What if I mixed Mercon and Mercon V?

[jmines]

Here's my long story in a short version. We worked on my sisters '00 Ford Taurus. We changed the ATF and filter. The service guy started by giving us the wrong filter. After we had the correct new filter on and the new fluid back in we realized that the dipstick said Mercon V only. Well the service guy sold us Mercon/Dextron III. I read that I can add Lubegard addative to the fluid to make it equal to Mercon V. Well my question is that since I did not drain the Torque Converter I basically have half Mercon and half Mercon V in there. I don't think the fluid has ever been changed because it was brown and there was a film of sludge on the drain pan bottom. Am I in trouble and need to do a complete flush or can I just add the Lubegard addative and call it good? I have read several places that you cannot mix Mercon and Mercon V but I can't find out why.

Thanks so much for any help in advance.

[umina]

Originally Posted by jmines

Here's my long story in a short version. We worked on my sisters '00 Ford Taurus. We changed the ATF and filter. The service guy started by giving us the wrong filter. After we had the correct new filter on and the new fluid back in we realized that the dipstick said Mercon V only. Well the service guy sold us Mercon/Dextron III. I read that I can add Lubegard addative to the fluid to make it equal to Mercon V. Well my question is that since I did not drain the Torque Converter I basically have half Mercon and half Mercon V in there. I don't think the fluid has ever been changed because it was brown and there was a film of sludge on the drain pan bottom. Am I in trouble and need to do a complete flush or can I just add the Lubegard addative and call it good? I have read several places that you cannot mix Mercon and Mercon V but I can't find out why.

Thanks so much for any help in advance.

These transmissions are VERY sensitive to the type of fluid. Mercon V is semi synthetic in an attempt to help with heat dissapation. If I were you, i'd drain it from the pan and or pump it out of the filler tube and replace with Mercon V as reccomended in the owners manual. Do you really want to take a chance with a transmission that by itself isn't that good to start with?

[mwt878991]

The tranny is not going to explode because you didn't put the MerconV in it. The MerconV has and friction modifer in it that III doesn't.

Buy a bottle of the Lubeguard and you will be Fine.

I run Mobil1 and a bottle of the Lubeguard because my friend that owns a tranny shop told me that's what he uses. He is a standup guy and would have to warranty anthing he rebuilt that failed.

Mike