Firewall rules for transmission

Solution 1:

So as I explained in the comments above, it was a typo I made Lol ... I had my INPUT udp port as 51513 instead of 51413 ...

But, just in case anyone wants to know, these are the rules that I have used to allow Transmission:

iptables -A INPUT -m state --state RELATED,ESTABLISHED -p udp --dport 51413 -j ACCEPT
iptables -A OUTPUT -p udp --sport 51413 -j ACCEPT

Thanks everyone for their input