I found this site while I was trying to find tech info on the 4t40 and 4t45 transmissions. couple of guys were looking at 3.5's they are offered with the 4t45e's in the malibu maxx's , that 45e is the same as the one I have, which should mean that I can do the upper end swap on my 34 and use the malibu maxx flash.....
Any way I thought that it would be useful if your looking for a specific trans that came in a different model.

http://www.drivetrain.com/autotranscrossref.html


01 cav w/01 3400 gam gt 4t45e

Except that the Maxx uses the fly-by-wire, so the flash won't be compatible in that respect.

I don't think that anything uses the 4t40e after the J-body was ended. From what I gather Cobalts and everything else are now using the 4t45. Almost looks like the J-body was about the only thing using the 40.