I had a similar problem with my 86 CJ, T5, D300. I couldn't tell if the noise was coming from the T-case or the tranny though it seemed to emanate from the T-case shifter. I checked u joints and found a bad one in the rear Drive shaft. after fixing it I still had the noise but not quite as bad. I figured the transmission was on borrowed time. Then I installed a CV driveshaft with proper angles and VIOLA! the noise disappeared and has not returned. Apparently the driveshaft vibrations were to blame combined with a T-5 and D300 combo that has 150k miles on them. FYI I have a SOA lift of about 5 1/2". All is good now. <img src="/forums/images/graemlins/cheers.gif" alt="" />