Input pinion shaft on rear 8.8 wont budge! | Ford Explorer Forums - Serious Explorations

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Input pinion shaft on rear 8.8 wont budge!

Wrath

PackRatt
Elite Explorer
Joined
March 9, 2018
Messages
81
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64
Location
In the sticks!
City, State
Shingle Springs, CA
Year, Model & Trim Level
98 Sport, 5spd 4.OHV
Callsign
Pack Ratt
Hey everyone, me again. I'm in the rear diff of my limited to replace bearings and a bad ring gear. The new ring gear comes with its own pinion and shaft, so I'll have to set the depth and all that biz. The trouble I'm having now is getting the old pinion shaft out. I've got everything else out of the housing and reassembled the diff with new ring gear and tone ring, and my bearings are ready to go. I don't see anything like a locking bolt for it, and everything I've seen online indicates a couple taps on the flange nut is enough to kick it loose, but no joy. Any tricks to this?
20220622_185601.jpg
 



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Air hammer
 






Air hammer
Thought that as well, but I only have a hammer drill that doesn't have an option for hammer only. But if there's no pin or bolt or clip then I'll keep wailing on it until it pops.
 






20220620_204503.jpg

Obligatory damaged parts shot. Note also the mashed teeth on the speed sensor ring.
 






Does it spin easily or did the bearing weld itself?
 






That hurts to see, breaking teeth off of the ring gear is hard. I wonder what went wrong, low gear oil or too dirty/old(heat) etc?

The debris beat up the tone ring, but I don't think much could get behind the pinion gear to jamb between the shaft and housing etc. I'd keep beating on the old pinion nut(tighten it on by using all its threads). How does it feel as it's spun, any roughness, possibly debris in the bearings in there?
 






One thing I'd try would be using steel wire to wrap around the pinion, if the teeth are chewed, might be able get a wire to hold. Use a pipe or bar to tighten against the face of the housing, then beat on it. I figure it's like trying to remove a ball joint that's rusted into place. A hammer or press alone doesn't always do the job but using both together does.
 






I have done over 20 8.8 rears and it is common to have to beat the pinions out. Just smack it with a BFH and it'll come out.
 






I have done over 20 8.8 rears and it is common to have to beat the pinions out. Just smack it with a BFH and it'll come out.

BFH yes, the bigger the better. It takes much less effort to knock one out with an 8lbs sledge versus a simple hammer, and the 3lb baby sledge should be the first attempt.

I use a baby sledge on lower BJ's and TRE's, to pop those out. But if it doesn't let go with the first two or three whacks, I stop, and then go find the real sledge hammer. That 8lbs will work much easier, if there is room to swing it. You don't have to put as much effort into the swing of the heavier hammers, the weight does most of the work.
 






Does it spin easily or did the bearing weld itself?
Spins freely.

That hurts to see, breaking teeth off of the ring gear is hard. I wonder what went wrong, low gear oil or too dirty/old(heat) etc?

The debris beat up the tone ring, but I don't think much could get behind the pinion gear to jamb between the shaft and housing etc. I'd keep beating on the old pinion nut(tighten it on by using all its threads). How does it feel as it's spun, any roughness, possibly debris in the bearings in there?
It apparently happened prior to me owning the truck. There was no sign of debris when I opened the diff, and evidence that I wasn't the first one in. Previous owner never mentioned it, said he hadn't been into the diff. From the receipts in the truck it seems I'm at least the third, if not the fourth owner.

I have done over 20 8.8 rears and it is common to have to beat the pinions out. Just smack it with a BFH and it'll come out.
That's a relief to hear actually. I thought something was wrong because everything I had seen indicated a somewhat easy removal.

BFH yes, the bigger the better. It takes much less effort to knock one out with an 8lbs sledge versus a simple hammer, and the 3lb baby sledge should be the first attempt.

I use a baby sledge on lower BJ's and TRE's, to pop those out. But if it doesn't let go with the first two or three whacks, I stop, and then go find the real sledge hammer. That 8lbs will work much easier, if there is room to swing it. You don't have to put as much effort into the swing of the heavier hammers, the weight does most of the work.
Sounds like the plan then. I'll be back out there beating on it in a bit.

Thanks all!
 






A air hammer will rattle it out easy and you won't hit the Diff case with your hammer
 






Well call me the tooth fairy cuz I just found those missing teeth! Where, you ask? In between the input shaft inner and outer bearings, up in the nose of the diff housing!

20220623_183503.jpg
 






Oh, and yes I finally got this little turd out of the diff. See that groove around the middle of the shaft? I think one or more of these teeth were rubbing on the shaft inside the housing. Note also the totally mashed flange nut.

20220623_202543.jpg
 












So the teeth were acting like a lock ring I bet. Awesome
Pretty much, yeah. Taking measurements and notes, ordered another inner bearing to grind to slip fit and use as a setup.
 






Related: gelatinous/tarry goo in the axle tubes. Didn't want it nor its contained debris mingling with my new juice. After about an hour of scraping with a metal rod (tube only, not the bearing seats!) decided to do this the smart way. Old rotary wire brush and the long flexible shank of a broken installer bit, some drill to fit and JB Weld later, and I have an axle tube brush!

20220624_001631.jpg 20220624_010800.jpg
 






Am I trippin or did these cheeky dickwaffles JB this bearing race in? 😑

Edit: still not sure if it was or not. Had to hit it repeatedly with the torch, slide hammer wasn't working, so used the cup and shaft plus a 5lb sledge from inside the housing. Finally got it!

20220624_010330.jpg
 






That last photo looks like the before picture before the 2 races were removed.
 






That last photo looks like the before picture before the 2 races were removed.
It is. Posted before I successfully removed the races.
 



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Well done, hard but satisfying I'm sure.
 






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