If you got the 4l60e thats got a removeable bellhosing from the newer body style (2000+ usually) then it should work, I have a 2001 4l60e behind my 06 5.3 and it works like it should with no problems. Since yours came with a 4.3 im thinking it may be the older style with non removeable bell housing, those can still be used with a flywheel spacer then a stand alone transmission controller. With it being a 1999 it could be eather one cause 2000(or early 1999) was the first year with the LS motor. I just transplanted a 5.3 and 4L60e into a 92 chevy c1500 that had a 4.3 /700r4
Last edited by montecarlo33; December 14th, 2012 at 04:48 PM.