4L60E No Reverse!
We have built many 4L60Es but this one struck me as odd. This vehicle came in with no codes and a little over 200,000 miles on it. When we tore it down all the clutches looked great. It just had no reverse all at once.

Upon air testing the reverse input drum we could here a little more leaking than normal. We all know this drum doesn't air test super tight because of the design of the piston to wave plate seal. Upon close inspection we could see that the drum cracked in place we are not use to.

So I posted this just in case someone get one slipping in Rev. The way I found it was to fill the completely dry drum up with solvent where the piston goes, then I sucked the solvent out and tilted the drum and seen that solvent had leaked in between the drum in a drum. - more