I have a "94 940 auto. There is a high pitch buzzing sound (under the car) when i accelerate and almost no power. When i put it in reverse it did not move until i accelerated and even then it barely moved. When I turned car off and restarted it the problem was gone temporarily. When i came to a full stop at lights a few minutes later the acceleration was jumpy and slow and sounds was back. Is this a transmission problem? Have had this car for 6 months and never checked the transmission oil. When i checked it today it seemed almost over filled??

 

Simply anwswering your question. yes. it could be the transmission. without driving the car or a video at least. really had to impossible to say what the problem is with the information given.

codes?
recent service or repairs?

 

No codes showing. No work done recently. It happens the most when i accelerate from a stop. High pitch sound increases the more i try to gas it. I literally pulled off the road turn the car off and on again and it wasnt happening for a while.

 

Are your brakes OK? It may be brake related--definitely check that before the tranny. A broken pad, a hanging caliper, many things can make that noise, and since you say 'no power', may be some brake component is dragging...

 

I'd get it up on a lift or at least 4 sturdy jackstands, put it in neutral and spin the rear wheels by hand, see if anything is binding or what or any odd feeling or sounds from the tranmission or differential.... if thats ok, start it, and carefully put it in drive without giving it any gas (this is where very sturdy jack stands are a MUST), and see if the tranny sounds ok. if you hear your buzzy sound, get under the car and try to localize where its coming from (differential, drive shaft, transmission, or rear wheels).

 

In addition to what Pierce stated, the buzzing could also be the in tank fuel pump on its way out

 

indeed, or a whiny main fuel pump. my main was quite loud at times when my tank pump went out. I also had full throttle fuel starvation issues when I had less than 1/2 in the gas tank. and really poor running with 1/4 tank.