does anyone know if the newer 4spd auto will swap into my 3spd equipped 2001 without much modification? if not why? Thanx

 

it will fit but you will need a valve body from a 4spd neon and the ecu from a 4spd and you should do just fine you may find little things along the way but nothing extreme

 

will it make a big diff. in speed? and if so, will it be acceleration or just speed as far as increasement and how much as far as auto/trani? stupid question, but i have an 02 neon se, how do i know if its 3 or 4 speed?

 

Just count how many times it shift during WOT to see how many gears you have...the 4spd is "quicker" by comparison, but for the same price you might as well go for the 5spd. manual swap and you'll see much more gain...