B18B1LS1

iTrader: (12)

My car seems to have a bind in the 2-3 shift at part throttle, but only with the shifter in D. I know it uses the overrun clutch in D, does that have anything to do with it? Easy enough to drive around in OD and it's fine. I am worried there is still a problem in the tune or the trans itself and I'm not doing it any favors driving it. Any ideas?

mrvedit

I try to answer the 4L60E questions here, but I have no experience with this.
Until/unless someone here gives you better advice, I would remove the servo and replace its seals as a relatively simple first step.

Mystery Bird

iTrader: (7)

Do you have the stock or aftermarket 2-4 servos? Sounds like something in that circuit is maybe not releasing the band quick enough.

mrvedit

Good point. If you change from the basic servo to the corvette or aftermarket servo, IMO you need to drill out the 3rd feed hole in the separator plate.

What few people (even some trans builders) realize is that the 2nd gear fluid pressure is on the 2nd gear servo in 2nd, 3rd and 4th gears. Yes in 3rd gear too!
The 3rd gear apply fluid presses on the backside of the 2nd gear servo, and since this is a bigger surface area that the front side, disengages the band. However since the front side of the Corvette servo is bigger, the band will release a bit slower and could therefore cause a brief bind. Drilling the 3rd feel hole (in the separator plate) may therefore help get the band released quicker.
I hope that made sense.

performabuilt

iTrader: (25)

I would agree the band is not being released quick enough, And in fact in the D position you have a larger load on the fluid circuit because you are turning the overun clutch on where you are not in the OD position , In OD the overun clutch is never on but in D its on in 1st off in second them comes back on in 3rd.

B18B1LS1

iTrader: (12)

I don't know alot about the transmission. The guy I bought the car from said it had a "built" transmission but couldn't offer any more info than that. I pulled the vb and verified it did have a transgo kit and it was setup as aggressive as possible in the directions of the shift kit. But that's all I know so far.

mrvedit

You mentioned it has the Transgo HD2 kit installed. One step in that is to tighten up the servo by installing shims under the cover. In my limited experience with just a few trans, one shim is the correct number and two shims is too much. With the rear wheels up, engine off and trans in neutral (actually anywhere other than Park), try turning the driveshaft by hand. It should turn with modest resistance in one direction and about 3 times harder in the other direction. If it is very hard/impossible to turn by hand, the servo might be too tight; you will then have to remove the servo cover and remove one shim, assuming one or two are there.
Performabuilt: do you think a too-tight servo might cause a bind?