I just brought home a '88 suburban equipped with the 6.2L diesel and a 700r4 tranny. Something is not right with this tranny. Its shift characteristics keep changing. about 50% of the time it works perfectly fine, shifting as it should, but other times it either shifts at way too high rpms, or flat wont shift out of 2nd or 3rd gear. It got real bad when I had to kick it down out of OD...after it kicked down it would not go back into OD. I finally stopped and checked the fluid (perfect)...when I took back off it was working fine again. What should I check first...maybe a damaged or misadjusted TV cable? The tranny is full of fresh fluid.