I put the tranny into gear in both forward and reverse goes in good but when I go and accelerate it makes this god awful noise. But it's only when im going. Yes and I'm aware I need a tranny but I want to see if I can do it myself. I'm a noob at this so im doing my research so just bare with me. I do work on vehicles but not atvs. First time. Yes I rather do the work myself. Do I need a new silent chain?

 

Check the outer drive sprockets and chain especially the front sprocket. You may get lucky and find that it's worn down the spines causing the slipping. If this area is ok then sounds like the old stretched silent chain problem that many of the single range gear cases had problems with over the years. Actually more trouble to get out of the frame than to split the gear case and replace a 40 buck chain. This one has that old funky combo drain/ gear case brace plug.If you've changed gear case oil before then you know what needs to be done. If not,the lock nut on the small bolt has to be loosened and the bolt screwed in far enough to get the drain plug out of the gear case so it can be remove from the frame. After assembly reinstall the plug, bolt and nut together,tighten the drain plug,loosen the inner bolt until it touches the lower frame,the turn 1/2 turn. Then tighten the lock nut against the drain plug. Here's a video on a loose busted chain.