Where did you get the new taller gear and how much have you roughly spent on the rebuild not including tools?

 

Gears from Ashcroft transmissions in the UK

Taller gear set was about $650 from Ashcroft including HD cross pin
And probably at least another $400 for new bearings, o-rings, various parts, etc


Preview of next step


Measuring for the center diff preload

I strongly did not want to have to keep guessing on shim sizes so I found the official Land rover tool on eBay pretty cheap and bought it.

 

Ah forgot to post this part

Rear output housing installed

- Bearing race tapped in. Used a punch mostly, and a large socket for the last bit. Recessed 1mm, and when you torque the rear output housing bolts, the bearing track gets pushed in a little further
- Permatex anaerobic gasket maker. It's non-setting, and designed for close fitting machined parts. I feel a little nervous using it as its not as satisfying as a solid gloop of RTV, but it should be the right thing to use.
- Pressed rear flange bearing in, installed circlip
- Copper mallet to tap the rear output shaft and spacer into the bearing

 

Center diff shimming










original shim


new shim (3 shims stacked together)

 

For the input gear preload measurement, I mixed up the original shims from the two cases I tore down. One is 3.33mm, and the other is 3.55mm. I used the thinner one because if you use one too thick, you can't determine the preload. I measured zero end-float with the 3.33mm. Ideally I would redo the measurement with a thinner shim to make sure I don't over-preload.... but I don't want to do it again so I'm going to call this good.

 

Pretty much done!

Just have to order new switches (hi-low, neutral detect) as ALL of the ones off the case I bought were dead, including both diff lock switches. What are the odds?!

Also still trying to source a CDL shifter as I can't install the diff lock or hi-lo housing without those brackets.

Everything seems to function really well.

hi-lo shifts good
diff lock shifts good - however I had to use two sealing washers on the front switch, as it was sticking the mechanism occasionally
Gears turn smoothly
No end float or play in any of the three gears



I like this Permatex Anaerobic Gasket Maker. Here is what it looks like after its been cured. The stuff not in contact with mating faces stays gooey, so it won't gum up the internals like RTV surely would.







A little mod not in the manual.. I put gear oil RTV on both ends of the intermediate shaft. The only thing sealing those ends is an o-ring so I thought this was a nice free upgrade.












Not looking forward to installing this thing

 

I spent quite a bit of time experimenting with the diff lock engagement. I found one big concern...

- The front switch with only one washer was causing the dog clutch to get intermittently stuck open and/or locked, and even worse it would get "partially locked", i.e. diffs are locked, but the clutch was only ~25% engaged onto the front output shaft. There is no actual part number for the washer (??), and the manual says to "caution: ensure washer is same thickness as original." Well my case didn't have switches so I couldn't compare. The switches for the hi-low and neutral detect are the same design, so I used that washer. I ended up doubling up on washers for the front switch as you can see in this video:

Diff lock demonstration:

I'm still worried that if I engage diff lock, and the lamps go on, but the dog clutch is only partially engaged, leading to possible damage. There's no way to know if the diff lock is fully engaged without pulling the side cover and looking at the selector fork.

Paging anyone who can shed some light on that...

Some more notes...
- with diff lock switched on, you are not necessarily in diff lock yet. The lever only pulls the spring. So if the dog clutch isn't lined up with the output shaft, you won't be locked yet. I noticed that the center diff gears need to rotate a bit sometimes in order for the spring to find the teeth and move the fork over. In practical terms, you need to steer the car left or right a bit in order to work the center diff gears. Driving straight won't work like it does for the hi-low.

 

Just want to add to what was a very helpful thread for my T-Case upgrade.
Removing the rear circular plate and the gears behind it make for a VERY easy re-install. Goes right back in/on after mounting.
Cutting down some bolts for alignment mounting studs also worked very well.