backsides' twerk'n
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Lead Driver
Joined: Sep 2010
Posts: 7,793
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backsides' twerk'n
lol....anyway, how can youm tell if theres not enough/too much friction modifier in the rear diff? Mine, even under a slight ndogleg left/right, on the freeway, seems to wanna "hop" abit. Not sure if its just the road, and the road being a poorly poured surface(lots a traffic here in ca), tires suck, or in fact the diff needs some attention...thanks 
Hotshot
Joined: Jan 2011
Posts: 18,849
Likes: 179
From: Puget Sound
Without knowing what condition your differential fluid is in, it sounds like it's worth a try. This would be step one, and hopefully it can nail it. I tried all kinds of things, but I eventually had to replace the clutch pack in the rear.
Lead Driver
Joined: Mar 2013
Posts: 7,460
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From: Kent Station, WA
Did you recently change the rear diff fluid? If so what was all used? Some gear oils come with the friction modifiers already like royal purple and mobil so it isn't neccessary to add more.
Cargo Master
Joined: Nov 2005
Posts: 2,768
Likes: 58
From: East Tawas, MI
Welcome to guzzle's Rear Differential Maintenance Web Page
Hey,
I just installed a used 60K mile rear axle assy complete. 3.73 Limited slip.
It was shipped dry.
I followed guzzles instructions to the letter but used Mobile 1 synthetic 75-140w with the LSD modifier already integrated into the fluid.
I have absolutely no chatter, no vibration and it locks up on demand instantly.
Very happy with it.
My two bits.
Denny
Hey,
I just installed a used 60K mile rear axle assy complete. 3.73 Limited slip.
It was shipped dry.
I followed guzzles instructions to the letter but used Mobile 1 synthetic 75-140w with the LSD modifier already integrated into the fluid.
I have absolutely no chatter, no vibration and it locks up on demand instantly.
Very happy with it.
My two bits.
Denny
Lead Driver
Joined: Sep 2005
Posts: 9,399
Likes: 188
From: Norco,CA
Mobil 1 is good but some still have to put modifier in. The way I tested it was go do some figure 8's in a large parking lot. That works all the fluid and modifier into the clutch pack. If it still hops add more. I think it comes in 4 oz packs if I remember correctly.
Posting Guru
Joined: Oct 2008
Posts: 1,080
Likes: 10
It shouldn't "Hop" at all. That's not a positive observation.
I would take the cover off and look for signs of chipped or broke gears pinion, ring, and spider gears prior to a catastrophic failure first.
Without the modifier, more noticeable to the operator is dragging or having to fight the wheel in a corner or long radius similar to 4x4 on a dry road.
If everything looks okay and you're satisfied, move forward and inspect universal, slip yoke, and pinion play, Wheel Balance, etc .
Close it up and ensure the proper amount of fluid and modifier is replenished.
I would take the cover off and look for signs of chipped or broke gears pinion, ring, and spider gears prior to a catastrophic failure first.
Without the modifier, more noticeable to the operator is dragging or having to fight the wheel in a corner or long radius similar to 4x4 on a dry road.
If everything looks okay and you're satisfied, move forward and inspect universal, slip yoke, and pinion play, Wheel Balance, etc .
Close it up and ensure the proper amount of fluid and modifier is replenished.
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Lead Driver
Joined: Sep 2010
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im an idiot on how to "multi-post" all your responses, but really appreciate the input.
The axle was installed 1-1/2yrs ago. New fluid then. Seems, which i found a bottle, is valvoline syn 75w-140 installed, with modifier. Approx 55k on the fluid. The gears looked great, compared to the axle i replaced it with.
So when doing donuts in a parking lot, if the axle needed more modifier, the thing should act up then? If so, then im leaning more to tires and road condition...
The axle was installed 1-1/2yrs ago. New fluid then. Seems, which i found a bottle, is valvoline syn 75w-140 installed, with modifier. Approx 55k on the fluid. The gears looked great, compared to the axle i replaced it with.
So when doing donuts in a parking lot, if the axle needed more modifier, the thing should act up then? If so, then im leaning more to tires and road condition...
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Lead Driver
Joined: Sep 2005
Posts: 9,399
Likes: 188
From: Norco,CA
The Donuts just let it all work in. Really if it still slides a tire like don't slipped one or the other then it needs more modifier. That's what I've been told and done it myself. I have LS and love it. Mobil one comes with modifier but if you talk to them they will tell you to add if necessary. So I would guess your brand would be the same.
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