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Discussion Starter #1
I've decided to go another route on my 07 expedition. I've been rolling with a m5r2 trans for the last 5 years and 35k miles and something in the clutch system is not good. I also haven't been able to get 4x4, or cruise control working. So its time to change it up. I'm going with a 6r80 trans which is quite proven in the gasser world. So I have a few questions, I doubt the trans has been put behind a 4bt yet. Ill be machining the adapter plate myself. My current power is probably 225hp...assuming 450tq. The trans is easily rated for this from the 5.4.

Should I use a stock converter to get a baseline for how it will run? Will a stock HD flexplate be good for this application? Will a 5.4 starter start a 4bt?

Trans will be tuned with hp tuner.

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I make the adapter for a 6r80 to mate behind a Kubota v2203.

Us shift make a controller for the 6r80 and currently beta testing a 10r80 controller.


I want to build a v2203/10r80 and swap into a jku.

I am following.

Find someone to build you a low stall converter. The stock gas unit is to high.

There is an aftermarket gear reduction mini starter available for the 6r80
 

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Converter needs to be taylored to torque curve of 4bt, not gasser. Needs to be able to provide adequate operating system pressure at that RPM, otherwise will not clamp bands properly and will fail.

Ed in Co.
 

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The 6R80 has a maximum torque input of 590 lb ft. so it would handle the torque. Main issue might be finding a torque converter compatible with a 4bt. Destroked probably already had an adapter plate that should work and may have a flex plate as well. Their adapters use the Ford 6.0 diesel starter. You'd need to check with them on that. That transmission comes mated to small diesels in the Ranger truck line but doubt those have torque peaks the same as Cummins 4bt.
 

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Discussion Starter #5
Ok. Thanks guys. I'll be sure to get a proper stall speed on whatever converter I go with. Ill be calling destroked tomorrow to see if they have an adapter plate for this, I prefer to machine my own parts, so if I buy my own adapter it'll feel like sacrilege.....but time is important for this build. Did some research, and it looks like the target stall for the 4bt is approximately 1400-1600 ish rpm?

Detroked flex plates are really expensive, this I think ill make myself.

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Discussion Starter #6
Just spoke with destroked and the woman I talked to claimed they don't make an adapter for the 6r80, but not going to lie she didn't sound very educated on transmission adaptes when that is what they speciality in.

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On the stall speed for a torque converter, most guys shoot for 1300 RPM. Full torque for a 4bt come on around 1700-1800 RPM.
 
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