I am thinking that this is the front pump going out, as it was a rebuilt one, but let me know what you think? The night before it went out, on the 7 mi drive home, it started surging slightly on the highway, made it home ok. Then the next day, halfway through my neighborhood, the rpms just went up after taking off from the first stop sign, then no power. Pulled over, stopped, tried putting it in 1, nothing, tried reverse, nothing. It was if it is in neutral, no response at all in engine or rpms when shifting between all gears. Is this a sign that the front pump went out, or could something else had happened? Trans fluid level is fine, still bright red. Was a used trans with a rebuilt pump that has been in the car for about 6 months.

 

As a non-expert on trans, certainly seems like either something got loose in the valve body till it found a channel to plug or the front pump was assembled wrong.
Thinking a pressure test should tell the story.
Hope you know an honest transmission shop. Ought to be {relatively}an easy fix... but again, I'm no authority.

 

Would pulling a coolant line then starting the engine test the trans pump? I assume if the pump is gone, that coolant will not spray out as it should if working, correct?

 

No.. that wouldnt prove much. Just same as this

https://www.google.com/search?q=test+pressure+on+4l60e