need help asap

I was driving my 95 astro home the other day. as i was leaving the toll booth the tranny did not shift from 3rd to 4th. i shifted out of overdrive and back to see if that was the problem but upon doing that the engine started squeeling and knocking really bad. the oil pressure dropped and the engine died. now when i start it, it still squeels and knocks and there is no oil pressure unless reved. I'm pretty sure that it is the oil pump but i'm just seeing if any of you had a similar problem with different results before i start ripping it apart.

Squeeling and knocking is not good- the engine would not shift to 4th most likely because the RPM's were not enough- because it was fighting internal friction so bad- it was all it could do to stay running- I experienced this same thing once- the engine actually seized- then ran again once cooled down overnight- but knocked bad-- the rod bearings were shot- once I opened it up- loss of oil pressure may be due to a cracked oil cooler line- which was known to happen occasionally- was it leaking? I ended up buying a junkyard engine for $500 (87,000 mile) and installing it myself- sorry to say it but your too late to try to fix this engine- unless it has really low miles......

no there was no fluid leakage at all.