I bought my 2004 maxima SL about a year ago. It had no issues and 103000 miles on it. Its got around 120000 miles on it now. When the car is cold is when i have the problems with the tranny. It shifts perfect from park to reverse and drive. No issues. It only slips slightly when Shifting from 2nd to 3rd gear. When the car warms up after about 20 minutes it doesnt slip as bad. I checked the fluid, was a little darker than cherry red but seemed fine. Does anyone have any ideas what my problem could be.

 

Do a fluid flush see if that helps. If not, you either have the clutch packs on their way out or its the valve body. If its the 5 speed, most likely valve body, but 04 SL did not come with a 5 speed.

 

sounds like your clutches are slipping. do the revs shoot up between shifts?

it can also be your valve body if its more of a bang than a slip between shifts.

good luck. Unfortunately, 6th gen trannies are week and show problems when the miles go over 100k.

Either way, it isn't a cheap fix.

 

I am not sure if thats the case. If the car has a shift tronic, it has a 5 speed. Some SL's came with it. Not sure if it was 2005 onwards or some 2004s too.

Do a fluid flush and put some seafoam transtune.

 

http://forums.maxima.org/7400151-post3.html

if you do have an early 2004 SL and a 4 speed auto trans then PM me.
Otherwise the 5AT problems are covered in the STICKY I linked.