My transfer case has a hernia. Any ideas?

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Joined
Nov 4, 2006
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I've got an '87 FJ60. Heard a really loud whining noise today coming from the transmission. I pulled over immediately, saw a shaft sticking out of the back of my transfer case. I shuddered, jacked up the back tire, and turned the rear drive shaft until I could push it back in. (felt like I was pushing in a hernia). Fab'd a new retainer clip from a washer and so far that is holding everything in place.

Here's my question: what made that thing pop out, other than the retaining bolt shearing? I did notice that my tc was full of oil (it was gushing out of the fill plug when I removed it), and the transmission oil was low. I have drained and filled everything and I'm wondering if an oil return tube will help me, or if I need to get a new transfer case. I am a starving college student so I'm hoping to get away with going the cheapest route possible (maybe not a good idea).

Anyone know if the oil return tube would be helpful or necessary?

Thank you kindly.
 
Sounds like you or the PO over tightened the bolt. Did the whining go away after you did your little fix? There is a thrust washer between the gear that rides on that shaft and the case that could have dropped out but if IRC there is a small key that helps hold it in. If that fell out I forsee a teardown in your future. Get a factory service manual if you end up doing that. If you need an oil return tube, I have one you can have for the cost of shipping
 
x2 on the thrust washer. I don't know how you tell it's still there or sitting in the bottom of your case.

The idle gear shaft has an o-ring on each end. If it pushed out far enough, you could have lost the seal at the transmission end, allowing oil to leak into the transfer from the transmission.

The classic failure for oil leaking from one into the other is the seal on the transmission output shaft. To replace the seal requires a tear down of the transfer case. The oil transfer tube is designed for use when the oil is leaking from the transfer case into the transmission. The transmission being higher in elevation, when it overfills the oil will flow back down to the transfer. When the oil is leaking from the transmission into the (lower) transfer the oil won't flow back up to the transmission unless you really overfill the transfer case. Check out the relative elevation between the transmission fill plug and the transfer fill plug the next time you're under your truck.
 
Yes, the idle gear shaft basically pushed all the way out. I did notice that the o-rings were still in place on the shaft when I pushed it back in. Is that the O ring that keeps the oil in the transmission?

There is no whining now when I drive it. If I understand you correctly though 2mbb, are you saying that there may still be a thrust washer loose and rolling around in my t case? That would mean a definite and immediate tear down for me.

Thanks a lot,

Josh
 
I had the same thing happen. You can do a partial tear down in the rig. It isn't too bad. That is what I would do.
 
There is an o-ring at each end of the idle gear shaft. I think the one installed on the front end seals between the transfer and the transmission. The one on the back end keeps oil from leaking out the back of the transfer.

There are also thrust washers installed on the shaft that push against the front and back halves of the transfer case. The front thrust washer is position 36222 onthe parts schematic belwo. As LCOwner said, there is a tab on the washer to keep it from spinning, but there is little else to hold it in place. I don't know how to tell if it's still installed.
transfer gear.webp
thrust washer.webp
 
I don't know how to tell if it's still installed.

Remove the PTO mount cover plate and do a visual...... plus check for excessive front to rear movement of the idler gear itself...... that tab on the thrust washer more times than not, keeps the washer in place......
 
Yup, if you pull the cover on the driver side of the case you can see the idler gears and shaft. The FSM shows this being done to check the wear of the thrust washers with a shim gauge between the case and the washer. You can check that the clearance is in spec and by doing so, determine wether the washers are still in place.
:cheers:
 
I had a feeling about that PTO cover plate. Thanks for pointing me in this direction! Also, thanks for copying the FSM diagrams!!

Josh
 
Can you change the o-ring at the rear/back/(outside the back end of the xfer) end of the idler gear shaft without complete disassembly? I think my o-ring there may be leaking.

As in, loosen the retaining bolt, pry out the idler shaft _*just*_ enough, dental pic off the o-ring, slide new one on, reinstall?

I don't want to pull the idler shaft out so much that the thrust washer falls off.

I read on here that it may be possible, but haven't heard of anyone actually doing it.
 
Can you change the o-ring at the rear/back/(outside the back end of the xfer) end of the idler gear shaft without complete disassembly? I think my o-ring there may be leaking.

As in, loosen the retaining bolt, pry out the idler shaft _*just*_ enough, dental pic off the o-ring, slide new one on, reinstall?

I don't want to pull the idler shaft out so much that the thrust washer falls off.

I read on here that it may be possible, but haven't heard of anyone actually doing it.

if the rear one is leaking the front must be as well......reseal the complete unit and be done with it....... or if you want to put this off to a later date? just clean up the area where the shaft sticks out the back really good and dope it up with some silicone sealant ......
 
Take this apart and do it right. If that shaft walks out again you will wreck all the internal parts in your case, and likely the case itself.

Or, if it leaks out all the oil, it will wreck the case too.

How worn does the shaft look? It's probably just time to rebuild the case. Not that bad of a job.
 

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