I had a '99 Silverado that had trans probs- that was a 4L60E, and the failure was the reverse/OD ring fractured. The only symptom I got, was that it had no reverse... I had to put my daughter at the wheel, and get out and PUSH it backwards to get it out of a parking space.
The bill was rather high... I think it was around $2400 all done, but they also found lots of slop in the T-case chain, and there was wear in the T-case that fortunately wasn't lethal, but they DID put an oil pump wear plate, and used all upgraded aftermarket parts in the driveline.
Sad thing is, after spending all that, about two weeks later, it ruptured a brake line, and the #%^% ABS pump totally evacuated the braking system... I stepped on the E-brake pedal, and the cable under dash promptly broke. Fortunately, I had a well-laden trailer in tow, and said trailer had electric brakes, so I whipped the gain knob to full-monte, and locked 'em up... it looked ugly, sounded ugly, but got me stopped in time to prevent becoming a hood ornament on the crossing Peterbilt...
The cost to replace the entire braking system (and they would NOT do it any other way) exceeded $5k.... so I sold it as-it-was.
