Transmission fluid capacity?

[FFEFTW]

Yes, I know our FFEs don't actually have a transmission, it's more a simple single speed differential gear set, and it's lubed with Ford Mercon LV ATF fluid. If I were to want to change over to some quality synthetic lube (Redline D6 ATF), anybody have an idea what quantity of fluid I would need?

 

[kalel14]

There is no service interval for changing this fluid. Why would you want to change this? Your battery will be dead before the normal interval for even a conventional automatic.

 

[jmueller065]

I'd bet the idea is to try and reduce friction even further to eek out that extra mile of range.

It isn't worth it. Do you go and replace the fluid in your manual transmission as well??

 

[FFEFTW]

I've done that on my regular ICE vehicles, swapping the motor, transmission and gear oils over to synthetic was good for a measurable 1-2 MPG bump.

I don't really expect to get the same scale of benefit out of the FFE, but it would be amusing to try if it's just a quart or two.

 

[jmueller065]

I've done that on my regular ICE vehicles, swapping the motor, transmission and gear oils over to synthetic was good for a measurable 1-2 MPG bump.

I don't really expect to get the same scale of benefit out of the FFE, but it would be amusing to try if it's just a quart or two.

Have you ever done just the trans vs just the motor oils to compare which has a greater effect?

Since the FFE only has a few gears and a diff I would expect the operation to be more trouble than its worth.

This is what you're looking at to replace the fluid in:

More pics can be found here: Ford Focus Electric motor exposed

 

[triangles]

Valvoline Max Life Multi-Vehicle ATF is a full synthetic that is slightly thinner than OE fluid. It's also meets the Mercon LV spec which is what the OE fluid is. I'm going to guess Ford just used Mercon LV since it's already very thin and is what they put in the ICE transmissions. Why stock another fluid if you don't have to especially on such a low volume vehicle.

My old ICE manual trans took Mercon V ATF. I would run 50/50 Pennzoil Synchromesh / Mobil 1 Synthetic ATF. The Synthetic ATF for low viscosity and the Synchromesh to provide enough stick for the synchros to work properly. Like you I saw a few MPG boost with this. Straight Synthetic was too slippery for the synchros to work well.

I had thought about swapping my FFE gear box fluid out for something else but I can't think of anything that would be less viscous and still provide adequate lube. Besides I don't want to risk voiding my warranty and possibly grenading my gears. I don't have another car to use until I get my Model 3. Please share your results if you do this. I for one am curious as to how well it would work.

 

[FFEFTW]

Stopped by my local Chevron Oil Stop this morning, the guys hadn't seen me in over a year so they were curious to see what I was driving and had lots of fun poking all around an electric car figuring out what's what. They found the drain and fill plugs, and found some records saying it's a 1.3q capacity, so I placed my order for some Redline D6 ATF and we'll give this a try for fun...

So any thoughts on how best to benchmark this? Long carefully repeatable freeway cruise to spin the gears at full speed and see what my watts/mile look like? Do the same but climbing a hill to put some load on the gears? Something else?

 

[EVA]

Fun. Good luck.

To measure the difference, you'll probably have to use some pretty big averages over the same route, or very similar driving. There are a ton of variables to control - most important one is temperature and how you drive. You'd want to make this as reproducible as possible.

If you drive the same route every day - isolate the kwh/mile values for that first time in the morning trip. I'd keep track of the outside temperature for those days. And probably split them between above 45 degrees and below 45 degrees. You're probably also calmer in the morning (I bet if you look at your history for the same commute, you'll see lower kwh/mile use in the morning than at night coming home). You'll probably need a good 20 or 30 commutes to get a good number.

Then when you get the new oil, do the same thing. 20-30 more commutes.

Here's the tricky part, you'll have to figure out the variation in each of the data sets, before and after. Calculate the standard deviation of both sets (spreadsheets have that function, so do some calculators). Then multiply the standard deviation by 3, and that number tells you if the difference you are seeing is significant. The more replicates you do, the better the standard deviation number.

More than likely, the variation of the two data sets will be so big, you won't be able to tell if there is a difference. It might look like the new oil gets 5 kwh/mile better economy, but when you factor in the variation of the data, the difference is insignificant. So there really was no change. On the other hand, maybe you will see a real difference.

The worst thing you could do is try to pair data, before and after, with single data points. More than likely you are going to try to drive more gently after you make the change, trying to get the result you want. You'd do that subconsciously. And it is perfectly normal.

The other approach is to just use your big grand averages to see if there is a difference, over a lot of trips and time. The biggest problem with that approach is temperature. You won't end up with data collected with similar temperature patterns. Well, unless you live in LA and it is 70 degrees all the time.

Given the range of the car, you probably are driving the car in similar areas. If you all of a sudden started driving in San Francisco, and you used to drive in flat LA - well that would be a difference. Generally you're driving similar terrain day in and day out.

 

[jmueller065]

I would add:
Find a long stretch of road with no lights, constant speed limit, and little to no traffic. Use the trip meter and cruise control down this stretch: Reset the trip right at the beginning when you engage the cruise control and (the tricky part) record the trip meter at the end just prior to disengaging the cruise (perhaps by mounting a camera pointed at the trip meter and video it--just mention when you disengage and later take the reading then).

Measure that repeatedly along with the temp like EVA mentioned.

 

[triangles]

I placed my order for some Redline D6 ATF and we'll give this a try for fun...

The Redline oil you're putting in there will theoretically hurt your efficiency NOT improve it if specifications mean anything. No I'm not knocking Redline's products. They make some good stuff. Anyway back to the topic. Comparing the specs for kinematic viscosity and the viscosity index shows the numbers are all in the wrong direction for the Redline D6 ATF if you subscribe to the theory that a thinner fluid provides less friction. I'll list the specs in order of Motorcraft Mercon LV, Redline D6 ATF, and Valvoline Max Life Multi-Vehicle ATF
cSt @ 40C: 29.6 30.7 28.82
cSt @ 100C: 6.0 6.4 5.91
Visc. Index: 155 166 156

Redline has the highest kinematic viscosity at both temperatures. Higher viscosity is good at protecting gears so I guess you could say it'd protect better against wear. The viscosity index is the rate of change in viscosity between two temperatures. The lower this number the quicker the oil thins as it's heating up. Here again Redline is a higher value meaning it doesn't thin as quickly as the OEM lube. Redline's products are geared toward providing better protection on equipment that is used and abused (racing) which I believe their product would provide at least a theoretical higher margin of protection.

With the exception of the viscosity index the valvoline numbers go in the direction we want. The lube has lower viscosity than OEM and 1 off in the wrong direction of the viscosity index is negligible. Yes I know viscosity isn't the whole story, there are additives/friction modifiers that may be in a given lube but since viscosity significantly contributes to a fluid's friction it's easiest way to compare and usually points you in the right direction. Quite frankly all three of these lubes specs are so close you'd probably need some pretty sophisticated lab equipment to detect any meaningful difference. Oh and like the Redline, the Valvoline product is a full synthetic.

 

[bkeil84]

There are so many other variables that this test could only be done in a lab under strictly controlled conditions. Just a wind difference of a couple of miles an hour or even a change in direction would skew the results. And not to forget the amount of traffic, you might hit 5 lights instead of 4. Barometric pressure would have to be the same to account for the exact same amount of drag. In the end, even if it is better it would only account for a mile or 2 of range on a full charge. Sounds like a lot of work for an unverifiable increase of efficiency for a few bucks a year savings.