Well, before I sent my transfer case off to Jacks for a rebuild i was running some 85w90 gear oil in it and i was getting yellow flakes coming out of the T case EVERY time I changed the oil (multiple times mostly less than 3k between changes). I got my t case back all nice and rebuilt, after driving about 120 miles I still have a very odd feeling in the car like a bearing is going out/ vibration whenever im going 50+ with a moderate to heavy load. The oil i drained yesterday also had yellow flakes in it from JUST 120miles. The thing is the T case calls for a Gl-5 oil yet there is a brass "stabilizer" ring for the drive shaft yoke to keep it centered. I was under the influence that you dont use a GL-5 fluid in the trans because it's additive package is bad for yellow metals. Would it be beneficial to just use a GL4 fluid in the t case? I really want to find what is causing my wear and vibration/ bearing failure feeling in the car as i dont think its safe to go past 45mph in its current position. Im running a 6 speed DS in my 5 speed AWD swap. The front u-joint is good, but the second one down the shaft is relatively stiff. Could this be causing the front yoke to wobble around and damage the brass shaft?