Toyota 4WD Transmission Strength Comparo:
From Weakest ---> Strongest:
L-series (1979-1983) --> G52 (1984) --> G52 & rare-G58 (1985-1988 Carb) --> W-series (1985-1995 EFI) --> R-series (1986-1987 Turbo; 1988-2005+ V6)
I've not seen the inside of the new 6 Speed Taco transmission, so excluding that, the R-series transmisison is the strongest 4WD Transmission Toyota has ever made.
Regards,
BigMike