Stupid Diff Fluid Question

Mike67

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So I had a new Dr Diff power-lok & new Motive Gear set installed a while back. Putbabout 10-15 mi on it but would howl/clunk unloaded otherwise it was fine. Backlash IIRC was .022" +/-. Sent it back and that was corrected but now I had a vibration that was pretty severe & wasnt there before, so much so I barely got it out of the drive. Checked U joints, axle flanges, rotor hat, TC/flex plate etc looking for the cause.
Decided to pull the cover and make sure the pinion wasn't hitting the carrier everything looked good. Now I have a Moser cover and the bottom of the fill hole is C/L of the axle tube, which I used to gauge the ammount of fluid I had in it. I've always filled until fluid runs out of the hole.
Now here is the dumb question, can over filling a diff cause a vibration or shudder? The reason I ask I decided to look at my FSM & it showed that a Dana needed 5.5 pts! That is 2.75 qts. I drained out about 6.5 qts! Checked everything & it looked good, put the cover on & no more vibration or shudder...
FYI the moser cover doesn't add any extra capacity.
7112 - Performance Cover - Dana 60 - Moser Engineering
I'm at a total loss!
 

pnora

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I can not see how the extra fluid would cause any vibrations.
 

PlymCrazy

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Agreed, I can’t see how the fluid level and a vibration would be related either. Interested to know myself if it is a common phenomenon.
 

padam

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I have bent my pinion snubber to the point where it hits the yoke. This was an 8 3/4, not sure if it’s possible on a Dana
 

snakeoil24

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The extra lube should buffer the sound of vibration, over filling 1 qt is not likely to cause an issue. The 8 3/4 is more likely to have issues then a dana ever will, since the Dana is a much heavier Housing.
 

Mike67

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Ya, Im just grasping at straws on this. Everything I think would be a logical explanation had already been verified as working correctly. Trying to figure out what changed.
 
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