do i need visa 2 visit ireland with uk travel document?

travel document says yes but Garda (Irish Police) says no

Depends what you mean by travel document, if you are a citizen of an EU country - no, you just need a passport. If the country you come from is part of the Visa Waiver Program, no, you just need to fill in a form. If by travel document, you mean a uk passport -no. If you only have a visa to visit the UK, then you can't legally enter Ireland without a visa. That said, you could go to Northern Ireland.

As the North of Ireland is part of the Uk then obviously not. Crossing into the south nothing is required either. No check points nothing. Its just like a continuation of the Uk.