Rear end noise

[twinB]

73 dart sport with 8 3/4 posi
A couple months back I removed my axels and pumpkin to replace the pumpkin gasket. After re installing the axels and pumpkin the car sat for a few months and now when driving I hear a growling noise whenever I’m off the gas and coasting. I’ve heard it could be the pinion bearing possibly the carrier bearings.

Is it common for something like this to just happen?
I’m worried the diff possibly moved when it was out but I’m not sure if that would cause the problem
I’m considering taking the diff and axels into a shop to replace the bearings on both but I figured I’d join this forum and seek some opinions

I’m no mechanic and im completely new to these cars any help is much appreciated
Thanks

 

[George Jets]

Adjustable Right side axle end play, did you get that adjusted right. (factory axle bearing application)

Did you install friction modifier along with regular 80/90 gear lube for the Clutch Style Sure-grip?

I would probably get the car up in the air, drop the drive shaft, and roll the pinion over by hand to see if you can feel any roughness in the bearings.

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Looks like you have the Green Style outer axle bearings, so the Diff Buttons are probably not used with these non-factory bearings, Sealed bearings.

Can roll the rear wheels over by hand to feel for roughness on the axle bearings too.

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[twinB]

Adjustable Right side axle end play, did you get that adjusted right. (factory axle bearing application)

Did you install friction modifier along with regular 80/90 gear lube for the Clutch Style Sure-grip?

I would probably get the car up in the air, drop the drive shaft, and roll the pinion over by hand to see if you can feel any roughness in the bearings.

_______________

Looks like you have the Green Style outer axle bearings, so the Diff Buttons are probably not used with these non-factory bearings, Sealed bearings.

Can roll the rear wheels over by hand to feel for roughness on the axle bearings too.

☆☆☆☆☆

hey George thanks for the reply and sorry for the late response I will jack the car up and inspect the pinion bearing and wheel bearings

Also the gear lube I put in was a 75/90 synthetic premix I hope that wasn’t a mistake

 

[George Jets]

Yeah that Synthetic is not the recommended gear oil for the Sure-grip Rear Ends.

Need the standard 80/90 gear oil with the friction modifier.

Dr. Diff recommends the Motorcraft friction modifier for the 8 3/4 Sure-grip rear ends.

Unfortunately you will have to pull the axles and gear chunk assembly to clean the synthetic gear lube out of your 8 3/4 housing.

☆☆☆☆☆

 

[Scody21]

As George said. It could be that the clutches in the diff could use replacing, as they are a wear item and it’s it not been done in 50 years, stuff gets old.

I’m running Red Line 75/90 synthetic with no added modifier but everything was clean, new bearings, clutches.