Another 1979 Differential Question Thread
Thread Starter
Intermediate
Joined: Aug 2012
Posts: 28
Likes: 1
Another 1979 Differential Question Thread
Have read dozens of threads over the years but have not come across what I am experiencing.
Can this be the differential or something else?
When I am about 30 minutes into driving the car I get a groan coming from the rear, left side. This groan does not exist until the diff is heated up. The groan is obvious when I start lifting my foot off the clutch pedal in first gear and (maybe a bit more) when going into a turn and releasing clutch pedal.
I have new half shafts with new u-joints, new spring, new shocks and new strut rods.
What I find a bit weird is when I cut the engine and coast, swerving left and right...I am not hearing anything. Wheels rolling and swerving the car there is nothing at all. When things are cold it appears to be silent. 30 minutes into a ride and things heat up and the sound is obvious.
I do not think it will be ball bearings (while original) it would be constant even when coasting, engine off, hot or cold.
Would the clutches in the rear make this noise when hot only? and under torque only? Yes, I the rear has had a dose of the additive.
If not the rear what would cause this groan when the car gets hot only?
thanks
Can this be the differential or something else?
When I am about 30 minutes into driving the car I get a groan coming from the rear, left side. This groan does not exist until the diff is heated up. The groan is obvious when I start lifting my foot off the clutch pedal in first gear and (maybe a bit more) when going into a turn and releasing clutch pedal.
I have new half shafts with new u-joints, new spring, new shocks and new strut rods.
What I find a bit weird is when I cut the engine and coast, swerving left and right...I am not hearing anything. Wheels rolling and swerving the car there is nothing at all. When things are cold it appears to be silent. 30 minutes into a ride and things heat up and the sound is obvious.
I do not think it will be ball bearings (while original) it would be constant even when coasting, engine off, hot or cold.
Would the clutches in the rear make this noise when hot only? and under torque only? Yes, I the rear has had a dose of the additive.
If not the rear what would cause this groan when the car gets hot only?
thanks
Thread Starter
Intermediate
Joined: Aug 2012
Posts: 28
Likes: 1
Thread Starter
Intermediate
Joined: Aug 2012
Posts: 28
Likes: 1
I say it comes from the left side because that's where I am sitting. Hell, there's not much difference between left and middle LOL.
Will the bearing behave this way when it gets hot? There is no noise when coasting (engine off) and swerving left to right. Only when starting from a stop. One can argue it appears to be a bit worse when turning left but it is just as bad when moving forward.
I find it interesting that when I get to my destination 30 minutes away I think I need to call a tow truck to get home. Let the car sit and it goes away. I drive it home and 15-20 minutes into the ride it appears again.
The rear was re-built by a local gentleman here in NJ. Bridgewater, about 2 years ago. I believe this guy knew what he was doing. Glen was his name. NCRS judge with a shop full of Corvettes only.
It shifts nicely, I can spin the wheels when accelerating. No groan till it gets heated.
Will the bearing behave this way when it gets hot? There is no noise when coasting (engine off) and swerving left to right. Only when starting from a stop. One can argue it appears to be a bit worse when turning left but it is just as bad when moving forward.
I find it interesting that when I get to my destination 30 minutes away I think I need to call a tow truck to get home. Let the car sit and it goes away. I drive it home and 15-20 minutes into the ride it appears again.
The rear was re-built by a local gentleman here in NJ. Bridgewater, about 2 years ago. I believe this guy knew what he was doing. Glen was his name. NCRS judge with a shop full of Corvettes only.
It shifts nicely, I can spin the wheels when accelerating. No groan till it gets heated.
Thread Starter
Intermediate
Joined: Aug 2012
Posts: 28
Likes: 1
Can I rule out the rear if there is no sound when cruising or even when I cut engine. With the engine off the only things moving are the half shafts and tires and there is silence. (and I guess drive shaft is moving).
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Thread Starter
Intermediate
Joined: Aug 2012
Posts: 28
Likes: 1
no it is not touching. I am wondering if the caliper is getting hot and expanding...or something with the brakes. then again...
Melting Slicks
Joined: Nov 2006
Posts: 3,382
Likes: 1,801
From: Apple Valley, MN
I would not rule out the differential just yet. Not many people know how to properly rebuild these and the fact you said the noise was there before you had the other work done makes me suspicious. Have you checked the fluid level?