There are 3 owner-reported powertrain & transmission complaints for the 2003 Pontiac Grand Prixin NHTSA's database. These are unverified consumer reports and may not reflect confirmed defects.
I PURCHASED A 2003 PONTIAC GRAND PRIX SE WITH A V-6 AND I GET WATER COMING IN THE PASSENGER SIDE EVERY TIME IT RAINS. ALSO THE TRANSMISSION SHIFTS HARD OCCASIONALLY WHEN GOING FROM FIRST TO SECOND GEAR. I WAS TOLD TO FIX THE LEAK WOULD BE AROUND $300 AND THE TRANSMISSION PROBLEM.... I MAY AS WELL BUY ANOTHER CAR FOR THAT PRICE.... *TR
IN 2003 I PURCHASED A NEW 2003 PONTIAC GRAND PRIX 3.5L V6 WITH AUTOMATIC TRANSMISSION. I HAVE HAD IT SERVICED REGULARLY WHEN THE INSTRUMENTS HAVE INDICATED AND THE OWNERS MANUAL HAS SUGGESTED. AT APPROX 59000 MILE I HAD TO HAVE THE TOP AND BOTTOM HEAD GASKET SEALS REPLACED, AND THE AIR CONDITIONER COSTING $2500.00. THEN AT 68000 MILES THE TRANSMISSION WAS SLIPPING AND HAD TO BE REBUILT AT A COST OF $3000.00 (SEVERAL PART ALONG WITH TORQUE CONVERTER). IN EACH CASE THE MECHANICS STATED THAT THIS IS A KNOWN PROBLEM WITH THE VEHICLES AND THAT THESE PARTS WERE INFERIOR. NOT TO MENTION THAT I WAS SOLD THE VEHICLE WITH A SOON TO BE OUT-DATED ONSTAR SYSTEM EVEN THOUGH GM NEW IT WOULD NEED REPLACE WITHIN A COUPLE OF YEARS. *TR
I BOUGHT A 2003 GRAND PRIX WITH IN THE FIRST YEAR I HAD TO REPLACE THE TRANSMISSION THEY CHARGED ME 1300.00. *TR
Complaints are unverified consumer reports submitted to NHTSA. A high complaint count may reflect vehicle popularity, not defect severity. Data sourced from NHTSA public records.
Data synced from NHTSA on Apr 25, 2026