Rear Diff Problem

[fly boy]

That rear ends seems beefy as hell. What # spline axles?

Do you drag race or beat the snot out of it daily?

Either way sorry to hear about your bad luck...

 

[rsjohnsn]

Thanks for the warranty info, I was beginning to worry a little. The axles are 35 spline and no I don't race or beat on it daily. I did figure out what has happened though. A while back I had backed the passenger tires of of the pavement and not wanting to put it in 4 wheel drive, I spun the tires until the passenger tires hit the pavement which is when I heard 4 loud popping sounds. After the popping sounds the truck ran fine and I wrote it off as the limited slip clutches engaging or disengaging. This is the only time I remember anything being odd. Anyway, the parts will be here today and I hopefully will be back on the road tonight. Oh yeah, when I said I didn't beat on her daily, I do occasionally spin the tires a time or two so this did undoubtly help cause the problem. By the way, does anybody have the torque settings for the carrier bolts and the main cap bolts? I found the torque for the main caps but they are different with one being 70ft lb and the other being 95ft lb.

Thanks
Scott

 

[fly boy]

One tire spinning and one on pavement... That does it to alot of rear ends.

I looked in the 6.0 bible and it doesn't contain any torque values for it. I would lock-tite it and go at least 95 ft lbs.

Might try calling the dealer. Sorry about your bad luck. You won't have to re-shim will ya?

 

[rsjohnsn]

Thanks for looking! I don't believe I have to re-shim since I didn't remove the pinion. I did put the shims back the way they came out and the back lash feels the same as before I took it apart. I guess we'll see what happens in about an hour. I do have everything back together with lock-tite and I torqued the bearing caps to 95ft lbs and the differential case bolts to 100ft lbs. All I am waiting on is for the rtv to dry on the cover before I apply the gear lube. I went ahead and installed new clutches in the differential while I had it apart even though the olds ones didn't look worn. Do I need to change the fluid after so many miles like you do with a ring & pinion swap or am I ok with not doing it? I probably will just to check everything and make sure nothing has worked loose.

Thanks
Scott

 

[rsjohnsn]

Ok, I got everything done. As I was letting the truck coast out of the driveway with a little turn to the left she made a loud popping sound again. Now the truck was in neutral so it wasn't under any load when this happened. I drove the truck afterwards and everything seemed fine. I am hoping and praying that it was everything meshing itself back together. What does everone else think? Should I be concerned?

Thanks
Scott

 

[Kleetus]

Just noise or was there any vibration or chatter felt when this occured? I can't think of any good reason you should ever hear popping noises from out back. Now it is possible that the clutches in the limited slip are dry and need to spin a bit to get some lube between them. There have been many TSBs over the years about adding more friction modifier to the lube to make the "slip-stick" noise go away. It's usually heard after long periods of highway use, then making a sharp turn. That is considered normal. I don't like the modifier as it makes the clutches wear faster and generally don't work as well.

Did this popping noise sound the same as it did before, or different? You might as well do a few full left and right turns with it to see what other sounds it might make.

 

[rsjohnsn]

This happened within the first few feet of the driveway. Everything was dry except for what was sitting in the axle grease. My driveway has a slight downhill slope and a minor turn to the left. As soon as I put it in neutral I turned the wheel and let off the brake. I immediately heard 2-3 loud popping sounds from the rear axle. I have since put about 25 miles on it and all seems fine even the tight left and right turns. I haven't felt any vibrations or heard anymore noise. I plan on changing the grease again Saturday so I will do a visible check on everything and see how she looks. I am hoping that it was the new clutches making the noise since they were dry.

Thanks
Scott

 

[Kleetus]

Hope so too for your sake! Maybe having one of those "clear gears" covers wouldn't be such a bad idea after all!

I really wish Ford would put a decent locker under the back of these things... the limited slip is a bad joke. I know the LS arrangement in the 450 and 550 is different, and a whole lot more robust. Cone type clutches handle much more abuse and ask for more, look at the Aurburn posi.. case in point.

 

[lvtitan]

i'm assuming your truck has been jacked up on jackstands or blocks for a while waiting for repairs.
the noises you heard could have been the suspension settlling back into place after being unloaded.

 

[rsjohnsn]

Ok, I just got back from putting around 1600 trouble free miles on the old girl so I am assuming everything is fine with the rearend. I have yet to pull the cover back off but I am going to change the fluid again this week so I will do a double take on everything. I hope you are correct LVTitan, I haven't heard anymore noises since.

Scott