97 & 98 4L60E differences/interchangable?

The vehicle I'm looking at here isnt an Fbod this time, but still a 4L60E. Its a 97 S10 Blazer 4wd, 4.3. The rebuilders list the transmissions to order as 95-97 and 98-99, so some interchangability issue is present between 97-98. What is it? Whats it take to adapt this 98 into my 97? In my ASTG manuals I notice bell diffs, but that cant be all the difference in bolt up is it? Does 98 still use the TCC/PWM solonoid? Someone said a solonoid change is all needed but I cannot figure it out.
jay

The breaks are 93 94 95/6 97up. The only differences in interchange after 97' is the input shaft diameter that I know of.