The 700R4 transmissions can be identified by the oil-pan having a rectangular shape being longer front-to-rear than side-to-side and held to the transmission by 16 bolts: three bolts front and rear; five bolts left and right sides.
The original version of the transmission was fully hydraulic and had a 27-spline input shaft which was a common failure point. In 1984, some of the weaker 700R4s parts were re-designed for use behind Chevrolet small block V8s received a 30-spline input shaft which used a different torque converter than its 2.8 V6 and 2.2 L4 power-plants. Between 1984-1987, internal components, from the ring gear to the oil pump housing, were updated, ending with the auxiliary valve body (for 700s manufactured after October 1986).
Upgrade kits were developed to eliminate some of the shifting quirks and reasons for premature failures. These kits were instrumental in improving the lifespan and allowing the transmission to perform better and last longer. This was a nice addition considering the quantity of these units on the road.
By 1992 the transmission was upgraded to use a computer control system to match the new cars technology. For the most part, many of the internal components could be swapped between the 1992 models and pre ’92 models by an experienced technician.
In 1995, the 4L60E received a PWM-controlled lockup converter. 1994 fullsize chevy trucks have been seen with PWM; Late year 1994s are equipped with PWM (referred to as model year 1995). Only for sure way to know is pull the transmission out and PWM will be stamped into the front of the transmission below the input shaft.
In 1999, GM introduced a redesigned 4l60E transmission case that incorporated a bolt-on bell-housing and an 6 bolt tail-housing. The 1999 and up model 4l60Es are referred to late-model 4L60Es, and the 1993-1998 are referred to as the early-model 4L60E. Both transmissions are essentially the same internally with only minor modifications. The Early-model and Late-model 4L60Es are not interchangeable.
Only a specialist should be working on transmissions, it is easy to see how much information a transmission mechanic has to have in mind and available on demand. Our transmissions are prepared by the best transmission technicians in the country and with all current updates and redesigned parts to exact the best out of this unit. For more information and pricing on transmissions call GotTransmissions.com @ 866-320-1182.