Does a 1991 gmc sonoma 4.3L v6 auto have 4L60 transmission?
No, a 1991 GMC Sonoma with the 4.3L V6 and automatic transmission almost certainly did *not* have a 4L60 transmission. The 4L60E (the "E" is important, denoting electronic control) wasn't widely used until the early to mid-1990s. 1991 Sonomas of that configuration likely used the TH700-R4 automatic transmission.