1988 GMC S15 shimmy at high speeds

BULLOCK

MEMBER
1988 GMC S15
4 CYL
2WD
MANUAL
109,000 MILES

My 1988 GMC S15 shakes when I get up to speeds of 50mph and up. Its worst is at about 55mph. I just had 4 new tires put on it thinking it would solve the problem but it didnt. It starts violent and tapers off and then starts again consistently at these speeds. The alignment hasnt been done but the truck still drives straight when I take my hands off the wheel. Could it still be the alignment? If not, what else could cause this problem?

1 Reply

HMAC300

MECHANIC
48,601 POSTS

Alot of things can cause shaking. I'd check the driveshaft for a weight falling off or if you have a center support due to a 2 piece driveshaft i'd check that. Also broken motor mounts, trans mounts as well as a wight falling off on the troque converter or abroken flex plate. All of this along with a front end problem.