HELP!!! How does this happen

[jons240sx]

So yesterday i finally finished my 5 spd swap..[hooray!]

so i went to fill the transmission with gear oil. and to do so i drove the car up on ramps, not a good idea i know but i was at the f*** it get it done asap stage. anyways the engine was running fine when i put it up on the ramps, filled it with gear oil everything went normal. then when i took it off the ramps to go on my maiden voyage with the new 5spd the engine started knocking like a ridiculously horrible rod knock.. how did this happen between me putting it on ramps filling it with gear oil and taking it off of them? what is going on?!

[Warped161]

is it the original motor? whats your oil level like? (in motor)