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Help Diagnose Rear End Noise After Fluid Change

3350 Views 8 Replies 3 Participants Last post by  Danran
Hello and Howdy Do. I got a little issue For you. I took out drive shaft , replaced rear transmission seal, marked pinion nut, counted the threads then removed nut and changed the pinion seal, then I put it all back together just like it was. Took both rear tires off, drained the rear end and removed the brakes and hubs and axles, popped both seals then pulled both bearings. Replaced seals and wheel bearings with Timken, put new brake pins and grease on calipers and resurfaced disks. RTVed rear diff back on then let it sit over night. Filled with 2 bottles Castrol Syntrax Limited Slip 75w-90 and a 7 oz. bottle of limited slip gear oil add from Trans-x for anti frothing. ,This is a 7.5 rear with no T-Locker. Drove Car for about 5 miles threw 4 stop signs , turned around to come back and when I let off of the accelerator The rear of the car started talking like a bearing was dry , but as soon as i barely touch the gas pedal the sound goes away, put it in N and let it coast it'll talk , gas on it hard and it'll talk. Any Ideas?
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Jacked it up , noticed a wobble- n- knock right at the pinion to driveshaft during gear shift and free wheel n D . took loose the 4-12mm pinion nut and shaft are right on mark. Twist flange in hand about .50 inch both ways.
Bearing is allowing up n down lateral movement , I wonder if I could cam a bottle of 140w in her and fix it, maybe I ought to tighten down on 1'1/16' a little too. 238000 miles on stock oil LOL . Freakin wheel seal leak and now this. What would you do?
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You didn't get the pinion nut tight enough. You didn't cound the number of threads correctly or something. If you can move the pinion up and down then it's not tight. DO NOT DRIVE IT LIKE THIS.

I don't count threads when replacing the seal. I use a torque wrench and tighten the nut to about 150 foot pounds. You also need to use red Locktite on the nut when you put it back on or it will loosen up later and cause a lot of problems. You might notice oil seaping through the splines on the pinion around the nut later on if you didn't seal them. I use RTV sealant in the splines of the flange to keep oil from seaping out through the splines. This is a comon problem, especially when reusing a pinion nut.

You wasted your money on that oil and additive. Why did you use limited slip oil additive with a standard differential? All you needed was standard 80W90 gear oil.
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You Are Correct Sir. Bad thing was is I did drive it for about 12 miles and afterwards I tightened it up 1 more turn and that resulted in the rear tires locked up like e-brake was pulled . I put additive in because I thought It was what I was suppose to do , sincerely wrong :I

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Tried to send a pic on here of the differential, it's got tracks on it from the pinion now . This car was taken to "Bayou Customs" in Bastrop LA . The pumpkin is getting worked when the spring kit goes in . We're having blue reworked as a surprise graduation gift for my daughter . Took pic to BC yesterday and found out what you just said. Car was towed last night :)

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The "dry bearing" sound was probably just the rough surface of the freshly machined brake disks
The additive didn't hurt anything, just cost you some extra money.

Sorry to hear that it didn't survive. Sometimes a small job turns into a huge headache.
I thought that also Metalman till I jacked it up and put it in gear . Thanks

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Here's the mods list so far.
Bayou Custom has it now, I'm still having problems posting pics.
Body Kit
Paint and stripes
Seat delete
Harness bar or Roll Cage
Seat belt (4 pt. harness)
Radio , alarm
Lowering Springs
Wheels & tires
Timing chain
water pump
Under Drive Pully

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