1989 Volkswagen Jetta • 4 cylinder FWD Automatic • 110,000 miles

1989 VW Jetta 1.8 F/I mileage: 110,000. Every time I am driving rather "spirited" and I wind the engine up beyond 4000 RPM, the engine/transmission noise changes from a high-pitched noise as seems normal, to a low deep rumble. In general, the car also begins to vibrate a lot more. It seems that it is only at 4000 RPM and above, and only when the car is in drive. I talked to the dealer and they said, "don’t run it above 4000 RPM (not a lot help). Anyway, the only thing that I can think of is that when it began was right after a very long road trip, say around 1500 miles. I changed the transmission fluid from whatever was stock to Redline MTL. Any thoughts or ideas would be appreciated, thank you for your time.
October 12, 2010.

Try changing the transmission fluid back to the brand recommended by the factory and then drive it for a couple of days. If your problem persists, your transmission may be ready for an overhaul.

Oct 13, 2010.