Progress Report: My FZJ80 T-Case overhaul

[lc80fzj]

Picking up where I left off in my last post—here is the T-case after the removal.
It took me two full days to get it out, but it’s finally on the bench and the overhaul is now officially underway.

 

[lc80fzj]

Here is the transmission output shaft. As you can see, this was the source of the oil leak.
I already saw this coming, so I have a new oil seal and the O-ring for the retainer housing ready to go.

 

[lc80fzj]

Does anyone happen to know the exact torque spec for the five M8 bolts on the retainer?
Since the bolt heads are marked with two lines (Class 5T), I’m planning to torque them to 15.5 Nm.
Does that sound correct to you?

 

[lc80fzj]

Moving on to the split. I’ve included two photos of the case being disassembled.
Even with over 400,000 km on the odometer, the internals look surprisingly clean—wouldn’t you agree?

 

[lc80fzj]

However, I’ve run into a bit of a problem with the center case.
I followed Georg’s (Valley Hybrids) method from his YouTube video—soaking it in penetrating oil and attempting to drive it out with a punch—but it won't budge at all. It’s absolutely seized.

 

[lc80fzj]

Between other tasks, I’ve been repeatedly soaking it in penetrating oil and hitting it with a punch, but I wasn't getting anywhere.
I even tried pressing it out with a vise—using a socket as a receiver for the pin to pop into—while simultaneously heating it with a torch.
Despite struggling with it all day, the pin hasn't budged a single millimeter.

Since I’m dealing with an aluminum housing, I really don't want to get too reckless and risk cracking it. I would truly appreciate any advice or clever ideas on how to resolve this without causing permanent damage.

 

[lc80fzj]

Finally, I managed to get the transfer case shift lever pin out. These are the tools I used for the job, as shown.
My go-to is this "KURE Penetrating Freeze Lube." It has saved my life more times than I can count.

 

[lc80fzj]

After successfully removing the shift lever pin (which was exactly one week ago), I pushed through several more challenges to complete the TC rebuild and reinstallation three days ago.
From here, I’ll be sharing a digest of the custom solutions and the uphill battles I faced during the process.

 

[lc80fzj]

First, I fabricated a custom jig out of plywood to press the shaft out of the front extension housing.
Using this with a 20-ton press, I was able to remove the shaft safely.
I got the idea from Georg’s YouTube video where he uses a thick steel jig plate—I simply replicated the same functionality using plywood.

 

[lc80fzj]

Next, again inspired by Georg’s methods, I used a DIY transfer case stand. This allowed me to seat the input, idler, and output gears into the main case and made the subsequent case assembly much more manageable.

 

[lc80fzj]

These DIY wooden SSTs worked brilliantly, and the rebuild was progressing smoothly—until I made a major mistake during the final stages of assembly.
As I was closing the case, I noticed the shims sitting on the idler and output gear tapered bearing races seemed to be protruding slightly.
I mistakenly assumed they would settle into place once I bolted the case halves together.

Because I had already applied FIPG to the main case, I was anxious to get the rear extension housing torqued down before the sealant skinned over.
As I tightened the bolts, I heard a sickening "crack," and a visible hairline fracture appeared in the rear housing.

 

[lc80fzj]

Here is the condition of the idler and output gear shims immediately after I removed the cracked rear housing.

 

[Rdonahe]

Ugh. Sorry to see this. I recently re-geared and rebuilt my t-case and am grateful it all went back together without incident. I'm sure others with more experience here will weigh in on next best steps. Good luck!

 

[lc80fzj]

Fortunately, the rear extension housing is still in production. I was able to order a brand-new one through Toyota Parts Kyohan and get it installed.
Notably, the part number for the rear extension housing has been superseded from 36109-60020 to 36109-60061. I also noticed that the dust deflector has been updated to a different type compared to the original one.

 

[lc80fzj]

Reinstalling the assembled transfer case back onto the vehicle went relatively smoothly.
Aligning the height and side-to-side position is obvious, but I found the real key is to match the tilt of the protruding transmission output shaft with the angle of the transfer case input bore as accurately as possible before pushing it in.
I used several small wood scraps to fine-tune and hold that angle during the process.

 

[COS80]

This is a good thread.

 

[lc80fzj]

Ugh. Sorry to see this. I recently re-geared and rebuilt my t-case and am grateful it all went back together without incident. I'm sure others with more experience here will weigh in on next best steps. Good luck!

Have you changed both the high and low ranges of the transfer down gear?

 

[lc80fzj]

This is a good thread.

This is a good thread.

Thanks for checking it out.
Just paying it forward.

 

[Rdonahe]

Have you changed both the high and low ranges of the transfer down gear?

Yup. I did the underdrive high gear as well as the lower low range. I'm very happy with the result.

 

[lc80fzj]

Yup. I did the underdrive high gear as well as the lower low range. I'm very happy with the result.

When driving in high gear, or during normal driving on public roads, are you experiencing any gear-like noises that you haven't heard before?
I also replaced the high-range gear with an underdrive gear, but now when I press the accelerator, it makes a hissing sound that I've never heard before.