Trans swap 6R80(A6) to 4r70 or C4

[2005mach1]

I have searched and read all the trans swap threads here and 2005-2010 section.

I want to swap from a 6 speed automatic (6R80) to a 4r70 or C4.
Will I need a new pcm/computer?

any help/info would be great

 

[r.barn]

How important is a working speedo to you ?
the shift parameters are big part of the ECU too.

With a manual valve body it wont be problem but I doubt you would ever get the speedo to work.

 

[timfoster405]

Are you having problems with the A6? I have seen a few guys here go low 9s on stock tranny.

 

[tjm73]

Why on Earth would you want to do this? The 6R80 is Ford's best automatic yet.

 

[2005mach1]

Are you having problems with the A6? I have seen a few guys here go low 9s on stock tranny.

Yes and NO

I ran mine with the cooler lines plugged and smoked it. cheaper to go c4 then to fix it.

The 6R80 is a bad ass trans drove 500 miles with no fluid flow

 

[kdanner]

I've thought about this a lot. The 6R80 is a great trans except the ratios suck. If I was going to swap to something else it would be a 4L80E. Turbo 400 based with overdrive and lockup. They make things for them like controllers and even transbrakes. Modular bellhousing which takes the place of the SFI flexplate shield and also rigid SFI trans shields are available for them too.

 

[chuck@evoperform]

The 6r80 is a phenomenal tranny. Chris Cruz's 11 GT/CS went 8.99 with the factory automatic with just the exedy stage 2 upgrades with the stock tranny cooler..........

 

[2005mach1]

The 6r80 is a phenomenal tranny. Chris Cruz's 11 GT/CS went 8.99 with the factory automatic with just the exedy stage 2 upgrades with the stock tranny cooler..........

yes it is --- thanks Chuck

 

[Bmr4life]

I've thought about this a lot. The 6R80 is a great trans except the ratios suck. If I was going to swap to something else it would be a 4L80E. Turbo 400 based with overdrive and lockup. They make things for them like controllers and even transbrakes. Modular bellhousing which takes the place of the SFI flexplate shield and also rigid SFI trans shields are available for them too.

I love everything about the trans expect 6th gear. Its just not low enough.

 

[Bud]

I love everything about the 6r80 except its lack of available safety equipment. It sure does make a nice street trans that holds up to 10 second blasts with no work though.

are the 4r70 or c4 any lighter?

 

[Steel City]

I have searched and read all the trans swap threads here and 2005-2010 section.

I want to swap from a 6 speed automatic (6R80) to a 4r70 or C4.
Will I need a new pcm/computer?

any help/info would be great

Your OEM transmission is your best option, fix it. The 2 choices you mentioned are junk, even when "built".

 

[kdanner]

I love everything about the trans expect 6th gear. Its just not low enough.

Not having a 1:1 gear is horrible from an efficiency standpoint. I'm stuck trapping in a non 1:1 gear.

Then there's the 4.17 1st. Put enough gear in the car to trap in the 1.14 4th and it shifts before 60', making traction management tough. The alternative is to not run much gear and trap in 3rd, this makes the traction really easy to manage but the car is now soft down low due to lack of gear. Then no matter what gear is in the rear, there's a huge ratio split on the 1-2, upshifting to that 2.34 2nd is a massive RPM drop. If someone came up with some planetaries with decent ratios it should be a good bit quicker.

Everything else about it is great. It's well proven to take a beating at this point, and it is also very compact and lightweight for a 6 speed trans. We do really need a rigid trans shield instead of having to hassle with a blanket, and also an SFI bellhousing that can replace the stock one so we don't have to fight the tight space with an external flexplate shield.

 

[Grabber Blue 5.0]

Then no matter what gear is in the rear, there's a huge ratio split on the 1-2, upshifting to that 2.34 2nd is a massive RPM drop. If someone came up with some planetaries with decent ratios it should be a good bit quicker.

This is what's troubling to me, too big of a difference between 1st and 2nd gear.