The flaring that Chike had, is not the same as the typical flaring, that we get on the 2nd/3rd gear change. When this happens the band just releases early, before the high clutch has applied. This does not wear the band as it is not slipping.
In Chikes case the band is slipping big time. What happens is, in first the forward clutch is on, to go to 2nd, we only have to apply the band to brake the front sun gear to a stop. This gives 2nd. What has happened is that when the TCU sent the signal to change, the band was applied but slipped too much, to stop the drum from spinning. It was only when the engine 'over rev cut out' came on to cut the torque, that the band could stop the drum from spinning. So from the time the signal for change was sent at 5400 rpms till the torque was cut at 5750, the band was burning up.
Why this happened is the way the changes are set up to take place. Subaru has allways tried to have the changes as smooth as possible, with no thump. It is this action that has caused the problem that Chike has found.
When the TCU sends the signal to the shift solenoid, it switches to allow a pilot pressure to move the shift spool valve across, to open the ports and direct line pressure, to the brake band servo, to apply the band.
If this was all that happened, there would be a big thump as the band suddenly stopped the sun gear drum. To soften the change there is another unit called the 2A accumulator. This is a little hydraulic cylinder, with a piston and spring, that is connected into the line going to the band servo. It acts to soften the application of the line pressure on the band servo. The pressure builds up gradually as the accumulator piston is forced back against the spring. This causes the band to slowly apply to change into 2nd. without a thump.
What needs to be done is to send the valve body away to one of the good auto box builders (DRG, Level 10) . Get them to alter the spring or orifices, to allow the pressure to rise quicker, so the band is applied with less time to slip. I reckon you would only have to explain the problem, for them to know what to do. This modification will make the changes harder,and the box will not be as smooth, but it will make it survive the treatment longer.
Harvey.
