What is the transmission in 1991 suburban with overdrive?
A 1991 Chevrolet Suburban with overdrive likely has either a 4L60E or a TH700-R4 automatic transmission. The exact transmission would depend on the engine and trim level of the Suburban. The 4L60E was more common in later years of production, while the TH700-R4 was used earlier. To know for sure, you'd need to check the vehicle's identification number (VIN) or look at the transmission itself for identification markings.