SHIFTING PROBLEM PLEASE HELP

[bdes64]

I have a 92 Nissan Maxima GXE. Automatic Transmission. I was doing about 30 and was cut off by a van, I slammed on the brakes and avoided an accident. However, the car will not shift into I belive is 3rd gear. It just seem to go up to 5000rpm and will not shift into a higher gear. PLEASE any advice will be greatly appreciated..
Bruce

[loystock]

Any maintenance history? When was the last time the transmission was serviced? Please check level and condition of transmission fluid. If the fluid is dark and/or smell burnt, it must be replaced (by flushing or multiple drain and refill).