Build Build: Rusty Pumpkin Project 74' FJ40

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The patina on that 40 is leggit.
When I bought it the PO had used some spray paint to cover up all the spots where the old paint was coming off. A few hours of wet sanding and a polishing wheel did the trick.

This is the before
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Think I’ve tracked down the oil leaks on the t case

I’ve got some moisture behind the e brake
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And then a drip at the front output shaft
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I’ve got a new seal for the front output shaft and a new seal for the front pinion ring as that is looking moist too, on the way.

Also got brake parts on the way but that’s another update…
 
don't worry, scientists have been alerted. I have re-discovered the premarital soup where the first single cell organism was found. Turns out it was in the front diff of my FJ40 all along...

Drain bolt is still stuck but I used lubricant suction pump to pull this out....woof
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I have output shaft seals for the t-case and front pinion gear on the way so I fix my leaky t-case.

I also picked up the JT outfitters 3 bolt to 4 bolt brake master cylinder adapter and I'm working on updating the braking system. Once I have all the parts here I'll share the plan!

Hope everyone has a fun Sunday!
 
I replaced the front output shaft seal on the transfer case to hopefully rectify this ongoing leak...wasn't too challenging and went quicker than I expected. I purchased two seals just in case though.

I had some continuous dripping once the seal was removed so I ended up draining the t-case. Maybe mine was slightly overfilled so this may not be the case for you. I could have jacked up the front a little to keep the fluid to one side as well but I was happy to drain mine and just refill with fresh fluid.

here are the seals I bought. Mine is 74 and these fit great.
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here is the seal location that I replaced

Screenshot 2026-05-04 at 1.53.48 PM.webp



I dropped the drive shaft and then got to work on removing the companion flange
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I was expecting to need a puller but when I put mine on the flange basically came right off. I put the truck in 4H and pulled the e-brake on to remove the 27mm nut. Once the companion flange was removed it revealed a seal that has seen better days.
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I used a seal puller and the old seal came out without much fuss at all. I drained the t-case and then cleaned this up nicely in prep for the new seal. Here. you can see there was quite a bit of gear oil running out so I'm pretty sure my t-case was overfilled. I did top off the t-case in prep for driving about 200 miles over the weekend so this could be it.
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continued....
 
here is the new seal
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missed getting a pic of the seal installed but you'll want something to help press it in and allow you to help evenly put this thing into place. I cleaned up the companion flange and used 1000 grit sand paper to clean up the shaft and smooth things out where the flange contacts the inner seal. The groove looks worse than it is but it's still not great and I imagine this could lead to a seal wearing prematurely as these two surfaces should be smooth and polished. Might be time for a new flange...
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Refilled the t-case and was careful to not overfill this time...

Didn't have a chance to drive it yet but hopefully this is the fix! :-)
 
don't worry, scientists have been alerted. I have re-discovered the premarital soup where the first single cell organism was found. Turns out it was in the front diff of my FJ40 all along...

I just gotta say..."premarital soup" either sounds like the best thing ever, or the worst. Can't decide...
 
As I scrolled down and saw that pitted flange all cleaned up, I said to myself oh no I hope he doesn't use that. I had one similar that I cleaned up to no avail.
Had to replace the flange after a leak.
And yes, a light coating of rtv around the outside of the seal also
 
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