Pinion nut came off... What now?

JieselDeep · **Posted:** Sat Dec 02, 2017 7:39 am

I had an odd noise come up today. Long story short, I pulled into Lowe's parking lot and researched the noise on lost and thought it was the CV joints on the front driveshaft.

No problem, I thought, I can have that off and still make it to my son's Christmas program without the use of 4wd... Got the shaft out and did a circle in the parking lot. Turns out the sounds wasn't coming from the front after all. 3/4 if the way through my circle, the rear driveshaft let loose. Pinion nut had worked it's way off. Rear wheels locked up at about three mph and I came to an abrupt stop.

What am I in for and how do I go about getting the truck able to be towed home? There was a guy coming out to his car that said he knew more about those differential than Chrysler, and said he used to build custom differential for off-road racing. He claimed that at one point a free years ago, his company made differentials for 90/100 of the fastest off-road trucks in the US. Stupid me, didn't get his number or name.

Anyhow, he described what would have happened if I had been doing highway speeds when this occurred and mentioned how the pinion shaft gets "sucked in" and locks the rear wheels. Well, soon after he left, I discovered that's what had happened to me. I'm hoping for no damage, but with failing light, and my kid's performance looming, I had to leave it there before I cracked the cover.

What are the odds I can just open it up and maybe jack up the rear end to give the gears some wiggle room as I pull against the nut on the pinion to get it to reseat? Am I dreaming?

Thanks in advance!
Jon

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WWDiesel · **Posted:** Sat Dec 02, 2017 12:15 pm

You are going to have to open it up and inspect for damage before making any real predictions! :roll:

If the pinion shaft went back into the carrier enough to lock it at 3 mph, chances are pinion teeth are damaged???

I would be real concerned as to "WHY" the pinion nut came off, it is a lock nut and is torqued to a substantial amount of torque to crush the "crush sleeve" to hold the correct preload on the pinion bearings.
Even if a pinion bearing gave up, the nut should have held in place! I have seen some very loose worn out noisey pinion bearings that were still allowing the vehicle to motivate, but the pinion nut never moved! :shock:

Sorry, keep us posted as to what you find...

WolverineFW · **Posted:** Sat Dec 02, 2017 12:23 pm

X2. I know the rear pinion nut on my F-350 is torqued to something like 600-650 ft lbs. The Chrysler rear end may not be that high, but it will be up there.

There is going to be some damage that is not going to be fixed in a parking lot if that came loose.

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tjkj2002 · **Posted:** Sat Dec 02, 2017 1:03 pm

WolverineFW wrote:

X2. I know the rear pinion nut on my F-350 is torqued to something like 600-650 ft lbs. The Chrysler rear end may not be that high, but it will be up there.

There is going to be some damage that is not going to be fixed in a parking lot if that came loose.

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Yeah not even close.

There is no torque value for those pinion nuts,you tighten the nut till you are in a set turning in-lbs reading on rotating the pinion(no axles installed).You will shear the pinion going that high.The Rockwell 5 ton axle has a pinion torque of 650lbs-ft and that is a 4.5" nut and a 3.5" diameter shaft.

WWDiesel · **Posted:** Sat Dec 02, 2017 1:57 pm

That's right, the pinion bearing lock nut torque is determined by measuring the turning resistance of the pinion shaft using an inch pound torque wrench which sets pinion bearings preload!

And some crush sleeves can be a major booger bear to get crushed enough to get the correct preload! Ask me how I know!!!! :shock:

tjkj2002 · **Posted:** Sat Dec 02, 2017 2:19 pm

WWDiesel wrote:

That's right, the pinion bearing lock nut torque is determined by measuring the turning resistance of the pinion shaft using an inch pound torque wrench which sets pinion bearings preload!

And some crush sleeves can be a major booger bear to get crushed enough to get the correct preload! Ask me how I know!!!! :shock:

M900 series 5 ton = 1" breaker bar with socket wedge up against frame rail and put truck in "D" or "R" depending on if your loosening or tightening.Let the truck do the work.

JieselDeep · **Posted:** Sat Dec 02, 2017 3:05 pm

Okay, what donor Vehicles can I find a rear axle from?

tjkj2002 · **Posted:** Sat Dec 02, 2017 3:38 pm

JieselDeep wrote:

Okay, what donor Vehicles can I find a rear axle from?

