Let us know who you purchase the china "Tech II" from, friend of mine has one and so far so good. While looking for one I perused Alibaba, the amount of companies making them is crazy, some are good the rest are just junk...
NP246/266 custom build
- Thread starter chrisuns
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Let us know who you purchase the china "Tech II" from, friend of mine has one and so far so good. While looking for one I perused Alibaba, the amount of companies making them is crazy, some are good the rest are just junk...
Yep, it monitors for a 15 RPM (I believe it is 15 RPM) difference between the front and rear prop shaft, and it also monitors throttle and speed inputs; Above 25mph, the TCCM will automatically bias more torque to the front. Now, at what % throttle does more biasing start, I don't know - one of the reasons I want a Tech II because the literature is vague on the full programming of the TCCM.
Originally, I went with synthetic since it handles heat a little better while I'm driving without a cooler, that and I am using transmission clutches. I also had concerns of the autotrak being so highly friction modified, it would reduce clutch holding ability.
So after a little more research, I've picked up some autotrak2 and intend on trying that today - as I understand it, is in fact synthetic too and if it drives better with it win win I guess.
But frankly, I wanted to see how it acted with an ATF, I aint scared :woott:
Here's a few photos of the Clutches (pic1), the clutch assembly and mainshaft (pic2), the encoder (pic3) the apply lever (pic4) and the shift-cam (pic5).
The electric motor is a braked variant of the Globe 409A587 that is rated at 3200oz-in. stall torque @21.58amps (roughly 16.67 ft lbs), that goes throw a 1:3 gear, then a 1:2.6 gear (pic3)- IIRC, (I've forgot the exact gear count on all the teeth). This brings the encoder torque to the shift cam(pic5) at roughly 130FT.LBS - assuming 100% efficiency though the gearing, which we all know it is not; likely, around 100-110FT.LBS. after losses.
The cam gear is where the torque is transferred to linear force and multiplied and then again multiplied by the apply lever{it acts as a fulcrum(pic4)}.
If memory serves, the lever is a 2.5 ratio and the shift cam was VERY difficult from me to find of the ratio and I know I'm not right on that 100%. That requires several factors such as the rolling resistance of the lever roller, the motor RPM; fluid viscosity etc..
Let's just say I gave up after half of a legal notepad worth of math on this specific part. I'm not being giving when I say it's at least a 8 ratio, so a minimum of 2000 lbs of apply force on the clutches. I suspect it's more around 3000-3500 lbs though.
Especially, giving in to the idea the clutch apply has more than enough force to damage the machined bearing surface of the rear case (magnesium) - I am more than curious about this, so I will revisit the numbers on this to be specific; I just got tired of several hours of looking into my engineer books and math.
But the force is transfered from the encoder-shift cam-apply lever-then to the apply plate(pic2); which in turn causes the clutches to bite into the steels which are indexed into the clutch drum - which is connected to the chain sprocket and front output shaft via the chain.
But that's the 101 on how the clutches receive force.
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Ehh, I had no idea where I was going to get one, lol! Likely Alibaba though, I plan to google about that tonight. Any recommendations?
if i were you to keep things consistant and good data, i wouldnt change a damn thing till after your 2k mark. you may not know what hurt the clutches or let them live by swapping fluid 500 miles in.
this is really cool! i know a few trucks this would be perfect in
No, gave up and just borrow my friends for the time being till I find a good US supplier that has a good track record with one of them "Alibaba companies." What I do know about Alibaba and the companies on there they range from real crap units to good quality units same goes for the manufacturing facilities from junk to rivaling some of the best in the US...
To date I have not bricked my BCM as some of these off brands have been known to do. So far I have bled/cycled the ABS controller which surprisingly reset something in the transmission, found the BCM code for my driver mirror still need to install/program the autofold smaller mirrors I have in the garage..
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Update: I ended up having to pull the transfer case! I noticed the fluid was running a bit low. Well, I checked it every 100 miles, so I knew there was no external leaks - Turned out to be the input gear leaking fluid into the transmission :spit: Luckily, I didn't put autotrac fluid in it; this was one of my reasons not to, btw.
The Fix: short-term solution was to add a larger diameter freeze plug + JB weld (I've spent enough, so custom solutions will wait until I feel 100%)
If the unit proves reliable, I've always had a cad of a permanent solution (A cnc'd plug that will house a new bearing).
Also, got hit with some luck from this too - one of the clutches jumped up the splines and the encoder crushed the clutch's teeth! I considered this a possibility during assembly, as it was something I missed prior to cutting the apply plate (I expected the apply lever would take up the slack; however, I just missed the mark). The apply plate in original form rides down far enough in 2wd to not allow the clutches to ride up on the hub, mine is modified and only prevented this during Auto, 4High/Low.
The fix: More prudent measurements, then I used a 360 degree snap-ring to give me the extra bit I needed to prevent this. I'll be ordering a new Apply plate and will cut down 2 MM on the apply plate and 1.15mm on the Hub vs 3.15 on the apply plate - that'll keep the clutch teeth 100% engaged on the splines without resorting to "rigging" with a snap-ring.
The pictures confirms the motor put a large amount of force on the clutches. I was kind happy when I saw that, lol.
