Nissan Repair: Auto Transmission shifting problems, nissan maxima se, nissan maxima

Question
I got a 1991 Nissan Maxima SE model with a VG30E engine. I noticed a change in auto transmission shifting.  The fluid level is topped off.  Normally I have the overdrive "ON" when I drive... I noticed that when I am over 40KPH its taking higher revolutions (+3000 RPM) before it shift to the next gear whereas before its not like this. Sometimes when I reach 60KPH, i have to maintain 2500 RPM to keep my speed.

I tried switching my overdrive "OFF" and the problem I notice is just the shifting after I reach 40KPH. When I reach this speed, it would take 3000 RPM or higher before it shift to the next gear.

Is this a case of a defective automatic transmission 'revolution sensor' or are there other causes?

Thanks.

Answer
Hi Mike,

You didn't mention if there was a check engine light on or not, but I suggest you take it to your nearest Cottman transmission shop and have them preform their diagnostic service. It's free. That transmission is fully electronic and computer controlled. There are dozens of sensors and solenoids that all must be working to make it shift properly.