Synthetic mixing with non-synthetic

[martin123]

Hello

What happens if not all the fluid is removed and it is conventional fluid (ATF, 5W30, gear oil), and then it is topped up with synthetic? For example you had a transmission flush a year ago, now you want to change the filter, is it ok to top it up with synthetic, even though there is a lot of conventional ATF still in it? That would be the worst case I could think of.

Thanks

 

[aldive]

Nothing bad will occur. However, depending on the ratio of the oils, you might not be getting the full benefit of using synthetic.

 

[martin123]

That is what I wanted to hear. Thanks alot

 

[gijoecam]

If you mix synthetic witn dino-oil, you'll need to flush the system using 1 part kerosene, 1 part vegetable oil, and one part PAG oil. Otherwise the two oils will combine and form a cement-like particulate (ever seen a cement mixer shot??) that'll pulverize your oil pump and bearings into oblivion.

Just kidding... It's fine. Nothing to worry about. It even says so right on all the synthetic bottles I've seen.

-Joe

 

[martin123]

My jaw hit the floor as I started to read. Glad you followed it up with just kidding!!!!!!

 

[Dan Whitaker]

Good one Joe You gat the newb real good