SKULLMAN

the trans. acts fine when the temp is low but after about 5-6 miles it shifts sluggish.it almost seems like it doesn't go to low gear until you completely stop.i think it may be shifting from 2nd to overdrive at times.the fluid needs changing but will that fix the problem.i can't find any info on the location of this solenoid except that it's inside the trans.if i drop the pan how will i know which one it is.the scan tool i used is older but trusted.does shift sol."a"refer to a specific one or is there only one shift solenoid?this is the first jeep i have ever owned and the first auto trans problem ever so i'm kinda lost.any insight and advice would be great as to what i need to do to fix this problem.also how long do i have to fix this before catastrophic failure occurs as this is my only way to and from work.thanks in advance for any help and advice.prefer seasoned mechanics info. no b.s.