How do I check my transmission fluid for a 2001 I30/Maxima? Do I need to warm the car up, and put it in Park and then check?

 

Check your owners manual OR read the stickies in the maintenance- Fluids & Lubricants forum.

 

You can check it either when it is warm or cold. The important thing is to have the engine running when you do...which means putting it into Park and engage the emergency brake.

There are two lines on the ATF dipstick -- one marked COLD, and the other marked, HOT. They refer to the temperature of the ATF. The manual suggests checking it at both times; i.e., once after just starting your car, and again, after you have driven your car for awhile (at least 5-10 minutes). The fluid line should be at or very near the corresponding marks.