Mercon LV in my '07 Focus

[Klutch9]

The '05-'07 Foci spec Mercon V for automatic transmission fluid. However, the same engine/transmission combo in the '08-'11 Foci specs Mercon LV fluid. The LV stands for 'low viscosity' IIRC, and as put in place to net some MPG gains I think. Any reason I couldn't run this fluid in my Focus? The transmission is the exact same as the '08-'11s had. Right now I'm actually using MaxLife ATF which claims to meet/exceed both Mercon V and LV. Supposedly, Mercon LV expands more when hot.

 

[bdcardinal]

FWIW our ATF charts for service show LV being backspec'd for your vehicle.

http://fcsdchemicalsandlubricants.com/main/quickref.asp

 

[Klutch9]

Thanks for that link bdcardinal. Would you happen to have more insight on the differences between Mercon V and LV, and if I'd be better off using one of those fluids over the MaxLife ATF I'm using now? I've seen articles stating that V and LV are not 'interchangeable', yet it never states whether or not they can be mixed. I'm assuming they CAN safely be mixed. If a transmission gets back-spec'd to a different fluid, there is no way to completely remove the old fluid of a different spec before adding the new one. So in my mind, they must be able to be mixed safely... logic would dictate this.

 

[bdcardinal]

I would say that without a complete rebuild with all new internals then most likely the fluids will mix. Maybe replace the filter when you start adding the LV.

 

[Klutch9]

I was looking up and comparing the viscosities at 40C and 100C for both the Maxlife ATF and Amsoil's LV equivalent, and both look quite similar at both temperatures. Normally, Mercon V hovers around a 7.3 at 100c, whilst the Maxlife ATF is 6.3, and the Amsoil LV equivalent is 6.0.

 

[tig1]

I am using Mobil 1 ATF with very good results in my 07 Focus. I do about 40K OCIs and the fluid stays clean. Also I use it in my PS pumps as well. I change the filter every 75K.