'02-'05 KJ are the only direct fit,granted you will have to swap out the drums from a '02 for your disc's.Also be aware that '02-'05 KJ's could have come with the very undesirable D35C.

WWDiesel · **Posted:** Sat Dec 02, 2017 3:48 pm

JieselDeep wrote:

Okay, what donor Vehicles can I find a rear axle from?

It may be cheaper to fix yours! Do you know what the damage is yet?

JieselDeep · **Posted:** Sat Dec 02, 2017 4:44 pm

WWDiesel wrote:

JieselDeep wrote:

Okay, what donor Vehicles can I find a rear axle from?

It may be cheaper to fix yours! Do you know what the damage is yet?

No, I'm about an hour away from getting there to take the cover off. I live in Hawaii, so shipping is a killer here!

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JieselDeep · **Posted:** Sat Dec 02, 2017 4:46 pm

JieselDeep wrote:

WWDiesel wrote:

JieselDeep wrote:

Okay, what donor Vehicles can I find a rear axle from?

It may be cheaper to fix yours! Do you know what the damage is yet?

No, I'm about an hour away from getting there to take the cover off. I live in Hawaii, so shipping is a killer here!

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I was looking up pinion and ring replacement kits last night and the cheapest I was seeing was around $400 I can buy a whole Parts car for $500 and that would have the benefit of giving me access to other things that I have been putting off fixing on the interior

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WWDiesel · **Posted:** Sat Dec 02, 2017 9:02 pm

I totally understand, but until you open it up and see what the actual damage is, it's all pure conjecture at this point!
You may be lucky and can get by with some minor replacement parts... :wink:

Need more info! :roll:

JieselDeep · **Posted:** Sat Dec 02, 2017 9:11 pm

Here's what I'm left with. Looks like I'll be finding some replacement parts at a minimum...

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JieselDeep · **Posted:** Sat Dec 02, 2017 9:15 pm

Can I pull the pinion shaft out the front if I remove the front bearing?

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WWDiesel · **Posted:** Sat Dec 02, 2017 9:49 pm

JieselDeep wrote:

Can I pull the pinion shaft out the front if I remove the front bearing?
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(Pictures) Thats UGLY!!! :shock:

To answer your question, No, the axles and the carrier must be totally removed first before you can remove the pinion shaft. It comes out through the back of the housing!
Got any idea yet as to why the pinion nut came loose???? :roll:

WolverineFW · **Posted:** Sat Dec 02, 2017 10:12 pm

tjkj2002 wrote:

WolverineFW wrote:

X2. I know the rear pinion nut on my F-350 is torqued to something like 600-650 ft lbs. The Chrysler rear end may not be that high, but it will be up there.

There is going to be some damage that is not going to be fixed in a parking lot if that came loose.

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Yeah not even close.

There is no torque value for those pinion nuts,you tighten the nut till you are in a set turning in-lbs reading on rotating the pinion(no axles installed).You will shear the pinion going that high.The Rockwell 5 ton axle has a pinion torque of 650lbs-ft and that is a 4.5" nut and a 3.5" diameter shaft.

I only stand partially corrected. Ford 10.5 inch is inch pounds. DANA 80 is 440-500 ft lbs. They do not use the same procedure. I have no idea what the Liberty rear end setup is.

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r1perk · **Posted:** Sat Dec 02, 2017 11:08 pm

I had to replace all of the bearings in mine. Too heavy towing work. It is fairly complicated. I would just swap it out for a good used one.

I had a nut come loose on a Ford E350. I was able to retighten the nut and drive on. Mostly because I didn't care what happen to the Ford.

WWDiesel · **Posted:** Sun Dec 03, 2017 11:55 am

r1perk wrote:

I had to replace all of the bearings in mine. Too heavy towing work. It is fairly complicated. I would just swap it out for a good used one.

I had a nut come loose on a Ford E350. I was able to retighten the nut and drive on. Mostly because I didn't care what happen to the Ford.

Pinion nuts should not just arbitrarily "come loose", if one does, it should be replaced with a new nut as they are lock nuts and are designed NOT to come loose or back off on their own! :roll:

Pinion nut came off... What now?

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