Chevrolet Repair: Transmission, chevy astro, friction modifier

Question
Have a 1997 Chevy Astro 2WD van. After about 30 miles of highway driving and getting back into town, transmission shifts very very hard from 1st to 2nd gear.

Answer
Hey,

 You need to have the computer scanned for codes.  It sounds like it may be going into a limp in mode.  If a trans component slipping code is setting over time on the highway when you get into town the PCM is trying to protect the transmission by increasing line pressure and extending shift timing.  This lowers internal slippage and helps protect clutches and seals.  In some cases general wear and tear cause this.  You should have the transmission serviced with a new filter and fluid.  A friction modifier is available to help correct this problem.

Wayne