Modify the right side case to fit the flipped crown wheel. Clearance for the differential carrier, crown wheel and crown wheel bolts should be checked by progressively fitting each part to the right side case. It's finished appearance should be similar to the left side case when complete.
Subarugears machined case ..........................................Customer hand ground and finished case
If you are using the transmission in it's 4WD state then that is the extent of your case modifications. Move on to fitting the Subarugears ring and pinion and differential set up.
Check out the video of how to clearance the case :
Shortening the 4WD case to a 2WD case for Beetles, Kombis, Vanagons.
As we are only using the 2WD part of the transmission, the casing can be shortened to 565mm length (plus 80mm length of shifter support tube that is placed over the top of the torsion bar).
This should be performed on the later style center differential housings from 1999 onwards ( 8 bolt or TY754/755/758)
Earlier style center housings (4 bolt TY752) are difficult to shorten effectively. These are identified by their square panel on top of the center differential case. Newer center differential casings are interchangeable with older side casings.
Mark out the cut line
9cm (3 1/2 inches) from the end with the cast bosses for the mounts. Do not mark all the way around - leave the base of the shift rod support tube unmarked and uncut.
Carefully mark above and below the shift rod support tube. The castings are left thin there so are easy to cut through.
Be very careful - there is a bolt just to the right of this round plate (gearshift interlock) that holds a ball and spring in place. Do not grind off the bolt. Do not grind down the flat mounting surface for this bolt or the tension that the ball and spring places on the interlock will be incorrect.
Rough cut complete....Back................................Right hand side.............................................Left Hand Side
Note there are three holes to fill :
1) Large hole with Subaplug
2) Hole on inside of shifter support shaft, filled with TIG weld, threaded plug, Devcon or Silicon
3)Weird shaped hole on right hand side, filled with TIG weld, Devcon or Silicon
After some finish grinding and flap disc work plus holes filled with Subaplug, threaded plug, TIG weld.
Complete shortened Subaru transmission casing
Check out the video of how to shorten the casing :