2003 Grand Prix GT hard shifting, then jerking.

SOURCE: 2001 Pontiac Grand Prix Gt not shifting into OD

this trans is the 4T65E. It needs a 4th clutch hub. The splines strip off around 120k or more because they weren't hardened from the factory. The new ones have the hardened splines. The trans needs to come out and be partially torn down. I've fixed alot of these. Change the EPC solenoid while you are there. They wear and hang up causing intermittent harsh shifts

You can drive them forever without changing the hub but you'll never have 4th gear

SOURCE: i have a 2003 grand prix gt and its not shifting

it can be many things.make sure to check transmission fluid.if all is good.your governor valve sticking.or got worn gears.you have sticking or binding accumulator valve. 3 -2 control valve - tv limit 1 -2 or 2 - 3 shift valve train - sticking or binding throttle valve and plunger.2 -4 servo seals leaking - damage or worn 3 - 4 accumulator piston.the 2 3 4 clutches worn or the 3rd roller clutch is damage or missing bearings.Try changing transmission fluid and filter.put some of the transmedic transmission conditioner in fluid.dont over fill tranny.if you got sticking shift valves .it will loosen them up.so it will shift better.if it dont help you have internal transmission problems. .

SOURCE: 2003 Grand Prix GT - power windows

NEED TO CHECK ,MAIN POWER SOURCE ON DRIVERS DOOR OR MAIN CONTROL

SOURCE: 2002 pontiac grand prix gt surges when idling and

CHECK ALL YOUR VACCUM HOSES. CHECK FOR CRACKED OR SPLIT HOSES. MAY ALSO HAVE A BAD COIL PACK. PULL ONE SPRK PLUG WIRE OFF AND SEE IF PERFORMANCE IMPROVES. ANOTHER IDEA IS TO GO TO HARBOR FREIGHT AND BUY A SPARK PLUG CHECKER. IT COSTS ABOUT 3-4 DOLLARS AND THAT MAY BE THE ANSWER TO YOUR PROBLEM.

SOURCE: grand prix torque converter locks up too soon

Either the speed sensor, TCC solenoid , ECU or a stuck check ball in a lockup plate. I recommend taking this to a transmission shop this could get fustrating.

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