Upon accelerating from a standing stop or coming to a complete stop there is a fairly loud dull thud from the back of the truck somewhere. I recently completely rebuilt the posi rear end, replaced the leaf springs and shocks, the driveshaft and U-joints are new as is the transmission and all mounts. I took it to a frame shop and had it inspected with no problems found, even though they did hear the noise. The noise itself is random, some days it only does it once or twice, while other days it's every time you start or stop. It has made this noise both before and after the rebuilds. I've had two shops and one GM dealer tell me this is 'normal' and to just ignore it. I find that hard to believe, so I was wondering if anyone has any ideas on what would cause a dull thud like this.
2007-01-01 18:13:36 · 7 answers · asked by Anonymous in Cars & Transportation ➔ Car Makes ➔ Chevrolet
without hearing it to me from ur info it sounds like u may have a issue with ur exhaust to close to the frame or to loose or even to tight at the mounts thats where ided start to check remember ur exhaust moves when u accell so at least check it and u may be surprized good luck hope this helps
2007-01-02 05:15:41 · answer #1 · answered by Anonymous · 0⤊ 1⤋
Was this thud there before all the overhaulin' was done? If it wasn't I would suggest looking at all the mounting bolts and bushings for the rear axle assembly. Next I would get involved with the exhaust system for clearance issues or worn/broken hangers. Then check for a possible problem with broken baffles inside the muffler or even the pipes. Even shocks or their mounts have been known to produce pops and knocks. Is there a possibility of having something bouncing around inside the brake drums? I have also seen problems in steady bearings, U-joints, or even a driveshaft that was coming apart inside. These are tough to diagnose and we always found that more eyes and ears were better than just one set. Good Luck.
2007-01-02 16:32:26 · answer #2 · answered by Deano 7 · 0⤊ 1⤋
A certain amount of drive line "clunk" is typical. Or so GM officially states.
You might try this. Remove the drive shaft and lubricate the splines of the slip joint. Use a good lithium based grease.
This procedure was actually recommended by Gm during the late 80' early 90s for the condition you describe.
Hope this helps.
2007-01-02 06:22:35 · answer #3 · answered by Mike 3 · 0⤊ 2⤋
It could be one of the following.
1. A broken pinnion snubber allowing the third member to hit the bottom of the vehicle
2. A broken trans mount allowing the trans to smack the bottom of the vehicle.
Both of these produce a thump on acceleration or braking sometimes.
2007-01-02 02:48:32 · answer #4 · answered by BIG-IRON 3 · 0⤊ 2⤋
Hey Bud, I ain't heard of this one before, ya looked at the body to frame mounts ? How can they tell ya to ignore a freakin 'THUD' ?
2007-01-02 02:39:29 · answer #5 · answered by Anonymous · 0⤊ 2⤋
sounds like you have a limited slip diff. if this is the case,the thud you hear is the diff clutch pack. the make a special additive to prevent this.
2007-01-02 10:02:35 · answer #6 · answered by DASH 5 · 1⤊ 2⤋
try taken your bowling ball out of the back, then try it. LOL
it may be your gas sloshing around????
2007-01-02 09:26:21 · answer #7 · answered by Big Tim 2 · 0⤊ 1⤋