Jezza's Ford 6R80 Transmission Swap

Broken right at the radius. Might be time for some RCVs.

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Pretty sure this is an anomaly, RCVs won't really add anything here (stub to flange).

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Pretty sure this is an anomaly, RCVs won't really add anything here (stub to flange).

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I don't like anomalys. When I called Currie to get a replacement I asked what was included in the HP 44. They are assembled with a cromoly upgraded shaft set according to Currie. I asked them what I could do that would be stronger and they suggested RCV so I donno.
 
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I don't like anomalys. When I called Currie to get a replacement I asked what was included in the HP 44. They are assembled with a cromoly upgraded shaft set according to Currie. I asked them what I could do that would be stronger and they suggested RCV so I donno.

One end (flat side) hugs the unit bearing the other is bolted to it preloading the bearing itself. The shaft is so short there's nearly no deflection that should be possible. I'm thinking the torque might have not been correct, as a stub shaft breaking is rare in my experience.

RCV should really only play a part when you're turning as a u-joint isn't as strong under those use cases.
 
I had it torqued to 175 ft/lb. Maybe that's not correct. I don't remember where I read that.
 
Update. I got the wiring all run for the reverse lights, neutral safety, trans brake and paddle shifters. It all works flawlessly besides the paddle shifters which I don't have switches for yet. The trans brake is a bit underwhelming as the stall is low and doesn't flare high enough to make power. The PCM codes have gone away for the most part. No check engine light, but there is a P0750 code for the missing 42RLE solenoid pack. I have a plan for that, but if that doesn't work, I can always do a manual trans computer. Also, it is worth noting that I have been running successfully with an aftermarket hall sensor for my crank pickup. The factory PCM doesn't seem to know or care about the sensor. I have had no issues with drivability or codes in the PCM relating to the crank sensor.
 
That is awesome you go your 6r80 working in your TJ. I had so many issues with mine, though I could never figure out what was causing the issues. Glad to see it working!
 
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That is awesome you go your 6r80 working in your TJ. I had so many issues with mine, though I could never figure out what was causing the issues. Glad to see it working!

I was nervous a bit after reading your story, but it has been great. I played with the settings a bit in the Shiftware software and got it dialed in where I like it. Full throttle blast it shifts right at 5000 where I set it. I wonder if you were having problems with one of the internal sensors on the lead frame.
 
One end (flat side) hugs the unit bearing the other is bolted to it preloading the bearing itself. The shaft is so short there's nearly no deflection that should be possible. I'm thinking the torque might have not been correct, as a stub shaft breaking is rare in my experience.

RCV should really only play a part when you're turning as a u-joint isn't as strong under those use cases.

Not exactly in the same spot, but the same failure mode (not brittle). These are G10 Chromolly shafts. They are not very hard...I rockwell tested them just to know. I don't remember the exact value, but it was high 30's IIRC. I know its only two examples, but they CAN break in the stub area. Mine was torqued properly too.

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Not exactly in the same spot, but the same failure mode (not brittle). These are G10 Chromolly shafts. They are not very hard...I rockwell tested them just to know. I don't remember the exact value, but it was high 30's IIRC. I know its only two examples, but they CAN break in the stub area. Mine was torqued properly too.

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Wow, that's a clean break. I know there is an argument that when torqued it is a bolted assembly under tension, and that breaking the shaft shouldn't happen if it is properly torqued. I think that is probably true to a point, but I also think that torque can overpower that friction at some point and cause a failure. My crawl ratio in low is 82:1 and with 35's I think I broke that friction bond.
 
Mine broke when my pinion bearing seized (at 50 mph). The only way for the 35's to keep rolling was to pop the axle and I thought it was interesting that it broke there, vs the long side. It only twisted the splines a few degrees before breaking too.

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I replaced the torque converter today with a unit from Circle D. This is the 245mm Pro Series with a 3000 stall. However, because the Jeep is light and the engine makes lower torque than a Ford mod motor it stalls around 2500. Makes driving it much nicer and it's not pushing through the brakes at idle anymore. I was able to swap it in a couple hours leaving the trans and transfer all connected.









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I replaced the torque converter today with a unit from Circle D. This is the 245mm Pro Series with a 3000 stall. However, because the Jeep is light and the engine makes lower torque than a Ford mod motor it stalls around 2500. Makes driving it much nicer and it's not pushing through the brakes at idle anymore. I was able to swap it in a couple hours leaving the trans and transfer all connected.









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Nice. This sounds like it's working out to be a good deal. Any plans to offer a kit?
 
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I could, but doubtful I would sell many. Between the trans, Atlas, driveshafts, adapters, controller and now converter it's probably a $8-10k project. There are corners that could be cut, but it's not as easy or cheap as a 32rh.
 
Update. I have been enjoying the crap out of the stall converter. It seems to stall just at if not a few hundred rpm higher than the 42RLE stock. I also set up the converter clutch to activate in 5th and 6th. Essentially giving it 2 more gears. The converter clutch kills almost 800 rpm when it locks up. Next up I am going to mess with the off-road functions of the converter clutch. It has a lock up function in 1st and 2nd that can be locked when descending a steep grade. It essentially turns an auto into a manual for engine braking.
 
Update. I have been enjoying the crap out of the stall converter. It seems to stall just at if not a few hundred rpm higher than the 42RLE stock. I also set up the converter clutch to activate in 5th and 6th. Essentially giving it 2 more gears. The converter clutch kills almost 800 rpm when it locks up. Next up I am going to mess with the off-road functions of the converter clutch. It has a lock up function in 1st and 2nd that can be locked when descending a steep grade. It essentially turns an auto into a manual for engine braking.

This is such a cool thread. WAY beyond my ability, but I love to see guys pushing the envelope. Sounds like a great transmission for our Jeeps, especially if you can lock it up in first and second. I'm in the process of swapping in an 42RLE to replace my NV3550. Hill descents are my biggest concern going to an auto. With the 4:1 T-case and a manual, it was REALLY easy to control my speed down hill...now, with an auto, I'll need to rely on brakes...and we all know how good those are!
 
This is such a cool thread. WAY beyond my ability, but I love to see guys pushing the envelope. Sounds like a great transmission for our Jeeps, especially if you can lock it up in first and second. I'm in the process of swapping in an 42RLE to replace my NV3550. Hill descents are my biggest concern going to an auto. With the 4:1 T-case and a manual, it was REALLY easy to control my speed down hill...now, with an auto, I'll need to rely on brakes...and we all know how good those are!

Thanks, I'm just glad it works. I am trying to get all the details worked out before wheeling season. I hope it performs well on the trails and in the rocks. I have wheeled the TJ with the 3550 and a 231. It was a handful. Much better with a hand throttle, but still hard to control especially when at high angles and crossed up. The LJ had the 42RLE, and I was actually impressed with how it drove. I don't have a lot of positive experience with Chrysler transmissions, but that 42 did well.
 
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Let me start by mentioning again that I am not a good videographer, in fact I am crap. I have shaky hands and no creative eye. I just thought I would share this 4x4 transbrake launch video, as it was pretty intense. I was trying to hold the phone and run the switch at the same time, and when it took off it dang near scared the soul out of me. Enjoy.

 
Your work is amazing, it's almost art. I was looking at that flywheel spacer thingy and thinking it'd make a good wheel lol. Love how stoked you sound on the first video of it running!

Thanks for explaining the "manual like engine braking" on this last page I was saving asking about it since the first post lmao. Killer work man
 
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