No problem :D always happy to help, and i also was not asking you to change those things i was simply offering alternative ideas to help futher your own.

The problem with this logic is that HP does not equal tanky, a true DPS will tear through your health in a heartbeat as well as there are lots of abilities that scale damage with max health such as Warwick's Hungering Strike or the item Madred's Bloodrazor. Tanks carry such survivability through armor and magic resistance in addition to flat health because a relatively easy to achieve armor of 100 would effectively double your health against a physical opponent.
Now that being said, your build could use a little work, including replacing your Frozen Mallet with the all powerful Trinity Force. Much of that debate is personal preference but for the high cost of both, the triforce gives you far and beyond more benefits. Also you mention the CC reduction of Contaminate so why not build merc treads (which stack with contaminate) and make yourself impervious to crowd control, that's a smarter option for trundle since you only have one pair of boots and attack speed is really not necessary on trundle since your contaminate already buffs it by a considerable amount. Same goes for your seals, it would be better to take either mana regen/level or flat armor, or even health per level to capitalize on your Atma's Impaler passive. Btw sidenote, never build atma's before Warmog's Armor because you need to farm warmog's and atma's standalone stats are nowhere near the money unless you already have a significant health pool.

@ZealotRush I see alot how you think Zeal, but i am actually not gonna change the runes though the buff duration was something i have slipped pass and i am thankful you let me knew about it. I am not gonna change the runes, i have already tried an AD rune build and it did not work out quite aswell for me as with ATK speed and armor pen. Also i had no idea red and mallet stacked, its like a ****ing permanent exhaust. Thank you for your tips.

@zapatou As you see in the build i go 4.2k hp! With the lifesteal you ARE a TANK with insane dps, i have been up against 4-5 ppl alone a couple of times yet walked away with 2-3 and even 4 kills! Amazing hp + Crit + Lifesteal + Attackspeed = Immortality.
Man, i beat fed trynd's and zhao's. There is no need for more defense when your defense is your offence. Though i appriciate your opinion, thanks!

I like it. +1

I adore the items and the runes, great build/guide all around I think. Good job bro.

As a trundle player i use alot of the same items and overall i like the build :D your runes are alright too but ive noticed that for jungling flat damage marks work better because they allow your rabid bite to do just a smidge more damage which adds up in jungle, but thats just what ive noticed. I am, however, concerned about your masteries. You get the 15% magic pen which only really does anything to his ult and the extra point could be used better. To be honest im not really sure why you deprive your build of the 15% buff duration. I am bringing this to your attention because of the fact that you understand how great frozen mallet is. What im bringing to your attention is that if you get the buff duration and maintain red you will have a double slow on every one of your physical attacks (yes red stacks with frozen mallet) but overall i think this is a great build and i vote yes :D

i would appreciate it if you took a look at my trundle build and let me know what you think, as a trundle player your input is more important than most

good build but i feel like trundle should be an offtank not a major dps so i would recomend going 0/21/9 instead of 21/0/9
also trinity is awesome on him with his q plus it gives him some nice MS to get close to his enemies