ur longshaft bro i think.. ur grease in longshaft leak.(maybe)wah so many ppl having same problem with their evo during rainy day..... i dont think mind have prob with 4wd transfer box coz just replace the gearbox.... if gearbox prob it will make sound everytime and last time happens to me with the whinnningg sound during accelerate... any cifu can help to solve this matter....
r u use snow trans in the rains day...