Rear End Noise
Thread Starter
3rd Gear
Joined: Jan 2022
Posts: 3
Likes: 0
From: Cape Girardeau, MO
Rear End Noise
I have a 68 with a 427, 4 speed. There is some noise coming from the rear end, particularly when I make a left turn from a complete stop. I am a new C3 owner.
Any thoughts or ideas would be appreciated.
Any thoughts or ideas would be appreciated.
Melting Slicks
Joined: Nov 2006
Posts: 3,411
Likes: 1,821
From: Apple Valley, MN
The most common, but not always, cause of the noise you describe are the positraction clutches chattering. The simplest action is to siphon out the fluid (there are no drain plugs on the stock differential) and replace with a high quality gear oil (Lucas 85w140) along with two bottles of positraction additive (AC Delco 10-4003).
That said, does the noise occur when turning right? Find an empty parking lot and do some slow, tight figure eights. Those turns force the spider gears to turn in the differential which exert force on the positraction clutch plates. When you are driving straight, those spider gears don’t turn so you would not hear noise from that source.
Another common noise source is the front snubber bushing badly worn.
Do you have any idea if the differential is original to the car? How many miles on it?
That said, does the noise occur when turning right? Find an empty parking lot and do some slow, tight figure eights. Those turns force the spider gears to turn in the differential which exert force on the positraction clutch plates. When you are driving straight, those spider gears don’t turn so you would not hear noise from that source.
Another common noise source is the front snubber bushing badly worn.
Do you have any idea if the differential is original to the car? How many miles on it?
