Q: Can the stock yoke on the driveshaft be retained?
A: Yes, both transmissions use the 32-spline output shaft.
Q: Can my stock torque converter be retained?
A: No, the SuperMatic has an electronically-controlled lockup converter that is a different design than the stock Turbo 400 converter. Besides, a new converter is included with the transmission.
Q: Do I have to replace my shifter
?
A: No, the stock shifter can be retained and will work fine, but you won't be able to shift manually down to First gear because the stock detents in the shifter are set up for three forward gears and the trans now has four. However, the shifter can be upgraded to add the Overdrive gear on the indicator and incorporate all four gears into the shift detents with a kit from Shiftworks.
Q: How will I get my cable-driven speedo to work with the electronic transmission?
A: With a tailhousing swap kit from Shiftworks that is set up to retain a mechanical speedo gear.
Trans Removal
Removal of the Turbo 400 trans is time consuming, but very straightforward. The steps include; disconnecting the battery; getting the car safely on the lift; removing the driveshaft; dropping the exhaust from the headers; taking out the starter and the headers; supporting the trans with a trans jack; removing the cooling lines, the shift linkage, the vacuum modulator hose, the kickdown switch, the speedo cable, the crossmember, the converter bolts, and the trans bellhousing bolts. While most items are fairly easy to remove, long extensions and universal joints for the sockets will help with the headers and the trans bellhousing bolts.
With the new, longer Moroso...
With the new, longer Moroso dowels (PN 37932) tapped into place, the Trans Dapt adapter plate (PN 0061) was installed using the supplied 3/8x24x1 flat-head socket screws.
The fresh TCI flexplate was...
The fresh TCI flexplate was installed using new ARP Pontiac flexplate bolts (PN 200-2904) with light oil on the threads to get an accurate torque reading and torqued to 95 ft-lb in three passes using a crisscross pattern. Then the Trans Dapt torque converter pilot bushing was slipped into the end of the crankshaft to take up the gap between the crank and converter due to the adapter.
Before the 4L85-E SuperMatic...
Before the 4L85-E SuperMatic was bolted in, the issue of how to run a cable-operated speedometer with an electronically controlled transmission had to be resolved. For this project, it was accomplished by using a Mechanical Speedometer Kit for the 4L80-E from Shiftworks (PN SW44-A) that features a new tail housing, drive gear, sleeve, and driven gear, sleeve retainer, and nut to run the factory speedo. All Melvin had to do was tell Shiftworks which type of tailshaft the trans had, as two were used during the production of 4L80-E and 4L85-E transmissions, and then provide the rear-gear ratio and tire diameter, so the correct speedo gear could be sent.
With the stock tailhousing...
With the stock tailhousing removed, a collar with a gear that will ultimately mate with the speedo gear was slid over the output shaft. It was then secured to the shaft using small Allen-head screws. Blue Loctite was used to ensure the screws stay put.
Next, the new tailhousing,...
Next, the new tailhousing, with the supplied o-ring seal in place, was bolted on and the speedo driven gear and sleeve assembly were lubed with high-temp grease and installed, while ensuring that the gears meshed.
Lastly, after clocking the...
Lastly, after clocking the sleeve so that the retaining bracket could be properly seated, the nut is then tightened.
Here's a comparison of the...
Here's a comparison of the new tailshaft (left) to the old, which are both 55/8 inches long. The only difference is the mechanical-speedo-gear set up on the Shiftworks piece. According to the company, this swap will not affect the electronic operation of the trans.