Chevrolet Repair: steering sway, steering linkage, center shaft

Question
I have a 99 chevy van that sways back an forth kind of like when your car starts to fishtail and you countersteer but it keeps swaying. I noticed there was  some play on the steering box arm. Is there a way to tighten it up?

Answer
HI GAB, YES YOU CAN TIGHTEN UP THE BOX,BUT BEFORE YOU DO THIS YOU HAVE TO HAVE AT LEAST 3/4 TO 1 INCH OF FREE PLAY IN THE STEERING WHEEL SIDE TO SIDE WHEN ENG IS OFF. CK THIS FIRST.IF YOU TIGHTEN THE BOX TIGHTER THEN THIS IT WILL NOT STEER CORRECT,IF YOU TURN TO THE RIGHT OR LEFT SLIGHTLY IT WILL STAY THERE CALLED [MEMORY STEER. THIS IS NO GOOD. TO ADJUST THE BOX  GO TO THE TOP SIDE OF THE BOX YOU WILL SEE A NUT 9/16 OR 5/8 LOOSEN THIS AND HOLD THE CENTER STUD WITH A ALLEN WRENCH,TURN THE ALLEN WRENCH CLOCKWISE A 1/4 TURN AT A TIME TO ACHIEVE 3/4" OF PLAY IN THE WHEEL. THEN TIGHTEN THE LUCK NUT WHILE HOLDING THE CENTER SHAFT WITH THE ALLEN WRENCH. THATS IT.. BUT CK THE STEERING LINKAGE FIRST, HAVE SOMONE GET IN THE VAN AND TURN THE WHEEL LEFT AND RIGHT FAST MOVEMENTS WITH THE VAN OFF 1 TO 2 INCHES OF WHEEL MOVEMENT WHILE YOU LOOK AT THE CENTER LINKAGE FOR MOVEMENT,YOU WILL MORE THEN LIKELY SEE MOVEMENT IN THE CENTER LINKAGE JOINT OR TIE ROD ENDS...DOING THIS YOU WILL BE ABLE TO SEE ANY KIND OF LOOSENESS IN THE STEERING LINKAGE,REPAIR THIS AREA FIRST..ALSO CK ALL THE AIR PRESSURES IN YOUR TIRES. MAKE SURE THEY ARE ALL SET CORRECT. ONE LOW VERY TIRE WILL CAUSE THIS AS WELL. GETTING BACK TO THE STEERING GEAR BOX AGAIN THEY USUALLY DO NOT NEED ADJUSTMENT..IF IT IS THE BOX THE WORM GEAR IS PROBABLY NO GOOD. TIME FOR A REBUILT OR USED BOX..REBUILT BOX, ABOUT $150.OO OR SO. IF YOU NEED MORE INFO GET BACK TO ME,I HOPE THIS HELPS YOU... PLEASE WHEN YOU LEAVE THIS SITE COULD YOU RATE MY ANSWER GOOD OR BAD. THANK YOU,,, TOM..