I have 2009 Lincoln MKX AWD (TAURUS). Car has a dip stick and drain plug on the trans case. I'm old school and fluid is cheap and transmissions are expensive, so every 24000 miles or so, i would pull the drain plug and dump the fluid. I was using Valvoline Mercon V until I couldn't buy it any more. Also have 2014 Lincoln MKZ 2.0 AWD (FUSION). Bought fluid for that car and it was Mercon LV. Like a dumbass, I assumed the fluid was the same, pulled the drain plug and filled the MKS with 5.5 qts of Mercon LV. That was Feb 2019 and 6000 miles ago. I went to buy more trans fluid from the Motorcraft distributor, and recently bought 16 MKX (EDGE). Thinking the MKX might take different fluid I asked if all 3 cars took the same fluid, when i found out the 09 MKS runs Mercon V and the 14 Z and 16 X use the Mercon LV.

6000 miles later I haven't noticed any problems. I have been reading that the LV is a synthetic. Also have read that you can't mix them. Like I said, I haven't noticed any issues at all. Has anyone made the same mistake? Does anyone have actual better knowledge why these fluids are not compatible and could I have done any damage to my trans? Again, it seems to run just fine. I have just now dumped the fluid and replaced it with the Mercon V, but in theory that leaves 4 1/2 qts of fluid that is 50% Mercon V and 50% Mercon LV.

Hopefully looking for a knowledgeable ford trans guy out there....

 

I think Mercon LV is better fluid that you can use in Mervon V applications as shown in this product information sheet:
https://sharena21.springcm.com/Publi...2-ac162d889bd1

 

Thanks for the information. According to the Valvoline document, you can use that fluid for Mercon, Mercon V and Mercon LV. After an abundance of caution, I ended up having the trans flushed and new Mercon V installed. One year later car now has 106K on it with no trans problems. I couldn't find any information from Ford where the you could substitute LV for V.

 

In my case it was easily avoidable. I dropped the pan twice including filter change. The 3rd charm I brain farted and bought a jug of Mercon LV. Labeled right on the jug and still put it in. I recently changed the seal and fluid in the transfer case which takes the LV fluid. Didn't even blink an eye until a week later. Going thru the garage I happen to look at the empty 5 qt. LV jug I was saving for used oil. The light bulb went off plus a blown fuse. After lots of research I've concluded they are not compatible or risk transmission damage. Dear fellow brain farter(s), do not leave the LV in a Mercon V transmission. Even you haven't noticed any difference, the LV is lower viscosity among other differences. Think putting 5W20 in a 5W30 engine for easy comparison. Probably worse with the transmission mix up. Guess what I been preparing to do. Glad I have my solid 4.6 21 yr. old as a reliable backup. Yes I feel like a dombazz.

 

Took to a Ford dealer and had the trans flushed. Car now has 120K on it and runs great.