Well, no help from my previous post on the 1870 code and a valve body "fix." Oh, well.
Does anyone know if there is any difference in the 4T60E when paired with the supercharged 3800? Any differences in componants or anything than when paired to the naturally aspirated 3800? If I am going to rebuild this tranny, any suggestions to beef it up for greater longevity? I do pull a light motorcycle trailer on occasion with the 96 Bonnie. Thanks.

There is an HD version of the 4T60E... I think the major differences are a beefier differential and housing, and maybe some different clutches. My memory is escaping me right now. But it'* called the 4T60E-HD and was mated to the Series 2 L67 in 1996 and the Series 1 L67 from 93-95 or something like that. In 97 the L36 was mated to a regular 4T60E, but the L67 got the 4T65E-HD. From '98 through 2005 everything got the 4T65E (L36) or 4T65E-HD (L67). So basically if you're looking for a 4T60E-HD you'll want one out of a '96 or prior SSEi or supercharged SLE/SSE.

Someone please correct everything wrong with what I just typed.