zf6 fluid question

[Hawker]

i was talking to a tech at the ford commercial truck dealer and he said for put out a notice (not sure if it was a TSB or not) about 'gear chatter' in the 6 speed. he said to get rid of the chatter, they swapped the semi-synthetic factory fluid with a straight 30 weight oil. anyone else hear of this?

[AFBLUE]

Not anything that I know of. I just put $85 of royal purple Max ATF in my trans, not about to switch to anything else right away. I think it shifts better than the old oil that was in it, but that might be becuase the old ATF was shot. I have I guess what you would call a chatter, but its at 0-4mph, if I am in 2nd gear, and should be in 1st.