rear end question

[j_cifelli]

So I was driving down the road after recently having a 4 inch lift installed And the truck started to howl when you let off the gas And wind when accelerating hard. I got under the truck and wiggled the rear drive shaft where it meets the pumpkin and it has some wiggle room to it. So im thinking I need a new pinion bearing. How bad of a job is this? Any input is appreciated
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[LONGHAIR]

If the pinion is loose enough to wiggle it by hand, it is already destroyed. Simply changing the outer pinion bearing will not fix anything. The pinion has already moved enough to change the contact pattern of the gear teeth, and it is very likely that enough metal particles have gone through all of the bearings.
The whine you heard were the death bells.....
Complete rebuild required (or replace the whole axle)

[76k10]

Not so fast... Are you sure it's not just a bad U-Joint?

[j_cifelli]

I did further investigation and the big nut at the yoke that holds the spline that goes into the pumpkin came loose. I put a torque wrench on it and it turned about two full turns. Don't understand why it came lose to begin with though...
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[76k10]

Originally Posted by j_cifelli

I did further investigation and the big nut at the yoke that holds the spline that goes into the pumpkin came loose. I put a torque wrench on it and it turned about two full turns. Don't understand why it came lose to begin with though...
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Did that fix it?

[j_cifelli]

The wiggle and slop that was present went away but the sound actually got louder.... brought it to the rear end shop.... now im at the mercy of the mechanic and 80 an hour for labor:õ.... o I also jacked it up while the nut was tightened and the shaft was still out and when I turned the tires there was a clunk sound coming from the pumpkin.... why did that nut have to come loose.......
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[andrewmp6]

Only thing i can think of why it came loose is maybe who ever installed it last didn't torque it right and worked its way loose over time.

[Bigdav160]

The nut is self locking and shouldn't come loose. In fact I've never seen one "come loose" but have seen many that the pinion bearing preload was not set correctly and the pinion came loose.

I suspect somebody messed up.

[LONGHAIR]

Yeah, assuming that it had the correct nut, they do not "come loose". Depending upon the rear end in question, they have either a "crimped style" prevailing torque nut, or a "staked style" nut. These have a thin flange around the threads that gets driven into a groove that is cut into the pinion threads.
Neither of these will loosen on their own, but things can wear internally enough for the pinion to become loose with out the nut ever moving.

As you will soon find out from the mechanic, once the pinion "moves", it is toast. You cannot just tighten it back up. The incorrect wear has already happened. It will howl/whine, which is the sign of it's impending death.

It may be more cost effective to replace the entire rear end with a used one from the boneyard, but there is some work there too. You have to find one with the same gear ratio (or take this opportunity to change to a more desirable one?)
You also have to consider the brakes. The used ones may need rebuilt, or swapped for your originals.
And, you are not likely to get much of a warranty with used parts. If you do, it will be parts only, no labor.

[76k10]

I think it's better in the long run to just write the check for $1000 to have it rebuilt with an Eaton LSD. It may suck to write that big check initially, but then you have a stronger rear end with fresh seals and bearings versus another stock rear end that could be on its last leg.

[j_cifelli]

Yea maybe something gave inside the pumpkin and that made the nut apear to be lose the lift could not have caused it right? I only did 4 inches. Also I don't know what a eaton is what would I tell my mechanic ?
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[j_cifelli]

Bottom line should I pay for the rear end to be rebuit or order something else? If not rebuilt then order what? Also keeping in mind I want to put 35s on the truck
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[76k10]

Originally Posted by j_cifelli

Bottom line should I pay for the rear end to be rebuit or order something else? If not rebuilt then order what? Also keeping in mind I want to put 35s on the truck
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It depends. What do you do with the truck? If you just put around town never going off road or trying to go fast, the stock open carrier will serve you just fine.

However, if you put your truck in situations where you need increased traction and/or putting a lot of power to the ground then invest in one of these carriers.

http://www.summitracing.com/parts/et...-010/overview/

Then you will need complete bearing and seal kit. Like one of these.

http://www.summitracing.com/parts/rat-3005k/overview/

These parts are for a 12 bolt rear end, so you would be to be sure what rear end you have. If you want to change gear ratios this is a go time to do so. However, if you are 4wd that will require you to change the gear ratio in the front end.

There are a TON of options when it comes building a rear end so do your homework.

[Rubble]

Originally Posted by j_cifelli

Yea maybe something gave inside the pumpkin and that made the nut apear to be lose the lift could not have caused it right? I only did 4 inches. Also I don't know what a eaton is what would I tell my mechanic ?
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I highly doubt that your recent lift had anything to do with the diff going out. Maybe a u joint going out,but not diff. It's just happened at the same time...Like others said,the pinion nut shouldn't come loose!! There was some wear inside the diff to cause excessive play..
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[j_cifelli]

Its just going to be a around town truck not going to be out mudding with it or anything crazy. Just dont want to break another rear end again not a pleasant experience ya know haha. Its got the 8.5 10 bolt rear end currently. . I think it has 3.73 in the rear because its a 3 speed and I can only do 60 on the highway thats at about 2900 rpms at that point with 32 inch tires.
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