79 el camino transmission slipping

This problem came on suddenly. Slips in all gears. Fluid is pink.

TH350? Does it also slip when manually placed in L?

The fluid is pink, but is it full? Overfilled?

thanks. i will check it out

Thx. Finally got a ride in the vehicle. Belongs to a young friend I'm trying to help. As you suggested I had him start out in low and hit the throttle good and accelerated fine then into second with nice solid shift and no slippage, same into 3rd with a nice long hill started getting an engine twitch and oil pressure drop 5psi with each twitch but would not accelerate past 70 mph, just hold its own, did not notice a passing gear, about that time we got quite a vibration so as slowing test ride was interrupted by a blow out on the right rear. Any clues so far? Thx Merrill

If the trans is not slipping in manual ranges, the clutches and band may be O.K. The fact that the oil is still pink would also tend to indicate that there is no serious wear.

The question may be the line pressure control (modulator) and valving.