4L60E Problems

Hello all,

I have a '93 Sierra extended cab with a 350, and a 4L60E automatic. Currently I have around 292K on the engine and trans. Heres the problem. A month ago I was driving and noticed it would not go into overdrive. This has happened before and was due to a low trans fluid level. This time the fluid level was fine, although a tad darker than new fluid. I parked it for 2 weeks, and when I drove it again, it wouldn't shift out of first. So I called around asking mechanics what might be the cause and they mentioned the shift solenoids. I'm positive its stuck in first, because from a dead stop it would throw you back in your seat by slightly getting on the gas (second is definitely not that stout in mine).

I put in new shift solenoids in the valve body and it didn't help a bit. I took out the servo and cleaned it, which was not really contaminated to begin with. I am at a loss and being a college kid, I don't have the cash to hand over to let somebody else work on it. the mechanics here wont suggest anything without hooking it up to a diagnostics unit first. My dad says it might be that the sun gear is worn out.
Does anybody have a clue what is the malfunction here???

well if you lost 2nd and 4th they both have the band in common so I would guess the band is burnt up.