Rear End Problem ?
Senior User
Joined: Mar 2004
Posts: 169
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From: hallville
03redstx how did you make out.The reason I asked of course is becaUSE MINE IS DOING IT TOO AND MINE IS A 4X4.(2002 SC4X4 7700).I had my buddy look under and he said it would load up and release in the diff .So it looked like.I'm wondering if it's just a possi trac problem where the clutches slip a bit or something.Because it's a slip and a clunk at the same time.Not just a clunk.A light sounding clunk ,like from aluminum or somthing.I have a steel driveshaft but most would have a aluminum.Mine also goes away sometimes.My buddy (a mechanic) told me it's the diff fluid and possi additive breaking down.The clutches aren't slipping under light load.Only under moderate load.then they just slip and hence the clunk.Change fluid and possi additive and should fix itself.....I'll wait for your response before I buy $100.00 of sythetic 75w140 diff oil and two bottles of posi lube.What do ya think.
Tuned
Joined: Nov 2005
Posts: 444
Likes: 2
Well, it is hard to tell whether it is completely fixed. I picked it up this am, and the ball joints were definitely toast, so it drives a million times better, but it was so windy today, it is hard to tell whether the stoplight shudder is completely gone. I'll drive it tomorrow a little more and let you know. My rear diff is synthetic already, and I have freighted this truck probably more than I should have, but I don't abuse it. The only fluid that I haven't changed to synthetic is the rear axle. Worth every penny no matter what. I treat my truck like it has the 7700 payload package, and it likes it. Definitive proof tomorrow whether the driveshaft lube works.
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