Automatic Transmission problems

[aikiwoce]

I've recently been having some issues with the automatic transmission in my 1990 Nissan 240sx LE. It started off as hard shifting from 1st to 2nd, and not shifting into 3rd overdrive until it was warm.

In the past few days it has started to "slip" randomly during acceleration only to catch a second later, sometimes 2-3 times in a row. It also seems to fluctuate between overdrive and the non-overdrive while maintaining maintaining speed. It feels like hitting a series of very small bumps repeatedly while driving down the road. It doesn't really shift out of OD, but it feels like it wants to. The other day it stalled at a Red Light. The problem seems to go away once the engine is warm, but still not completely.

Also, though it may be unrelated, I sometimes have problems starting the car, and have to "jiggle" the shifting handle the neutral switch senses the car is in neutral and able to be started.

What exactly could be causing this issue? Fluid levels, burnt fluid, sensors, loose wiring, and what steps should I take before taking it to a transmission shop?

[180fan]

Have a look at the fluid. It should be red and not stink. Sensors, probably wouldn't keep it from shifting hard. Have you recently disconnected that resistor up in the front of the car in the engine bay?