shifting
Now to the issue. 1st 2nd and into 3rd gear are perfect and smooth but 3rd into 4th, 3rd gear seems to wine longer than it should take, like its delayed going into 4th, it hits 6,000rmps before shifting to next gear, doesnt seem right.note, this is W.O.T. or at least 3/4 throttle. its a 4l60e with a speed shift kit. my guess is one of the 6 clutches that engages 4th is probably slightly jammed up delaying shifting or something like that. Am i thinking too much into the wining and its supposed to be like that? Please someone with tranny knowledge help me. the car has about 430+hp with 3.73 gears with a speed shift kit 4l60e
When shifting from 3rd to 4th, only the band engages.
If the 1-2 shift is good, then the band is good.
However there is a separate servo piston for 4th gear. A cracked piston or leaking seal on it could result in a slow shift.
Shifting is completely controlled by the PCM. Therefore the first step is to determine if the delay is due to the PCM/tune or the trans itself. A good scanner, like what a trans shop has, can be used to command shifts. A test drive with a friend/mechanic running the scanner and commanding the 3-4 shift could help determine the problem.
I have no idea what a "speed shift kit 4L60E" is. Please give us more info or a link.
Assuming the problem did not exist before installation of the HD2 shift kit, I would first suspect a servo problem, e.g. backwards 4th piston or torn seal. Next I would suspect a torn separator plate gasket or a mistake in updating the valve body.
Good luck and keep us posted.








