I have a 2004 Maxima sl my 4 speed auto tranny just took a crap. Not engaging into any gear. Found a 5 speed auto tranny from a 2004 se. Is it plug and play or does it require a new ecu/harness? Tia

 

Coming from two different manufactures, the 4-speed and 5-speed have little in common. You'd certainly need new tcm and harness.
If you asked me, I'd say you should get another 4-speed transmission. The valve body of the 5-speed has an infamous reputation.

 

Now another question I know the RE4F04B came in a few cars, like the 02-06 Altima 2.5l and the Infiniti I35 and the quest. I know the bellhousing is different for the 2.5 to the 3.5. Can I change bellhousing and call it a day? Altima trans are much cheaper than the maxima. Also is the I35 trans plug and play? All connectors and mount location?

 

Ok I did read on that. Thanks for the info