[Plague]

First off I’m just spit balling idea at the moment so nothing is serious. But I’ve been wondering this for some time.

If any of y’all would do a transmission swap on your truck, would you do something like a T56, a 6R80, or something else altogether?

 

[Dusten]

First off I’m just spit balling idea at the moment so nothing is serious. But I’ve been wondering this for some time.

If any of y’all would do a transmission swap on your truck, would you do something like a T56, a 6R80, or something else altogether?

There's a whole section dedicated to the 6 speed manual

The 6r80 is becoming a popular idea. No one has shown any gains yet. It also requires a gear swap to 3.08 or 3.27s to make first gear usable. With those gears 6th gear will have lower rpms than the 4r100, with stock gears they have nearly identical overdrives
Several members have stated that to low of a freeway rpm causes some serious issues with lugging and needing to downshift. This was with the t56 swap. But same concept.

 

[Mike_L]

I’d go all in. Coyote or 3.5EB and 10 speed. That way you just take everything out of the donor and swap it. Harness is there, computer is there, pedal is there, fuse boxes are there and everything is matched and knows what everything else is doing.
In this computerized world, when you start mixing and matching, things don’t get along and cause problems.

 

[Dusten]

the 6r80 is easy to swap with the quick6 controller. A coyote/10r swap isn't as easy as it sounds.

 

[DVC]

This is a discussion I'd like to see more of, as well as really nicely done "How To".

I'm not too considered with gains at the strip, as much as enhanced driveability on the street. Tighter splits and a more modern feel. It would have been nice if the 6r80 would drop our revs on the freeway without changing the final drive, but that's not too bad. It could also be cool having different shift programs with the Quick 6.

 

[Dusten]

This is a discussion I'd like to see more of, as well as really nicely done "How To".

I'm not too considered with gains at the strip, as much as enhanced driveability on the street. Tighter splits and a more modern feel. It would have been nice if the 6r80 would drop our revs on the freeway without changing the final drive, but that's not too bad. It could also be cool having different shift programs with the Quick 6.

Look at the torque curve of the lightning.
I'm not sure the splits are an issue
Someone's posted most of a how-to on Facebook.

Here is a visual of the differences between the transmission

This is a 6r80 with stock gears and tires. Its showing speed at 5800 rpm shift points, and the rpm the engine will drop to in the next gear.
First gear is very aggressive
With this setup in overdrive you are at 2300 rpm at 75 mph

Here is the 6r80 with 3.08s
You are at 1900 rpm at 75mph
From the older 6 speed threads, both cody and kyle complained about lugging these motors with the tall overdrive of the viper 6 speed. The viper T56 with stock 3.73s puts the engine at 1675 at 75mph

Here is the stock 4r100 and stock gears
2350 rpm is 75mph

 

[Dusten]

Youve gotta remember the 6r and the 10r are designed for a motor that makes peaky, high rpm power.
The 5.4 in our trucks has a torque curve that's flat.

 

[Dusten]

For fun here is a comparison of the t56 I'll be running
2100 rpm at 65 with stock gears

 

[DVC]

These are great charts!

I wonder if the "lugging" issue can be tuned out, why it doesn't happen with the 4r100 at 40-50 MPH. You've gotta remember when you're on the street, you spend the majority of the time at part-throttle. Closer ratios absolutely are an improvement when you're not at WOT.

 

[Dusten]

These are great charts!

I wonder if the "lugging" issue can be tuned out, why it doesn't happen with the 4r100 at 40-50 MPH. You've gotta remember when you're on the street, you spend the majority of the time at part-throttle. Closer ratios absolutely are an improvement when you're not at WOT.

AT 40-50 my trucks in third gear, so it doesn't lug. It doesn't shift into overdrive until 48-50mph.
You can't tune out lugging in overdrive unless the fix is to have the truck downshift at the slightest touch of the throttle.

I have a 10 speed mustang. Even with 10 gears that car will still hold the wrong gear, upshift early and lug itself.

Its less about the number of gears available, and more about the programmed shift strategy.

 

[1qwktrk]

These are great charts!

I wonder if the "lugging" issue can be tuned out, why it doesn't happen with the 4r100 at 40-50 MPH. You've gotta remember when you're on the street, you spend the majority of the time at part-throttle. Closer ratios absolutely are an improvement when you're not at WOT.

not really, engine just isnt making efficient torque at that low rpm. lugging at 40-50 is far less load than lugging at 65-75 drag coefficient more than doubles. Unless you want to be way into the throttle and in boost at low rpm its miserable at 1600 rpm and trying to maintain 65-70 cruising if the road is anything but perfectly flat.
6th in my t56 with a .50 od was useless unless i was doing 80-85 with 3.73's and 305/45/18 tires.
with 4.10's not its still a bit tall but manageable. though 4.10's made 1st-2nd pretty much worthless on the street. great fun but no street tire holding it together. 3rd tops out about 100mph after it finally stops spinning up to about 55-70mph.
I do think a 6r80 with 3.55's will be fine though. you get a great gear spread, with a violent first gear that would be great running a 30" slick and still an improvement in OD over the 4r100. But transmission shift schedule would be very important for good driveability.
Dusten, I would argue using that chart for shift schedule comparison on 6r80 with stock redline/shift point is silly. no one likely using stock shift points whos into that kind of trans swap. 6-6300more likely.
Only reason i shift at 6200 is i dont trust valvetrain much more, but it was still making power up there...If i ever get some time to invest in the truck again it may get spun much higher.

 

[Dusten]

not really, engine just isnt making efficient torque at that low rpm. lugging at 40-50 is far less load than lugging at 65-75 drag coefficient more than doubles. Unless you want to be way into the throttle and in boost at low rpm its miserable at 1600 rpm and trying to maintain 65-70 cruising if the road is anything but perfectly flat.
6th in my t56 with a .50 od was useless unless i was doing 80-85 with 3.73's and 305/45/18 tires.
with 4.10's not its still a bit tall but manageable. though 4.10's made 1st-2nd pretty much worthless on the street. great fun but no street tire holding it together. 3rd tops out about 100mph after it finally stops spinning up to about 55-70mph.
I do think a 6r80 with 3.55's will be fine though. you get a great gear spread, with a violent first gear that would be great running a 30" slick and still an improvement in OD over the 4r100. But transmission shift schedule would be very important for good driveability.
Dusten, I would argue using that chart for shift schedule comparison on 6r80 with stock redline/shift point is silly. no one likely using stock shift points whos into that kind of trans swap. 6-6300more likely.
Only reason i shift at 6200 is i dont trust valvetrain much more, but it was still making power up there...If i ever get some time to invest in the truck again it may get spun much higher.

Stock is 5200
My truck shifts between 5800-6000 so I used that.