catching gears trouble

[riveramk2]

im new to the site n just purchased an SVX

one thing im noticing its doing is when im driving when it reaches abt 20 MPH the gear hits hard.....then at times when i hit 40 MPH it will delay catching the gear and my RPM will go from 2 to 4 in a heartbeat so i have to take my foot off the gas so it will catch it

like i said im new to the car its my first SVX i know somethings abt it im just concerned and seeing what it could be


also i noticed a dip stick with the initials DIFF i know that has to do with the differential bc of the AWD but could that be the cause of my problem??? what is that mainly for??????


thanks in advanced