The second and more critical part is reinstalling the cover retaining spring.

The right side exhaust down tube passes by the area where the servo housing is located. The hardest part is getting to the servo housing and removing the spring clip and cover. Your ultimate results will depend on how healthy your valve body is (because this is where other shift problems with the 4L60E are addressed) and whether or not you've installed a valve body shift kit. nothing uncomfortable but sort of the way it should have come from the factory. In my case I noticed a small increase in shift speed and firmness. In short, the tranny will shift a little quicker and a little bit firmer. There are different tension springs used and this helps develop higher line pressures to the clutch packs. The idea behind both these servos is they are larger and thus generate more holding pressure. depending on who makes it and is usually a custom-made billet servo while the other is essentially an OEM GM part. The 4th servo is sometimes referred to as a 'SuperServo' or something along those lines. The 1-2/2-3 servo is commonly referred to as the 'Corvette Servo' because this is what GM puts in those 4L60E's used in the Corvette (and Camaro's). They all live underneath that round aluminum cap you see sticking out the passenger side of the tranny. There are actually two servos the 1-2 and the 2-3 servo are combined and there is a separate 4th gear servo. Click to expand.This is probably one of the better, easiest and cheapest mods you can make to your transmission.

Ac delco corvette servo 4l60e