rollinna65

iTrader: (18)

hey guys i've got a 2000 z28 and want to swap from synthetic back to regular ATF cause the synthetic has screwed up my 2nd gear synchro (previous owner put it in there). is there anything i need to do to flush out all the old fluid or should i just put the new regular stuff in there and drive away?

rollinna65

iTrader: (18)

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Igniter

How did you come to the conclusion that synthetic dextron III approved fluid was the cause for damage to your transmission?

calhoon

iTrader: (6)

He said nothing about an approved oil.
You can"wash" the prior oil out by circulating some new oild and draining. Then install the correct fill. I suspect that you don't need to do this as the new oil will dillute what residual is there. It may take some miles to realize the affects of the change. It may also be that just anoil change will not reverse the synchro damage.

Igniter

True about the right kind of synthetic, however, I wanted to point out that his supposed synchro damage was not the result of using synthetic instead of regular. Do you know what kind of fluid the previous owner put in? What calhoon said is your answer though.