I've had a nuisance of a 'Tick-a tick-a tick-a' noise that sounds like it's coming from the rear of my '72 coupe. I only hear it above 20mph and while basically coasting (engine not pushing or holding the car back). Sometimes I hear it during deceleration. I can't really pinpoint what it could be. At first I was thinking it was my universals, but I got under the car and tried to twist the driveshaft back and forth and it's nice and tight. It's hard to reproduce as well and it doesn't do it constantly.

Some background... The rear end is a 10 bolt with 3.73's (I think) and an open differential with drum brakes.

Bear in mind that I have no experience with working on differentials. I have the basic knowledge of how everything works, but don't know about common problems. I was going to tear into it, but I didn't want to get into something over my head and end up having the car immobilized (since my wife's car is our only other source of transporation).

Thx- Bryan

Check first to see if the rear brake shoes are adjusted. An out-of-round brake drum can cause this kind of clicking. Does it go away when you apply the brakes?

Louie

Replace the springs that hold the brake shoes to the backing plates

Just remember that the u-joints can make noise and still be 'tight'. Pull the driveshaft out and inspect the joints for free movement and NO rust.

I had an identical problem with my 71 years ago (3.08s, open 10 bolt). I replaced everything. I eventually replaced the rear end with a used one from a wrecker. The problem went away and I never really new the cause. It may have simply been the brake shoes..... graemlins/sad.gif I do everything the hard ways some days. ;)

You don't have a rock stuck in the tire thread do you?

No, no rocks in the tire treads, and it's a distinct "tick-a" not just a 'tick'. It almost sounds like something in my hubcap (I have the washing machine center rallys on my car) but I've removed and inspected each one and made sure they were on nice and tight.

I've never really been able to tell if it goes away when I hit the brakes. I'm new to southern california, so when I have to apply them, I'm focusing all my concentration on people around me to make sure that they don't hit me and that I don't hit anyone. LOL

I'll give the brake drums a looking over and replace all the springs and components. As far as pulling the driveshaft, I've never done that before and wouldn't know where to start. I don't really have a lot of tools or a place to work on it since I rent and my chevelle barely fits in the sorry excuse for a garage that they provide.

Thanks for your help guys! graemlins/beers.gif

If it's a posi. the clutches maybe going.Mine went out awhile ago,jacked rear end up and turn tires one went oposite way.Made the same noise.

If it's not brake related might want to look there to.

Ive had the same noise..... ended up being the rally cap... I had checked for tightness seemed fine .. remove caps drive car ;)

If it's a posi. the clutches maybe going.Mine went out awhile ago,jacked rear end up and turn tires one went oposite way.Made the same noise.

If it's not brake related might want to look there to.I don't mean to be an ass, but:
Some background... The rear end is a 10 bolt with 3.73's (I think) and an open differential with drum brakes.So, I don't think that could be it.

I listened to it today on my way to work and it only does it if I'm in that little zone where the engine isn't holding the car back or accelerating. That little bit of time where the driveshaft is basically spinning without a + or - torque load. Never got a chance to try the brakes because it stops after I let off the gas.


Ive had the same noise..... ended up being the rally cap... I had checked for tightness seemed fine .. remove caps drive carYa know... that's something that I had thought of and never tried. I ought to to see if that's the cause. If it is, then I'll need to find out why it's clicking.

Thanks again guys!

I've seen this happen when there were two tires of slightly different diameter mounted on a posi rear. This was with a new set of Coker's OEM replica redlines on a 65 Chevelle show car. It didn't take much difference in height, these tires were the same size but just a little "off". After swapping tires the problem was gone.