Bible 8hp70 transmission swap the world

This is super interesting. I built my new 4500 car around the 6L80 so good to know this might be an easy swap in the future. Could probably just use a spacer to keep the engine/tcase in the same spots. I could google this.. but any GM applications to bolt up to an LS?
 
75RamRunner said:
Here's my honest review feed back of this trans, i did use the sound german PCS controller and Russell is an awesome dude and extremely helpful, like on the phone Saturday night walking be through a pin error as I'm loading the rig on a trailer awesome.


I pulled a JY 8hp75 out of a 2019 ram 2500 (HP75 was used in 6.4 hemi trucks, 2019+ 1500s, and all 2500s) i could not stand the rotary dial so i pulled a T shifter out of a 2019 charger.

I used a custom adapter to stuff this trans behind a 440 big block, the first engine it was behind was roughly 500-520hp and 500-550 ft lbs of torque. I was using a MSD atomic EFI and had some analog inputs to the PCS to get it to shift right. I had the trans tuned via HPtuners by @dodgeboy and he did a killer job.

That version was the best version i had with this trans, it shifted in auto like needed to to (I'm on 43s) double overdrive was killer on the street with 5.38 gears and the low first gear was awesome on the trails. It held up the to rolling burnouts in 3rd gear, and beating on it on the rubicon. It did not like high angle off camber situations, both down and up. Think WH1 at fordyce, it would go into limp mode, im not sure if it was a pump design issue or what but as far as i know the jeeps with the 8 speed don't have this issue but i could get it to reoccur everytime.

I then blew up that engine, user error, and stuffed a 505" big block with 630hp and 700ftlbs in front of it. I swapped to a holley EFI setup at this time and used some of the digital inputs to the PCS. It did work, but never like i wanted it to. And it ended up limp moding me twice at fordyce pretty deep into the trail. From what me and russell could tell, even through the sine wave for the RPM was right from the Holley the PCS wasnt liking the signal and it kept seeing input shaft speed and no RPM signal and would error itself out. hence limp mode.

In the end i pulled it out and went back to a th400. I miss the low first gear a lot, and if this thing saw more street time i probably wouldnt have gone back, but for me it came down to working on it time vs trail time.

The 8hp is a killer trans, and is stout as ****. I'd recommend it to anyone but you need to be able to diag with a obd2 reader and understand controls logic. If your a carb over EFI guy id probably stay away from this swap.

This was with the 8speed

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As was this

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Thanks for sharing your experience, and awesome ride. That's very interesting that you narrowed it down to the Holley crank signal too. In fact I have to admit, Cleetus and those guys have crank signal loss issues so often with their Holley stuff, I wonder if there's something strange about how they handle, sensors, tone rings, or how their software handles the signal. Did you have one of those external tone rings and sensor mounts on/near the balancer?

broken4_racing said:
This is super interesting. I built my new 4500 car around the 6L80 so good to know this might be an easy swap in the future. Could probably just use a spacer to keep the engine/tcase in the same spots. I could google this.. but any GM applications to bolt up to an LS?
Click to expand...

No direct bolt up to LS stuff, but there are a handful of adapters in existence and some youtube videos of the swaps
 
broken4_racing said:
This is super interesting. I built my new 4500 car around the 6L80 so good to know this might be an easy swap in the future. Could probably just use a spacer to keep the engine/tcase in the same spots. I could google this.. but any GM applications to bolt up to an LS?
Click to expand...
billysspeedshop.com

GM Automatic Transmissions Compared: 4L65-E to 10L80-E for LS and LT Swaps

Complete comparison of GM automatic transmissions for LS and LT engine swaps. 4L60-E family, 4L80-E, 6L80-E, 8L90-E and 10L80-E specs, ratios, controller requirements and UK build advice.
billysspeedshop.com billysspeedshop.com

10L90 is the gm progression

Us shift makes a standalone ford 10r80 controller that claims it works with GM 10L90, same architecture

www.usshift.com

Quick 10 Clutch-to-Clutch Transmission Control

The Quick 10 controller allows the 10R80 Clutch-to-Clutch transmission to be implemented in a wide variety of vehicles, including ones not originally equipped with electronic control. It also allows customization of the transmission's behavior with an intuitive, user-friendly UI. The compact...
www.usshift.com www.usshift.com
 
AgitatedPancake said:
Great thread for sure! Those 6l80e's seemed pretty rad too, I was going to put one in a buggy I was building ~10 years ago, but never got around to finishing it up. These things seem to be the next level though. It wasn't until a week or two ago that I learned they should theoretically bolt to my engine, and I was sold instantly haha. I already had a transmission rebuild planned in the next year or so for the 545RFE, so it works out great.
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Have you driven one of these trannies yet? My wife has the 8HP50 in her JLUR....it's hands down the best auto transmission I've ever driven....and I've driven older PDKs. It's got a few quirks I don't love (reverse takes a LOT of throttle input to get moving and offroad it seems D works better than putting it in manual mode for some reason for climbing.....on descents, M works better).
 
