where the vibration come from. Whether it is from the front or from the underneath. It is just the whole car. The engine mounting is ok. I spoke with my mechanic and he is at a lost too. Help is required. Anybody out there? Thanks in advance.

Robin Teo