I would re-shim the diffs and run it until there is a problem. The diffs in my MT2 which uses the same parts are holding up fine with an OS .18 and all I did to them was added the machined cross shaft and re-shimmed them.
The TR4 uses the same two speed spurs as the MT2 and I have had no problem with them either.

While you have it apart to shim the rear you might want to put new gears in it. They are not that expensive and it could possibly limit a headache later on. Other than the hardened cross shaft I don't think there really is another option besides the stock replacement gears.


rolland