Front Output Shaft Castle Nut

Joined
Oct 14, 2021
Messages
7
Location
Kansas City
Hey all,

Trying to replace the front output seal on my 67 FJ40 and cannot seem to get this output shaft castle nut to budge. I built a steel jig to hold the flange from moving and then tried using a long breaker bar on the nut to break it loose (counter-clockwise/lefty-loosey). It had a cotter pin through it (removed) and it doesn't look like it is staked or has any of those metal tabs, but it doesn't seem to want to move at all.

I'm going to soak it in penetrating oil overnight, but I'm doubtful any oxidation is the issue.

Any other things I should be thinking of?

Thanks!

--Sean

fj40-front-output-shaft-castle-nut.jpg
 

mrboatman

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Oct 21, 2016
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Southern Nevada
I have used a electric impact wrench I should come loose pretty quick.
 
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Oct 14, 2021
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Turned out to be a TON of black RTV holding the castle nut (and everything) in place. The PO must have just coated the insides when they were replacing the seal.

Notes for others who might run into this in the future:
1) It is not a left-threaded nut so standard lefty-loosey will loosen it.
2) A 20V impact wrench will have zero impact if it is RTVd in place.
3) Build a jig with a 24" piece of flat bar with two holes in it that you can bolt into the flange holes. That flat bar, when rotated, will rest against the frame rails keeping the flange from rotating
4) Per #3, I chose to do this with the 4WD gear selector in 2H because I didn't want to put pressure on the splines/gears while unbolting the thing
5) Heat will help soften the RTV. I chose a heat gun rather than a small torch since the T-case is still on the truck and was recently filled with gear oil.
6) A LONG pipe (the longest you can find that will fit your ratchet handle) and slow, easy pressure down will break the RTV loose and loosen the castle nut. Mine was a 3.5 ft piece of pipe.

Hope that helps someone in the future! Now I have to figure out how to get the flange off the nosecone because I'm positive the PO put the same RTV on the splines which means it's going to be just a challenging to get the flange loose from the splines. Then I'll be picking off the RTV with a soft plastic pick so as not to damage the splines.

If anyone has tricks for getting the flange loose from the splines, would love to hear them.

--Sean
 

pb4ugo

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spay-lay-wi-theepi, Ohio
You're supposed to use sealant on the output/flange splines. I prefer non hardening. Someone may have used some sort of loctite on the threads. You could probably use a harmonic/steering wheel puller
 
Joined
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Messages
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You're supposed to use sealant on the output/flange splines. I prefer non hardening. Someone may have used some sort of loctite on the threads. You could probably use a harmonic/steering wheel puller
My puller worked to get it off and it wasn't too bad. I'll use Permatex on the splines when re-assembling.

What sucked was the PO just squirted black RTV all around the castle nut, basically just filling up the entire gap. So I had to dig out the castle nut and then apply a bunch of pressure to get it to break loose of the RTV. Still leaked. The new seal I have has a rubber "nose" on the inside where the old one didn't. Should help maintain a better, long-term seal.

Another question.

When I pulled the old seal, it was filled with grease. Looked like the PO packed it, like you would a bearing race. Is this seal supposed to have grease in it? Nothing I have read so far points to anyone filling the seal with grease.

To see what I mean, here's a pic of the old seal packed and the new seal.

Thanks!
--Sean

fj40-transfer-case-seal-old-and-new.jpg
 

mrboatman

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Oct 21, 2016
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Grease is put in a seal for lubrication during first start up. It is not a requirement and not needed on the front transferase nose cone seal. Just wipe some gear oil on the output flange when you slide it on so the seal is lubricated.
 
Joined
Jul 18, 2022
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Location
Liberty, Kentucky
You could have built a jig to hold the nut and just put the truck in 4 low and eased off the clutch and broke it loose. That amount of grease is not normal, a pea sized amount, or less, wiped inside the groove lip on the seal is all that's needed. Must wipe off excess after installing.
 
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