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Just rebuilt my first tranny. it is a c4 in a 79 truck. Bought truck with bad tranny. Tore down the tranny to find forward clutch pack burnt up, so i rebuilt it. now i have 1st gear but slips in second then is ok when it goes into third,and reverse works fine .so what is wrong?????????
Well that's no Fun!!!! But maybe you aren't too far from having it working.
The C4 has just 2 clutches, but has 2 bands, right?
I would think that for 2nd gear, the Forward Clutch and the Intermediate Band would be applied. Since 1st gear also uses the Forward Clutch, that would seem to say that the Forward Clutch is OK.
So what about that Intermediate Band?
Did you soak it in trans fluid just like the clutch frictions before installing it?
Is the Intermediate Band pre-load adjusted properly to spec?
What about the Intermediate Servo? Did you replace the piston or seals on it?
Intermediate Servo springs and/or Servo piston parts inserted in the proper order?
I'm assuming that you carefully took the valve body all apart, cleaned it, and oiled the spool valves with ATF as you carefully reassembled it properly