I have found that trundle is one of the much stronger jungles in the pre-season 5 meta. His extreme damage potential as well as great utility and split pushing makes him very versatile in most situations.

most guides tell you to get the dmge/armor pen jungle item. I do it different and you will see why. i get devourers for many reasons. one being it is broken as all hell. the attack speed greatly increases your clear speed and your dmge output during ganks. trundle has great lvl 3 ganks so be sure to put a point in all abilities by level 3, then immediately head to a lane that can be ganked.

if you are on purple side, start gromp, smite it, and the you will be lvl 2 to solo blue. like wise for blue side,start with golems and smite them.

when banking with trundle, there are a few ways to do it. naturally, like any jungler, sneaking up behind them is best. now, there is debate over whether you should open with your E, or engage, then halt their escape with your E. both work effectively. my play style is burst, so I want to rekt them before they even have the chance too escape, so I open with E and that also allows your lanes to engage on them easily, usually securing a kill. As far as W, don't use it to catch the enemy unless u must. I much prefer to use it AFTER i am already attacking them, that way I get more duration on the atto speed boost on them, plus the extra duration for running them down.

this is trundles strongest point. by now, you should have a few stacks on your devourers, your triforce, and maybe even your botrk. now... you rekt. 2 options: you can either hunt down their carries (or tanks cuz trundle is a tank buster) and get the solo kills. doubles if ur good. other option, split push for days. trundle is one of the strongest split pushers, especially with this build. his Q works on turrets, therefor 1 Q deals insane dmge and proc triforce.