727 2nd to 3rd flare up
On the 1-2 shift, all that happens is the kickdown band applies to stop the front drum from turning. In 3rd gear, the front drum needs to turn again so the kickdown band has to release and the front clutch has to apply at exactly the same time. The timing is critical.
If the band releases before the clutch applies, you will get an RPM flare up and/or a slipping sensation. If the clutch applies before the band releases, the trans will momentarily bind up and it will feel like you hit the brakes. This will burn up the band and front clutch in no time.
The timing is controlled by the kickdown linkage, which you already adjusted (wide open, all the way back is fine,) the kickdown band adjustment on the side of the trans, the throttle valve and line pressure on valve body. If all of these are adjusted properly and you still have problems, the there's an internal transmission issue.
Try the kickdown adjustment next. Loosen the outer nut, turn the adjusting screw (the inner part) 'til it's nice and snug, then back it out exactly 2 full turns and lock it down.
I doubt the throttle valve adjustment and line pressure have changed unless someone has messed with them. Has this trans been apart? If this is the original trans, it probably has the narrow front drum bushing which is known to cause the front drum to sag and rub on the reaction shaft support. I don't remember what year they went to the wider bushing ('70/'71?)
Keep in mind, the 2-3 shift will never feel the same as the 1-2 on a stock trans, but there should not be any flare up or binding either.
On the 1-2 shift, all that happens is the kickdown band applies to stop the front drum from turning. In 3rd gear, the front drum needs to turn again so the kickdown band has to release and the front clutch has to apply at exactly the same time. The timing is critical.
If the band releases before the clutch applies, you will get an RPM flare up and/or a slipping sensation. If the clutch applies before the band releases, the trans will momentarily bind up and it will feel like you hit the brakes. This will burn up the band and front clutch in no time.
The timing is controlled by the kickdown linkage, which you already adjusted (wide open, all the way back is fine,) the kickdown band adjustment on the side of the trans, the throttle valve and line pressure on valve body. If all of these are adjusted properly and you still have problems, the there's an internal transmission issue.
Try the kickdown adjustment next. Loosen the outer nut, turn the adjusting screw (the inner part) 'til it's nice and snug, then back it out exactly 2 full turns and lock it down.
I doubt the throttle valve adjustment and line pressure have changed unless someone has messed with them. Has this trans been apart? If this is the original trans, it probably has the narrow front drum bushing which is known to cause the front drum to sag and rub on the reaction shaft support. I don't remember what year they went to the wider bushing ('70/'71?)
Keep in mind, the 2-3 shift will never feel the same as the 1-2 on a stock trans, but there should not be any flare up or binding either.
