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73-87 Chevy _ GMC Trucks => 73-87 Chevy & GMC Trucks => Topic started by: 1981 ss chevy on December 15, 2009, 07:08:47 pm

Title: Clunking noise???
Post by: 1981 ss chevy on December 15, 2009, 07:08:47 pm
My 81 stepside makes a clunking noise when im driving over bumps or when pull into a driveway thats on a slope or a small angle.  It sounds like its under the floor board on the driver side but it varies sometimes.  Its not my exhaust and all the crossmember bolts are tight my shocks are loose.  Anybody got any ideas??
Title: Re: Clunking noise???
Post by: Layne on December 15, 2009, 08:08:07 pm
my shocks are loose. ?
That may be it. or is that a typo?
Title: Re: Clunking noise???
Post by: hotrodpc on December 15, 2009, 08:25:53 pm
I would want to rule out broken trans mount if I were you.
Title: Re: Clunking noise???
Post by: Irish_Alley on December 15, 2009, 08:52:44 pm
also if none of the others check out could be a broken spring
Title: Re: Clunking noise???
Post by: Lt.Del on December 15, 2009, 09:53:04 pm
hotrodpc may have hit it.  I used to have a noise when turning sharply.  Come to find out the rubber trans mount insulator was broken and the trans moved when the truck turned suddenly and the driveshaft yoke was hitting the cat converter heat shield.
Title: Re: Clunking noise???
Post by: Blazin on December 15, 2009, 11:31:17 pm
If not that I would check the cab mounts.
Title: Re: Clunking noise???
Post by: 1981 ss chevy on December 16, 2009, 08:36:18 pm
i when the truck is in park on a slope and not running i can rock the truck and it makes that noise too now i noticed, and where are the tranny mounts at??
Title: Re: Clunking noise???
Post by: Lt.Del on December 16, 2009, 08:42:49 pm
tranny  mounts are in the crossmember under the tranny...it keeps the tranny in place.  There are only two points that hold the tranny in place, the engine block and the crossmember. There are two rubber insulator things that two 9/16" (or is it 5/8"...dont' remember) bolts bolt into them to keep them still.  The rubber sometimes breaks and it becomes free floating=not good.
Title: Re: Clunking noise???
Post by: ccz145a on December 16, 2009, 09:15:58 pm
Mine had that sound when the upper control arm bolts came loose and All the shims fell out.
Title: Re: Clunking noise???
Post by: 1981 ss chevy on December 16, 2009, 09:19:50 pm
but if it was my tranny mounts wouldnt it only make noise when i was giving it gas or taking off hard? i mean im gonna check them anyway but im just wondering
Title: Re: Clunking noise???
Post by: Lt.Del on December 16, 2009, 09:35:29 pm
The way you elaborated on the noise since my original post makes me steer a little away from that. But, it is a very simple check.  Get under the truck and grab hold to the trans tail and try to move it up, down sideways.  You'll know if the mounts are broke.

Check suspension parts as mentioned.  Check shock mounts....the nuts may come loose.  Check exhaust line for knocking. Check engine mounts.  It should be easy to diagnose if you spend a little time on your back.
Title: Re: Clunking noise???
Post by: 1981 ss chevy on December 16, 2009, 09:49:56 pm
will do i gotta wait til tomorrow its to chilly outside here i need to invest in a heated shop haha but ill check tomorrow and ill let you know thanks
Title: Re: Clunking noise???
Post by: hotrodpc on December 16, 2009, 10:03:21 pm
Reason I suggested Trans mount is you said the noise is coming from the floorboard and you know its not exhaust etc. As Sgt says, just get under the truck, and push up on the tail of the trans, or push it to either side. You'll know if its broke. Sometimes its even evident without pusing on it, it will be half off the mount in some cases. If thats not it, then do check your suspension bushings as suggested.
Title: Re: Clunking noise???
Post by: 1981 ss chevy on December 17, 2009, 08:05:11 pm
i checked the tranny and all suspension its all tight in working order im just stumped now anymore suggestions??
Title: Re: Clunking noise???
Post by: hotrodpc on December 17, 2009, 09:51:54 pm
Noises like that will play tricks on you. And you said you are certain its not exhaust pipes? And its a clunk coming from under the truck when you slow down or go over a bump? How about U jonits or carrier bearing if its got a 2 piece driveline?
Title: Re: Clunking noise???
Post by: Grover 1 on December 17, 2009, 09:58:09 pm
Have you checked the shocks?  I had a clunk like that and it was a bad shock bushing, sounded like it was coming from the floorboard.
Title: Re: Clunking noise???
Post by: Lt.Del on December 17, 2009, 10:01:01 pm
Quote
when the truck is in park on a slope and not running i can rock the truck and it makes that noise too now i noticed,

do that and chaulk the tires well.  Get up under the truck while someone rocks the trucks.

also, jack up under the frame taking weight off the wheel, one front side at a time, and just rock the wheel and push up on control arm and move it as much as you can til you see what has play in it.
Title: Re: Clunking noise???
Post by: hotrodpc on December 17, 2009, 10:16:15 pm
I'll agree with Sarge here. It is very hard to check suspension when its on the ground, and if you are by yourself. Truck sitting motionless with the weight on the parts, its hard to find a loose suspension parts. You can also jack the frame up in the front to where the tires about 2 inches off the ground, get you about a 4 ft 2x4 and put it under the tires and use the 2x4 as a pry bar and lift the tire and have someone watching your bushings for excessive movement.
Title: Re: Clunking noise???
Post by: 1981 ss chevy on December 18, 2009, 06:21:28 pm
thanks you guys it was a bad bushing after all your tips are greatly appreciated
Title: Re: Clunking noise???
Post by: hotrodpc on December 18, 2009, 11:00:28 pm
Awesome !!! You're 50% done just knowing what it is. Have you started the install yet? Which bushing is it?
Title: Re: Clunking noise???
Post by: 1981 ss chevy on December 25, 2009, 01:45:17 pm
it was the driver side front shock the bushing that is actually inside the shock itself if you kno what im talking about its hard to explain lol well i just put new shocks up front and now its all smooth noiseless sailing
Title: Re: Clunking noise???
Post by: hotrodpc on December 25, 2009, 07:27:57 pm
I know exactly what you are talking about. See, those noises do play tricks. You thought it was under the cab. I tell people stuff like that all the time. No, its not that, its coming from here or there. Just like roof leaks. Its not leaking where you see the puddling in the ceiling like many think.
Title: Re: Clunking noise???
Post by: 1981 ss chevy on December 26, 2009, 09:58:57 am
exactly right