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MKZ 3.0 AWD transmission, laggy shifts

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Some shifts (in automatic, not manual shifting) are really slow to execute, especially 2nd gear to 3rd gear. Has anyone else experienced this?

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Unfortunately it is a normal part of the transmission behavior. All 6F series transmission vehicles will exhibit this at some point. Every vehicle I've driven with 6F35 and 6F55 (what the MKZ has now) is a sloppy mess if not cruising between 2nd and 3rd.

 

Firming it up with engine/transmission motor mounts and a tune by Livernois can help make it somewhat better, by becoming more aggressive. Though strict torque management and safety systems will still hold it back from displaying true power. While this has been a known flaw of behavior, proper fluid changes still should yield a healthy daily driver lifespan.

 

But the 6F family is old, and will never be refined for smooth performance. Therefore I am tired of settling for that transmission design flaw, and so no MKZ or Continental for me until a better one is made.

Edited by Zalvern

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5 minutes ago, Zalvern said:

Unfortunately it is a normal part of the transmission behavior. ... While this has been a known flaw of behavior, proper fluid changes still should yield a healthy daily driver lifespan.

 

Thanks for that. Sounds like it's a permanent (if dubious) feature of this car.

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Agree that it is very annoying. Sport mode helps bit for me.

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How is the 6F55 related to the other six speed's that Ford makes, the 6R60 and 6R80 trans? I read great things about the 6R80, but that was in the newer Mustangs, retrofitting etc.

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4 hours ago, CDW6212R said:

How is the 6F55 related to the other six speed's that Ford makes, the 6R60 and 6R80 trans? I read great things about the 6R80, but that was in the newer Mustangs, retrofitting etc.

 

The 6R80 is far more durable and programmed better for performance compared to the 6F55 (or 6F50, 6F35). Transverse based transmissions are always built with economical value in mind (lower production costs and fuel economy), over performance.

 

First number informs how many gears present (6 gears in this case), with the F/R indicating wheel drive layout (FWD or RWD based), and last number being the nominal max torque input capacity estimate. The last number is usually multiplied by 10, then presented in Newton meters which can be converted to pound feet of torque.

 

For the 6R80, you take the 80 and multiply by 10 for 800 N-m, which is then  about 590 lb ft of torque converted. Know that this is not a rating limit that marks when the transmission would fall apart due to going beyond the limit (many Mustangs go over 590 lb ft of torque yet stay stock on the transmission). It is just a marker for when transmission longevity is definitely expected to decrease faster than in stock form when exposed to over rated heat, rotational energy, and vibrations. If your vehicle becomes able to go beyond the limit, but you don't actually drive it every day demanding such power, it will last just as if it was stock then. Lifespan depends all on the actual usage, maintenance, and demand habits of the driver.

 

In regards to the 6F55, its only rated for about 550 N-m, which is about 405 lb ft of torque. This is why I suspect the 3.0 MKZ and Continental are really strict in unleashing anywhere near the real performance of the 3.0 Engine. From Lincoln's standpoint, the safety net is too small to allow for more performance and aggressive shifts to account for any valid factory warranty claims. Even if you tune them for more power, they're still going to hold back to a degree. These 6F transmissions are performance bottlenecks, as the 3.0 Engine is performance minded while the transmission (and PTU) are economy minded.

 

The same will apply to the 8 speed transmissions found in the Ford Edge ST for example, as I've seen people wishing the 8 speed would replace the 6F55. Do not expect that transmission to be any better because its a 8F35/8F40 transmission and rated even lower than the 6F55. It does the same shift lag behavior, and its not because Ford doesn't know how to tune a transmission properly. It is done on purpose.

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On 8/30/2019 at 12:41 PM, Zalvern said:

Unfortunately it is a normal part of the transmission behavior. All 6F series transmission vehicles will exhibit this at some point. Every vehicle I've driven with 6F35 and 6F55 (what the MKZ has now) is a sloppy mess if not cruising between 2nd and 3rd.

 

Firming it up with engine/transmission motor mounts and a tune by Livernois can help make it somewhat better, by becoming more aggressive. Though strict torque management and safety systems will still hold it back from displaying true power. While this has been a known flaw of behavior, proper fluid changes still should yield a healthy daily driver lifespan.

 

But the 6F family is old, and will never be refined for smooth performance. Therefore I am tired of settling for that transmission design flaw, and so no MKZ or Continental for me until a better one is made.

 

What do you recommend for fluid change intervals?  I put 260K on a Chrysler T&C minivan transmission with fluid changes at 40-60K, and it was good as new when I finally got rid of it.

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3 hours ago, MKZMark said:

 

What do you recommend for fluid change intervals?  I put 260K on a Chrysler T&C minivan transmission with fluid changes at 40-60K, and it was good as new when I finally got rid of it.

 

That's a good change interval range for the Ford 6F transmissions as well, or 1-2 year interval depending on drive style.

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