Sean said:
Have you driven one of these trannies yet? My wife has the 8HP50 in her JLUR....it's hands down the best auto transmission I've ever driven....and I've driven older PDKs. It's got a few quirks I don't love (reverse takes a LOT of throttle input to get moving and offroad it seems D works better than putting it in manual mode for some reason for climbing.....on descents, M works better).
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I have some street miles in a WK2 with one and it felt great, but I've never actually properly put one through its paces offroad so that's great feedback. It'll be interesting to tinker with different tunes and see what I like

Speaking of - here's a short little video for the MaxxECU 8hp basics. Basically adjust some RPM vs throttle position tables to determine the shift strategy, and then a table for expected engine torque against the same RPM vs tps. They keep it pretty simple, but that's alright by me.

 
AgitatedPancake said:
Hybrid would be awesome to experiment with, I'm a big fan. I wonder if anyone has attempted to retrofit one of those yet
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According to the AI, nobody has successfully got the hybrid side working yet. Seems like the CAN bus/inverter control is tricky.
Ill probably check back in a couple of years and see if the aftermarket has caught up and the price of hybrid units has come down.
The most balls out version currently available has a 160kw/450nm E-motor. **** you'd barely even bother putting an ICE in front of that. The 8HP and it's converter/motor could just about be the whole drivetrain for an EV swap. It'd be tiny, and light.
But I digest.

I'm starting to get a few requests for driveshafts to suit this trans in swaps so it's getting around for sure. One customer has it setup in a drift car and dialled in for clutch kicks. Another has it in a Patrol with some big diesel in front and a squillion torques.
 
AgitatedPancake said:
Did you have one of those external tone rings and sensor mounts on/near the balancer?
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My RPM signal came from the CDI box that was part of the "Holley Ecosystem" i have their distributor, ignition box, and then sniper 2 tbi injection. The wiring diagram is super straight forward and my electrical analog rpm gauge has no drop offs that the eye can detect but doesn't mean it isn't dropping off.
 
andrew_ln65 said:
According to the AI, nobody has successfully got the hybrid side working yet. Seems like the CAN bus/inverter control is tricky.
Ill probably check back in a couple of years and see if the aftermarket has caught up and the price of hybrid units has come down.
The most balls out version currently available has a 160kw/450nm E-motor. **** you'd barely even bother putting an ICE in front of that. The 8HP and it's converter/motor could just about be the whole drivetrain for an EV swap. It'd be tiny, and light.
But I digest.

I'm starting to get a few requests for driveshafts to suit this trans in swaps so it's getting around for sure. One customer has it setup in a drift car and dialled in for clutch kicks. Another has it in a Patrol with some big diesel in front and a squillion torques.
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Yeah I could imagine it being a while before anything standalone came up for those. But to be honest, even them paired with that little 2.0 in the jeep 4xe platforms seems like a pretty potent combo. I wonder how much of the chassis you would have to carry over to make those systems happy

75RamRunner said:
My RPM signal came from the CDI box that was part of the "Holley Ecosystem" i have their distributor, ignition box, and then sniper 2 tbi injection. The wiring diagram is super straight forward and my electrical analog rpm gauge has no drop offs that the eye can detect but doesn't mean it isn't dropping off.
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That seems like a more reliable source than some of those generic aftermarket external sensors, so probably not the same thing. But interesting either way!
 
Next topic - cooling. From the skimming I’ve been doing I’ve gathered a few things. First, it seems to be worth running a thermostat like stock to get them up to temp in their happy place (but always debated). Next, apparently they flow some fluid, so you should go -8an for the whole system, meaning no -6an cooler and hose. Then, it seems like they can generate some heat so give them some good cooling.

If you get the ram version, the cooler ports are unthreaded smooth bores with a ~0.657” bore. Some companies make some bolt on thread adapters that maintain that oring configuration, but I decided I’m going to tap mine for 3/4-16 threads (calls for a .6875 drill size), and install -8an right angle ORB fittings.

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Then I grabbed a Derale 25719 180 drgree fluid thermostat with 1/2 NPT threads all around. I was figuring it was going to end up on the chassis somewhere, but by some miracle the spacing between ports is ~1.50”, and the fluid ports on the transmission are so close to that, I think I’m going to be able to bolt the thermostat directly to the fittings coming out of the ports. Packaging win, and it’ll still be narrower in the tunnel than my 545RFE

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And the cooler itself will obviously be different for everyone, but I found one for a ~2014 silverado 2500 that is around 28” wide, 6” core height, and 10an orb ports (after removing the quick connect fittings). It’s around 1.25” thick, and pretty reasonably priced. I’m using -8an ptfe line everywhere for it. No idea how this package will work yet, but I think it’ll be ok.

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O-ring boss fittings use a counter bore in the female hole to keep the o-ring from squeezing out. Maybe you know that but just drilling to 11/16" and tapping 3/4 may not work very well. As a DIY option in this scenario, I'd personally tap those holes to NPT. You might get away with the o-ring boss fittings if you put a large chamfer in those holes with a countersink?
 
