dshawster

I have a noise coming from the car that I'm pretty sure is the differential and it only happens when I decelerate, no noise when steady speed or under acceleration. I suspect the diff because I pulled it a few weeks ago to change the seals while I was swapping the rear spring, I set the pre-load at about 5 in-lbs but I'm wondering if I didn't get the pre-load just right if it would cause an issue like this. I want to confirm before pulling it again but I'm 95% sure it is the diff because its the last thing I touched! I appreciate any help in advance.
Also I just re-installed trailing arms rebuilt by Bairs because of a bad wheel bearing on the passenger side, this is originally what I thought the cause of the noise was.

Dave

toobroketoretire

Are you saying you replaced the 3rd member's side yoke seals and the pinion seal? A turning torque of 5 in/lbs is a lot lower than usual but it wouldn't cause a noise that I can think of. If a rear tire isn't inflated enough it'll cause more noise than usual so check the pressures. I recently found tires don't bulge hardly at all until the pressures drop to 5 psi or less so you can't tell by looking at them.

dshawster

I did replace the pinion and yoke seals, put friction additive back in and oil. The sound almost sounds like tire rub but I don't see anyplace where it would be rubbing. I will check the pressures to eliminate anything caused by that.

toobroketoretire

Sometimes the parking brake cables will rub the inside of the tires so check those too. They would be shiny if they were rubbing. The cause would be a missing retainer clip where the cable housing attaches to the trailing arm. Also if the transmission mount is broken the tail housing can shift back and forth sideways upon acceleration and deceleration so you could check that too. Are you running stock size tires?

About a month ago I started a thread "Tire Bulging At Low Pressures" after performing some tests in my garage. I found a tire hardly bulges at all until the pressure drops below 5 psi. So its impossible to judge the tire pressure by just looking at it. The more a tire bulges the more it rides on it's outer edges and that makes noise that resembles driving on a rough surface road.

dshawster

[QUOTE=toobroketoretire;1590910468]Sometimes the parking brake cables will rub the inside of the tires so check those too. They would be shiny if they were rubbing. The cause would be a missing retainer clip where the cable housing attaches to the trailing arm. Also if the transmission mount is broken the tail housing can shift back and forth sideways upon acceleration and deceleration so you could check that too. Are you running stock size tires?

Running brand new stock tires on stock rims. I'll check the mounts to eliminate that, its not the parking brake cables I just re-installed those yesterday and made sure they were in their mounts and had clips installed. I'm also leaning towards it being a u-joint, I had a similar situation in my truck years ago under deceleration, but the noise was a lot different.

LT-1 kid

I had the same type of noise from my 69 BB, it had a bad ujoint not fully seated
at the outer half shaft. also check the drive shaft ujoints

dshawster

I'm going to jack it up tomorrow and take a look at them, I hope it isn't the diff.