NHTSA Complaint #10807482 — 2001 ACURA MDX

TWO ISSUES WITH DRIVE-TRAIN: FIRST IS A GRIND/RUMBLE (LIKE DRIVING OVER A HIGHWAY RUMBLE STRIP) FELT AT LOW SPEEDS (20-30 MPH) WITH LIGHT ACCELERATION. SHAKES VEHICLE SLIGHTLY. CAN BE REPRODUCED. VEHICLE CAN ACCELERATE THROUGH THE GRINDING/RUMBLING BY FURTHER DEPRESSING ACCELERATOR AND SOMETIMES ACCELERATES THROUGH THE 20-30 MPH RANGE WITHOUT NOTICEABLE GRINDING/RUMBLING. IF, HOWEVER, THE VEHICLE IS ACCELERATING SLOWLY AND IT DOES BEGIN TO GRIND/RUMBLE, MAINTAINING A CONSISTENT SPEED/RPM LEVEL (WITHOUT DRASTIC CHANGE IN ROAD SURFACE OR GRADE THAT WOULD CAUSE COMPUTER TO CHANGE GEAR DUE TO INCREASED/DECREASED FRICTION) THE DRIVER CAN CREATE A CONTINUED DURATION OF THE GRINDING/RUMBLING UNTIL RELEASING OF FURTHER DEPRESSING THE ACCELERATOR TO CHANGE OUT OF THAT GEAR/RPM/SPEED/LOAD COMBINATION WHICH RESULTS IN THE GRINDING/RUMBLING DESCRIBED ABOVE. THE SECOND ISSUE IS A WHIRRING/LUGGING DURING HIGHWAY SPEED CRUISING ON LEVEL SURFACE WITH D5 AUTOMATIC TRANSMISSION GEAR ENGAGED. ONCE THE VEHICLE ACCELERATES ABOVE AROUND 45 MPH, MORE CONSISTENTLY AT SPEEDS ABOVE 50 MPH, ON LEVEL TERRAIN AT CONSISTENT SPEED VIA ACCELERATOR OR CRUISE-CONTROLLED, THE VEHICLE WILL FREQUENTLY INCREASE BY APPROXIMATELY 200-300 RPM AND BEGIN TO MAKE A WHIRRING SOUND WHICH LASTS A FEW SECONDS THEN THE RPM RETURN TO PREVIOUS SPEED AND THE WHIRRING SUBSIDES. A FEW SECONDS LATER THE SAME THING OCCURS AND THIS CYCLE CONTINUES THROUGHOUT THE DURATION OF THE MAINTAINED SPEED. THE PHENOMENON IS MORE NOTICEABLE WITH CRUISE-CONTROL AS THE SPEED AND RPMS LIKELY HAVE MORE COMPUTER REGULATION BUT IT IS ALSO NOTICEABLE WITHOUT CRUISE-CONTROL ENGAGED. MY CONCERN IS THAT IN EITHER SITUATION THE TRANSMISSION INTERNALS COULD BE WORN IN A MANNER NOT INTENDED BY MANUFACTURER RESULTING IN OVERHEATING OR BREAKING OF INTERNAL COMPONENTS THAT COULD CAUSE A SUDDEN AND VIOLENT REACTION OF THE SPEEDING VEHICLE.