The information below is interesting but not very useful since the problem does not seem to be ring gear size but spider gear or side gear weakness.
New Tundra differentials:
The V6 and 4.7 liter V8 get the differential with a 9 1/2 inch ring gear. This gear comes in two ratios depending on whether or not you order the towing package. This is the largest ring gear of any 1/2 ton full-size pickup truck. The 5.7 liter engine comes with an even larger 10.5 inch gear which is larger than most 3/4 ton pickup trucks.
FJ differentials:
An electronic locking rear differential with an eight-inch ring gear is available. The ring gear in the front differential of the 4x4 FJ Cruiser also measures eight inches.
Dana 44's - Nissan 8.5 inch