700 Deluxe

Here's a tip we learned: while building a 700-R4, the pump seals must be "sized" before installation, otherwise they may tear upon insertion, causing an unseen leak. If you're doing this at home and don't want to buy the special sizing tools, the reverse input clutch housing and drum assembly can be used before it is installed.

Likewise, the input shaft seals need to be sized. Again, if you don't have the sizing tool on hand, the stator half of the pump can be used before the pump is assembled. Attention to these kinds of details can prevent problems down the road.

With the pump assembled, all that remained was to place its gasket into the case, followed by the pump itself (a little persuasion may be needed because of the pump's large O-ring). Later pumps have a small ridge to hold the pump body bushing in place--units without this ridge can slip loose, spilling fluid and laying down a nice smoke screen. (Don't ask how we know about this, just use the later pump.)

Earlier, we mentioned the 2-4 servo, which activates the 2-4 band assembly. The beefier pieces on the left, known as the Corvette servo, should replace the earlier, less effective pieces on the right.

The assembly is composed of the servos as well as the second and fourth apply pistons. The pistons push on the band to stop the drum. The improved servos give the pistons more force, making band application more positive and preventing slippage.

We also mentioned the 1-2 and 3-4 accumulator assemblies. Here, the 3-4 accumulator piston pin was fitted with a spacer rather than the spring it came with from the factory. Again, this will eliminate the "shock-absorbing" feature of this system, making shifts quicker and firmer. The 1-2 assembly, not shown, is similarly modified with two spacers.

Fluid pressure is also increased by a trio of strategically drilled holes in the separator plate (arrows). The case side gasket is on, so the plate can be set into place.

Before installing the valve body, we went over B&M's modifications, starting with the line bias valve. A blocking rod (arrow) replaced the factory spring, another feature that raises fluid pressure within the transmission, leading to firmer clutch application and therefore firmer and quicker shifts.

The second alteration happened at the MTV upshift valve, where the factory spring is removed. This simple change will prevent the dreaded "700-R4 3-4 Shuffle." In other words, the tranny won't switch back and forth between Third and Overdrive at part throttle.

We requested a little extra before B&M finished with our throttle body, namely a Kickdown kit. Stock 700-R4s will downshift from Fourth to Third gear anytime there is more than half throttle is applied. The replacement valve prevents this forced part-throttle kickdown, allowing high-speed cruising in Overdrive. With this new throttle-valve-plunger sleeve (arrow), the transmission will only kick down from Fourth to Third at 3/4 throttle.

With that done, it was time to button up the bottom end of our newly buff 700-R4. The valve body is in place, along with the selector-lever detent spring (1), the wiring for the torque converter clutch solenoid (2), the throttle-valve linkage (3), the 1-2 accumulator housing (4), and the auxiliary valve body (5). Once a new filter was in place, we were ready to slap a pan on this thing. All that remained was the speedo gear and tailshaft housing; then testing, as seen in our lead photo. With that, we were ready to go.

We're not covering the installation of this tranny in our Z28, but B&M sent us out the door with what we'll need to do the job right: a case of Trick Shift performance automatic trans fluid, a SuperCooler, a HoleShot 2400 converter, and even a new TV cable. We'll be installing all these goodies in our Z in the weeks to come--which means we'll finally get to drive the thing!