87 Rear "Clunk" normal?

[8t7vette]

Well after finally acquiring the two rear hub assembly bolts and getting it reassembled I took it for a spin last night. As I was slowing down to a stop I could hear a "CLUNK" from the passenger rear wheel area. The clunk seemed to occur during the 2-1 downshift. I didn't hear the noise from the left side.

I've always previously noticed a "clunk" as I was coming to a stop. At times I thought it was the transmission, other times I thought it was the u-joints or maybe the wheel bearings. I figured after doing all the u-joints and bearings this would be eliminated.

Considering the entire rear was out for bearing replacement, poly bushings, u-joints and 2.59 to 3.75 gears and I am about 99% sure everything is torqued and fastened correctly....I'm am wondering if this noise is natural.

I do not recall hearing it last week-of course at that time of driving it I had two snapped wheel assembly bolts. I do know the transmission(automatic) had some sort of rebuild work done to it at some point before I bought it.

Is this noise normal during deceleration? I don't think with the two broken hub assembly bolts that I could have damaged the Spicer u-joints on the axle shafts. One other note is when I put the new bolts in I also swapped and put in a new rear wheel bearing assembly just in case something could have happened to the other one when the bolts were broken.

Thanks

Toby

 

[86PACER]

It is my understanding that all automatic C4's have a "clunk" upon deceleration. That is normal. Mine has always had it before and after my trans was rebuilt. That is the transmission downshifting when you are coming to a stop. You can't always hear it, it depends on how fast you decelerate. There is a difference between the automatic transmission "clunk" and any other rear end "clunks", you just have to know what the trans clunk sounds like by ear to be able to tell them apart.
The only way of distinguishing the clunks besides by ear that I know of, is to observe the frequency of the clunk.
The normal auto trans clunk will only be heard about one time upon deceleration.
If the clunk is heard multiple times upon deceleration, it's not the normal trans clunk, it will be something else.

 

[Vettefan87]

Mine will also do it on accasion it depends on how fast I decelecerate if it clunks or not.

 

[vetteboy86]

How about a clunk when shifting gears in an auto. Or a clunk when accelerating?Thats my problem.

craig

 

[vetteboy86]

I guess it is just me but I consider the corvette to be a world class automobile, and a sports car at that. It is hard for me to believe that any kind of clunk is normal. That is just me.


Craig

 

[First C4]

Lets put it this way, my 86 with 24,000 on it has a light clunk not always noticable during the 2-1 downshift. There is also a clunk for reverse and a clunk for drive. Drive being the lighter of the two. I had it checked out by a competant corvette only shop and their answer was normal for the C4.

 

[NevadaJim]

A 'clunking' sound when you first put it in reverse/drive, could be bad drive shaft u-joints. Could also be a problem with your tranny, but I'd start by inspecting the u-joints.

EDIT: Sorry, should have read your post more closely (its early here). I see you have alread replaced the u-joints.

 

[First C4]

According to Corvette shop, the sound is normal. They said if it gets louder then worry. Some sound from the joints is normal, it does not occur each time I go into reverse.

 

[First C4]

Besides I have only 24k

 

[vader86]

Clunking sounds when going into gear, from the rear end, are likely worn U-joints. Some slight clunking is normal, but if it becomes a real jolt, check the joints.

You should replace all of them if any are bad, theyre about $20-25 each, and you should ONLY GET SPICER COLD FORGED joints.
Theyre the only ones that can handle the torque.

 

[vetteboy86]

I thought I had more then the normal "clunk". However the car was at the local corvette shop, because I was tired of chasing a ghost. They said nothing was wrong with the car, and drive it until it gets worse, that is if it does get worse.


Craig