4.16 Transfer Case        
(a.k.a. Rocklobster)
An inevitable part of any Samurai buildup seems to be lower transfer case gears. There are a couple of options available for this, a babylobster (stock 410 transfer case), rocklobster (combination of an 410 and a newer transfer case), or the GRSII (custom cut gearset - expensive). We chose to go for the rocklobster. This would give us an 76% lower low-range.
If you drive a Samurai or 413 it will give you an even lower (88%) low-range and a 12% lower high-range.

Samurai/413 Tcase
Shown here are the internals of the 413/Samurai transfer case:
(A) Input Shaft
(B) Counter Gear
(C) Output shaft with High Output Gear
Here are the gears  for a 1984 SJ410 transfer case.
shown from left to right
High Output Gear (F) 
Counter Gear (E)
Input Shaft (D)
Since our own car is an 85 410, we just used our own and bought an additional 413 T-case

SJ410 Tcase gears from '84 and later models

Both gearsets - 413/SAM are A, B, C and 410 is D, E, F:

In the end you want to have the gears assembled in your own transfer case (Yes, you can use a different type case but if you're running a samurai then you will need to swap the flanges/e-brake etc. over). We also re-used all of the bearings from the 413 transfer case.
Here's what you need to do:

1. Press the High Output gear off of the 413/sam output shaft (C) and press on the 410 High Output Gear (F).

2. Now the most technical part (this requires a quality machine shop). You need to take the larger 413 gear off by using a lathe and cut of the large 410 gear and take out the centre then press the big 410 gear on the stumb left on the axle and weld it . (see diagram underneeth)

3. Put the transfer case back together using the 410 input shaft (D), the new welded gear from step 3 and the413/sam output shaft (C) with the 410 high output gear on it.

4. When putting it back together you can remove one of the bearings in the shift-fork mechanism so that you can get the 2-low option (see the write-up on off-road.com here).

416 tandwiel.jpg (15002 bytes)  dessin_gear_nl.JPG (25243 bytes)  
Click the thumbs to see blow-ups from the diagram 
and finished gears of the "B-E" combination