Outboard gear inserts

I recorded some guitars and now felt I should have added one of my filter pedals. Instead of re-recording... is it possible to route he signal out and back in the MPCX without signal loss? I actually did it but he sound got super distorted coming back in the X so I figured there must be a 'right way' of doing this. No info on the manual.

try adjusting the input volume on the pedal? guitar output should be much weaker than your mpc`s output i guess...
if this doesn`t help, **** around with the input knob on the mpc... but the problem is most probably the other input knob )