i have a 1995 volvo 940 sedan and the over drive is acting up relay seems to be working fine is it possible that all it needs is a trans flush and filter change and if so autozone has 2 diffrent styls of filters for my year and model they are one says for transmission type AW30-40LE and the other says for AW71 transmissions everything in my car is stock and i dont know what model transmission i have please help

 

You should have an AW70/71 but I seriously doubt fluid and filter will resolve your OD issue. What makes you "seem" to think the OD relay is working? Can you hear it click? Does the shift light in the dash turn on and off w/ the shifter switch? Generally, if the answers to the above are yes, the problem is the actual wire under the car leading from the shifter to the overdrive solenoid mounted on the side of the transmission. Road debris, years of ol and tranny fluid can really do a number on the insulation and the wire and it can ground out on the chassis or completely break.