A few days ago I purchased a 1994 940 (non-turbo) with 156K miles on the clock from a 50-ish woman who had it 5 months. Looks like she purchased from a small car lot, but there was no name, and there are no service records.

The car starts/runs/idles/drives just fine, no overheating, and transmission shifts fine, except there is a slight clunk (no delay) when I shift from P>R and R>P. I would say it's a step above "barely noticeable". Also, there is a slight lurch in the last foot or so of coming to a full stop.

I checked the transmission fluid and the level is fine, but the fluid is a dark color, about the same color as old motor oil (I doubt the previous owner accidentally poured motor oil into the transmission or it would have burned out by now). There are no filings or flakes in the tranny oil.

So I took the car to EconoLube where they changed the motor oil. The manager warned me that it was a 50 percent chance of harming the transmission if he changed the tranny fluid, so I did not have it changed. I had heard long ago that changing the fluid could harm an older car's tranny that hadn't been serviced in a long time.

So I need advice: should I take a chance and get the tranny fluid changed? I read that changing the fluid still leaves about 40% of old fluid in the system (torque converter etc.) Is this true? Even if I do change the fluid, does the dark fluid color indicate a problem like coolant getting into the system?

Is there a test a shop can do to see if coolant is in fact getting in there?
Is the last-second lurch a symptom of the tranny or the brakes?

My 940 will not be seeing heavy usage. Just a couple of six-mile roundtrips a day, half freeway/half streets, and errands. I anticipate about 6K miles/year. There won't be any heavy loads either.

My other 740GLE I've had for about 8 years, and after 23K miles the tranny fluid is the proper red color. I want to keep the 940 for a long time.

Any advice from you folks is really appreciated!