EcoBoost Trans Fluid Level

I recently purchased a '14 F150 w/ 3.5 EcoBoost. I’ve been experiencing hard shifting now and then and suspect it may be due to it running w/ an excessive amount of trans fluid. I have checked the underside dipstick off the pan, have drained 400ml from pan, lower dipstick indicating so, but no change in topside dipstick even after starting engine and shifting through gears several times. Trying to understand why this is. I plan to drain the extra fluid as well as another 375ml so to add a can of trans-tune before I do a drain and fill in a couple weeks.
Why don’t the two dip sticks match? Thanks in advance for input advice.

A drain and fill does nothing.


It seems like newer automatic transmissions are generally more sensitive to transmission over-filling and under filling than the older ones. This might be helpful

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When I do a trans drain & fill, I use the hoses off the cooler which allows me to drain & fill all the fluid.

Thanks, yeah even my wife’s 11yo V6 Escape seems to insist on a specific trans fluid level to run properly.

It seems as if the trans fluid pan/valve body, and wherever the topside dipstick read from are two separate areas/compartments as the underside dipstick which reads from the valve body/pan area is under vaccum whereas the topside dipstick isn’t. Was hoping to get a bit better understanding of it than that but it seems as if it might be make/model specific.

I don’t think a 2014 f150 came with a “topside” (or underhood/regular) dipstick from the factory. I think they only came with the little screw in dipstick down by the trans pan. I guess the underhood dipstick is aftermarket. May not be as accurate, maybe. I’d just go with what the dipstick down underneath says.


Yeah wow I think you’re right. Should I be surprised that it was possible to install an after-market stick, without affecting correct operation of the transmission? The dipstick on the pan is under vaccum afterall.
I wonder if this might be what’s causing the Rich condition.

I’m not sure I follow what you’re saying exactly. The aftermarket stick shouldn’t hurt/affect the operation of the transmission. I don’t think the trans is under vacuum anyway. It has a vent, after all.

And I don’t know what you mean by a rich condition when talking about the transmission. I’m confused on that one.

When you remove the dipstick that is on the pan, a vacuum noise is heard and felt.
So if the factory dipstick is under vaccum you’d think the whole system would be, except the dipstick that previous owner had installed is not.
As far as it possibly contributing to Rich condition, isn’t the Dipstick part of the PVC system? wouldn’t introducing unmetered air into PVC system represent a vacuum leak?

I imagine you’re feeling a vacuum at that lower dipstick hole because it’s nearly level with the pan and the fluid where the transmission pump is sucking the fluid up through the filter. In other words, the transmission pump is creating a vacuum of sorts down there. But that’s totally separate from the vacuum of the engine drawing in air.

Probably a stupid question on my part, but you are seeing an engine oil dipstick and a trans fluid dipstick under the hood, right? They only came equipped with an oil dipstick under the hood, originally. Then the transmission fluid is checked from underneath the truck. They do sell an aftermarket trans fluid dipstick, but I always assumed it replaced the short dipstick you pull when underneath the truck.