Convert Your 4L60E To 4L65E Specs

With the First and Reverse clutches installed, Straughn suggests using a block saver. This $6 clip keeps the low/Reverse overrunning clutch from rotating and breaking the case.

Cleanliness is a virtue, especially when it comes to transmissions. The case for the 4L60E was washed for a few hours in a hot bath. Since hot tanks have pretty much been outlawed by the EPA, 250-degree water and soap had to do.

The clutches were soaked in a bucket of Dexron III before being installed in the tranny. Forget this step and you may as well throw it all away.

The high-intensity band was installed after the drum was dropped in. It took a little massaging to get the band to snap in place. For the 2-4 band, Straughn suggests using a late-model high-intensity band over a wide band. The wide band has little more hold, but the high-intensity band grabs and releases faster, which is more important in a high-performance application. The wide band is better suited for towing or in cases where the drum is worn in the center and replacement is cost-prohibitive.The servo pin was checked for clearance and was in spec, so the washer was installed.

The Z-pack clutches were installed in the drum and checked for clearance. The clutches should be stacked in this order: friction clutch, steel clutch, friction clutch, and so on. The final clutch is the brown clutch. The clutches have been stacked correctly when the brown clutch is even with the snap-ring groove. Then the five anticentrifugal rev springs are installed, followed by the pressure plate and another snap ring.

The Sonnax servo was installed with a snap ring to hold it in place. This unique piece offers 40 percent more surface area for better holding power in Fourth gear. This helps eliminate band failure in high-performance applications. It is simple to install with only a set of snap-ring pliers required. Just be sure to use the supplied steel washer. There is some adjustment to be made here, though: The typical travel of the servo pin is 0.125 inch; if it is greater than that, the pin should be changed or carefully ground down to achieve the desired travel.

The pump assembly received a new main pressure regulator and boost valve, which came with the Trans-Go reprogramming kit. The separator plate rests between the transmission case and the valvebody, and has 10 holes that require additional drilling. These are the pressure-apply and relief ports. Opening these up to 0.093 inch increases shift firmness and adjusts the timing of each shift. Straughn also suggests drilling out the solenoid A and B ports to 0.040 inch. He has found that this slightly increases shift time, which makes for a nice shift pattern on the street.