Can I replace my 700R4 automatic tranny with a later model?
Yes. In fact, if your car was built prior to the 1987 model year, it’s probably a good idea (if you have the cash). In 1987 (and even on some of the very-late-1986 cars), a number of improvements were made to the 700R4, the most prominent of which was a change to the auxiliary valve body with the main body and stronger components. This valve body is a section added in conjunction with the full valve body that routes the fluid differently. Earlier versions simply have a cover plate in place of this valve body where a small amount of fluid reserve is kept for some operation. The newer model has an accumulator to regulate the engagement of the forward clutch so that the shift into “D” would be smoother. An abuse valve was added which, based on throttle position, would short circuit the accumulator and cause the “D” shift to occur faster (benefits apparent when rocking a car that’s stuck in snow or sand as it causes the clutch to engage faster to eliminate slippage and heat built-up). Thes
