Rear Diff Noise

[1967coronet]

Just for the heck of it, pull the rear wheels and brake drums.
Grab the axle ends and yank back and forth and up and down.
Should be zero movment.

 

[69'Net]

Had the same problem in a 70 Challenger. My started exactly as you described and then turned into a clunk at low speed acceleration while turning. The rear end needs to be checked for proper clearances on the pinion to differential case and axel shafts to differential side gear splines as well as differential side gear to pinion. Also check for worn thrust washers

Yeah it may come to that

 

[69'Net]

Just for the heck of it, pull the rear wheels and brake drums.
Grab the axle ends and yank back and forth and up and down.
Should be zero movment.

I check on that as well

 

[xho3]

Those old sure grips need the friction modifier regardless of what Lucas says. And old school 80W90 gear oil. New things are not necessarily better in our 50 plus year old cars.

Do you just need one 4 oz. bottle of the Ford Friction modifier in a Dana 60?

 

[Jerry Hall]

Do you just need one 4 oz. bottle of the Ford Friction modifier in a Dana 60?

Usually 1 bottle will do, but I had one car that actually took 2 bottles before it smoothed out, after about 30 minutes of tight figure 8's in a school parking lot.

 

[69'Net]

Sorry I've been busy and just now got back to working on the car. I'm still chasing the noise issue from the rear end and vibration which started all this. Let's focus on the noise first tho. After thinking about it, I hadn't really noticed the noise until I changed the rear u joint trying to fix my vibration issue. Since then I've tried three different u joints, different wheels and tires, different suregrip, had the driveline rebalanced. The driveline was out of balance but didn't change much. What I've noticed is, when I use the new U joints they're tight on the yoke side between c clips. The second suregrip is a 7260 combo, it was really tight, the noise was really loud and made noise all the time even driving straight. So I started swapping caps between all the u joints and put the thinnest clips in it. It got considerably quieter and less frequent. I dont get it. It's def not the rear gear. Just seems like it's a u joint fitment issue or something though. To describe the sound, it's an intermittent rubbing noise coming from the rear of the car when you turn. Still haven't ruled out aftermarket disk brakes or rear bearings.

 

[1STMP]

Is the pinion bearing tight
and free of movement?
Another question; does the
noise happen when you
make a turn in both
directions, or just one?

 

[69'Net]

Is the pinion bearing tight
and free of movement?
Another question; does the
noise happen when you
make a turn in both
directions, or just one?

Yes both suregrips are tight. I've tried two, same noise. The noise is both directions

 

[jeepthrills01]

Could also be a slight crack in the yoke..just a thought.

 

[1STMP]

Could also be a slight crack in the yoke..just a thought.

My thoughts also, as the
problem seems to be
narrowed down to the
pinion/yoke area.
Jeepthrills01?
Owned a few in my lifetime.
I love 4-wheeling....

 

[69'Net]

Could also be a slight crack in the yoke..just a thought.

When you say yoke, do you mean the slip yoke on the driveshaft? I tried two different rear gears

 

[jeepthrills01]

This

1STMP...yeah..I have had a few myself!

 

[69'Net]

This

View attachment 1629130
1STMP...yeah..I have had a few myself!

I've tried two different rear diffs. Probably not that. Probably just gonna start replacing parts arlt this point, starting with the bearings

 

[69'Net]

I checked the drive line angles today for the heck of it. I'm 1.1 deg down at trans side and .3 deg up at the rear yoke with the tremec angle finder. I'm thinking I need to shim the rear?