DesertCJ said:
O-ring boss fittings use a counter bore in the female hole to keep the o-ring from squeezing out. Maybe you know that but just drilling to 11/16" and tapping 3/4 may not work very well. As a DIY option in this scenario, I'd personally tap those holes to NPT. You might get away with the o-ring boss fittings if you put a large chamfer in those holes with a countersink?
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Light countersink after threading is the plan, in the worst case I could use some of those bonded sealing washers but I don't think they'll be necessary. I considered NPT early, but if I did 90*s, I'm not sure the second one would have the swing clearance from the first to tighten where the ORBs are swivels. and a straight fitting plus separate 90 would stick out a bit further than desired, so this seemed like a good fit.

I did also make a quick little 3d printed jig to help true the taps as I get them started, so the orings get compressed evenly

8HP70 cooler jig.JPG


IMG_2636.jpeg
 
DesertCJ said:
O-ring boss fittings use a counter bore in the female hole to keep the o-ring from squeezing out. Maybe you know that but just drilling to 11/16" and tapping 3/4 may not work very well. As a DIY option in this scenario, I'd personally tap those holes to NPT. You might get away with the o-ring boss fittings if you put a large chamfer in those holes with a countersink?
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Throw the O-ring in the trash and use a dowty washer. No counter bore needed.
 
Sean said:
Are dowty washers/bonded seals better than ORB fittings (provided you have the counterbore)?
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Dowty washers are marginally worse in every way except cost/complexity but for automotive stuff and "normal" hydraulics you're not really running into pressures where that matters. Do whatever is easier for your situation.
 
I could go straight to the dowty bonded washers, from what I've seen they work pretty well. But I already have the countersink so I'll just send it and report back

Also here’s the final fitting stackup plan. The male fittings in the thermostat in the above pics were replaced with female, connected directly to the ORBs. It’ll be super tight to the nut on that manual park release lever when the ORBs are tightened, but I think it will clear.

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Does the Dodge 8hp bolt up to a GM 241 transfer case?
 
DMG said:
Does the Dodge 8hp bolt up to a GM 241 transfer case?
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Bolt pattern yes, but the 8hp70 output shaft is 23 spline where I believe most GM cases need 27 or 32 spline. EDIT - bolt pattern clocking is a bit different on those chevy cases as well I believe

In fact just today I got myself a 23 spline JK regular 2.72:1 nv241 that I plan to run. I went this route because it has fixed yokes front and rear, and is cheaper than a proper SYE for my current NV242HD lol. I just checked its fitment, all good:

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Also I figured this might be handy for someone out there - the output ends essentially right at the transfer case mounting face. It’s proud by a little sliver, but that probably doesn’t matter too much. At least it’s not another random output length adding to the like 4-5 others that were used over the decades.

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EDIT - first, I capped the ports with silicone plugs. Important step lol

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Put my little 3d printed fixture on and drilled it out the remaining ~30 thou to .6875

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Then used the fixture for its main purpose, 3/4-16 tapping for -8an ORB fittings. The tap lightly cut into the plastic, so the tap was fully supported when it started into aluminum:

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Also worth noting I went with a machine tap because it has much less taper than hand taps and these ports aren’t very deep

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Giggity:

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I haven’t chamfered it yet so I just took the orings off for testing, but the packaging turned out excellent. It clears the manual park release lever, and aaaalmost rests on that rear boss that will go unused

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Right here I’ll use that upper (left) boss to add a support bracket to 2 of the 4 mount holes on the thermostat:

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Then the lines are either going to have 2 45*s, or a 90 and a 45, and loop up over the transmission to run up the passenger side frame rail. That way they don’t interfere with the steering box or any of the steering lines.

Also a cool note, because one side of the thermostat is male 8an, and the other is female 8an, I could theoretically unhook the lines and just delete the thermostat on the trail and keep on going if it ever causes any issues in the future.

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AgitatedPancake said:
I haven’t chamfered it yet so I just took the orings off for testing, but the packaging turned out excellent. It clears the manual park release lever, and aaaalmost rests on that rear boss that will go unused
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are you going to covert the t-stat housing to orb?
 
JohnnyJ said:
Awesome thread. Most info I’ve seen is drag race or street car, not much on 4x4s.
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Hell yeah. So far things are looking pretty good for our uses in the offroad world. A little wary of RamRunners experiences, but we'll see if I encounter any of the same issues. Not that I'll be wheeling this jeep as hard as his rig, but if this one goes well I might do another one of these for my big jeep


mobil1syn said:
are you going to covert the t-stat housing to orb?
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Nah. It would be cool if they were ORB, but I'm not going to get new taps and adapters just to swap 'em out
 
Following closely for swapping the 6.0 LQ4 I fell into for my rig. I don't currently have a trans, I had been loosely planning a th400 or 4l80, but looking at pricing this might be the better route and give a better gear spread, if it works well for our application. Another bonus is that it won't need a tcase adapter to bolt to my current tcase.

I really like the 8hp in my daily driver 2.0 JL Rubicon, only thing I'd like to change is adding paddle shifters from a 392, sometimes in low range it's slow to downshift when you want it to.
 
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