It is difficult for us to tell you what might cause the hissing noise as we are not able to determine the source. Does it happen when revving up?
When rpm is high but car is not speeding up, it should be the trans not up-shifting or is slipping. Check the ATF level, low level can cause slipping and damages if used over a period of time.
Thursday, July 10th, 2008 AT 9:50 AM