4L60E transmission changes VR to VS -

[hako]

Found a site that talks about changes made in 1995 to the 4L60E transmission and how to alter these changes so that the later trans will fit earlier cars. Maybe it can be used in Commoders VR/VS. In part it says:
"Why? In 1995, GM added a second control solenoid to the 4L60E Torque Converter Clutch (TCC) to allow them to control the way the lockup felt. The original on-off solenoid enables lockup, and the new solenoid (the "apply" solenoid) controls a slide valve in the valvebody via "pulse-width modulation" (PWM)- what that means is that the solenoid is turned on and off rapidly but the time "on" and the time "off" are varied like a fuel injector (like "duty cycle") to control the amount of fluid released by the solenoid, and this controls lockup. Smooth shifts are easier on the drivetrain with little loss in performance. That said, the valvebody valve acted upon by the PWM solenoid tended to wear the bore and cause problems (Sonnax makes a repair kit for this). Additioanlly, the smaller-diameter converters that performance enthusiasts swap into their vehicles don't have much clutch surface area and so they aren't as slippage-tolerant. Finally, if you're putting a '95 or '96 transmission in a '94 vehicle, the '94 electrical system doesn't have provisions to control the PWM solenoid and so you will have no lockup at all if you leave it as-is."

Site is at: 1870 Fix - 4L60E "mod A method 2" 95/6 -> 94 - Impala SS Forum

[chrisdoesitbetter]

nice piece of info, i have found that the vr and vs trans do shift and react alot different, even thought i always thought they were the same.