In addition, the 700 has a couple other weak points that include a weak sungear shell, and a weak input sprag, which both hold up fine, unless they are 'hammered on' by harsh shifts. (Remember, the original problem with a 700R4 is premature 3/4 clutch burn up, which has just been made worse by the technician who 'improved' the unit).

Number one: the 2nd gear band must release when the 3/4 clutches apply, to produce a 2nd to 3rd shift, so, when they increase the apply area of the band,(to make the 2nd gear shift harder), they also make the band release more slowly, and, together, with the 3rd apply hole, they drilled out, to make the 3/4 clutches apply more quickly, they produce a 'bind up' in the 700 which causes the 3/4 clutches, and the 2nd gear band, to burn up, prematurely, due to excessive heat. The 700R4 3/4 clutch pack usually burns up, as a direct result of a few different problems, all of which are not addressed by most technicians. In addition, to make the transmission shift harder into second gear, they change to a Corvette servo piston, which has more apply serface area. To 'fix' this problem, many rebuilders add an 'Alto' kit (or another brand of clutch pack, that are thinner, providing room for more clutches), and drill out the apply hole (which makes the clutch pack apply more quickly).

For example, the 700R4 transmission has a nasty habit of burning the 3/4 clutches.

Some transmissions do have shift quality problems that need to be dealt with. This shed some light:īy Example: The 700R4, and Why I Do Not Recommend Shiftkits in 700's. I'm trying to find out the perfect 'shifting' set-up for the awd.

Why corvette servo 700r4