I have a 1997 GT it seems to not like to shift out of second unless the engine is around 3000 to 3500 RPM. it stays in 3rd or higher as long as im not going slower than 40mph. No slipping problems or anything. Already dropped the pan changed the fluid and added some Lube guard to it. Didn't change much other than now it shifts around 3000 rpm now. Not really too sure what to try next. A mechanic friend mentioned shift solenoids.. Any advice? Thanks.