Donald Trump has recently talked about implementing tariffs on American companies and moving their factories to other countries. He also has talked about increasing the taxes on the compensation of hedge fund managers. Republicans have been known to consistently preach cutting taxes and bolstering business to help economic growth. http://mobile.nytimes.com/2015/09/01/us/politics/republicans-wary-of-donald-trumps-populist-tone-on-taxes.html?_r=0&referrer=
Traditional republicans are in shock but the huge difference in Trumps view of taxes. They fear the Trumps opponents may start to adopt a more tax admitting stance to gain some support from some people on the fence on Trump. However, traditional republicans do not want to see a tax allowing nomination represent the Republican Party.
Many republicans are fearful because while Trumps view on taxes may not align with republicans it does support the feeling of a great deal of voters. The club of growth is an anti-tax group that is investigating Trimps tax plan and is seeking to find flaws in it. http://www.washingtonexaminer.com/donald-trump-is-set-to-blow-up-gop-orthodoxy-again/article/2571075
I feel that Trumps view on taxes is a great risk for many Republicans. if Trump is seeking a tax increase, his opponents are going to be forced to allow for taxes at a greater frequency because they want to lessen the gap between themselves and the current leader of the polls. However, by doing so, the candidates are going against the orthodox republican view on taxes and this could become a big problem if some of their votes leave for a third party candidate in the election for presidency.