But that's the 100% thus far, I still love it. Sucked putting it back in, as I dropped it on my fore-arm from the torsion bar cross member - this one weighs around 110-115lbs
The Fix: short-term solution was to add a larger diameter freeze plug + JB weld (I've spent enough, so custom solutions will wait until I feel 100%)
If the unit proves reliable, I've always had a cad of a permanent solution (A cnc'd plug that will house a new bearing).Also, got hit with some luck from this too - one of the clutches jumped up the splines and the encoder crushed the clutch's teeth! I considered this a possibility during assembly, as it was something I missed prior to cutting the apply plate (I expected the apply lever would take up the slack; however, I just missed the mark). The apply plate in original form rides down far enough in 2wd to not allow the clutches to ride up on the hub, mine is modified and only prevented this during Auto, 4High/Low.
The fix: More prudent measurements, then I used a 360 degree snap-ring to give me the extra bit I needed to prevent this. I'll be ordering a new Apply plate and will cut down 2 MM on the apply plate and 1.15mm on the Hub vs 3.15 on the apply plate - that'll keep the clutch teeth 100% engaged on the splines without resorting to "rigging" with a snap-ring.
The pictures confirms the motor put a large amount of force on the clutches. I was kind happy when I saw that, lol.
But that's the 100% thus far, I still love it. Sucked putting it back in, as I dropped it on my fore-arm from the torsion bar cross member - this one weighs around 110-115lbs
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Also clutches measure new and steels looked perfect with 1k miles of ABUSIVE driving in auto. I'm unfortunately driving like a 16 year old again when no one is around :rofl:
Probably launched it 20+times from 10-20lbs in auto :roflmao:
The Cognito centerlink is awesome too for those on the fence, IIRC it's $664 on ebay shipped! A few photos of it and tie-rod measurements vs stock. I had no idea how flimsy the stocks centerlink was until I stood on it and it flexed :woott: ... I weigh 160 lbs.. Pathetic!
Probably launched it 20+times from 10-20lbs in auto :roflmao:
The Cognito centerlink is awesome too for those on the fence, IIRC it's $664 on ebay shipped! A few photos of it and tie-rod measurements vs stock. I had no idea how flimsy the stocks centerlink was until I stood on it and it flexed :woott: ... I weigh 160 lbs.. Pathetic!
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Awesome thread Chris! Ive gotten a huge kick out of following it.
Very cool, badass work on figuring all of this stuff out and making the custom parts to fit extra clutches etc.
Also good to see that the clutches are holding up and the encoder motor is doing its job properly.
Very cool, badass work on figuring all of this stuff out and making the custom parts to fit extra clutches etc.
Also good to see that the clutches are holding up and the encoder motor is doing its job properly.
That is a really cool idea, thanks for sharing all your progress!
When you are done, do you plan on releasing the measurements used to machine things out, so we could make our own? My brother is swapping a Duramax into a quadrasteer pickup with the NP246 case, and we are interested in doing this.
Or is your long term plan to sell cases pre-modified?
When you are done, do you plan on releasing the measurements used to machine things out, so we could make our own? My brother is swapping a Duramax into a quadrasteer pickup with the NP246 case, and we are interested in doing this.
Or is your long term plan to sell cases pre-modified?
The measurements are custom to each individual clutch assembly. I measured the clutch stack with the Kent Moore J-44295 (clutch shimming tool), then used various gauges and spacers to determine what amount to machine from the apply plate. The spec is 2.16mm +-0.10mm of clearance on 03+ np246, measured on the tool.
I really haven't thought too far into that. However, it is unlikely I would ever sell them, just because I wouldn't have the time to fully dedicate to tech calls etc..
The wiring systems alone makes it difficult for the average person to install, we're talking repining, adding wires and making custom harnesses that has more wires than a LB7 to LBZ swap - which I really haven't documented on here, yet.
A GM tech could diagnose the electric side of the 246 system on my truck, as I'm pretty much OEM colored wires and harness - That involves removal of the main UBEC harness that runs into the cab by the driver side hood-hinge.
You could technically cheat and make a direct harness from the TCCM to the transfer case or buy the OEM harness for $130, but you'd still have to wire from the TCCM connectors to UBEC.
The big part is I don't think a lot of people would want to spend the $ for something like this, as not a lot of people like the 246s. I'd have to tally it up but I'm in roughly 1k, unless I sell my old 263 after I rebuild it.
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Thanks Ben! It's been some work, that's for sure! However, I just grin when it kicks in and sucks down on the curves!
I'm thinking finish my intellibeam next, install this G6 panoramic sunroof (buying the entire roof off a G6, then going to create a support that incorporates the A,B and C pillars; as not to reduce roof strength in a roll-over); then start up the stabilitrac project I've been hounding you about the last 2 years! :roflmao:
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Waaaaaaait a second.....intellibeam? Panoramic sunroof? Ok Chris, spill the beans!!!!
I havent seen ideas like these since Ben figured Stabilitrak out and before that the LUX threads....keep up the great work.
I havent seen ideas like these since Ben figured Stabilitrak out and before that the LUX threads....keep up the great work.
In our case, we are swapping a Duramax into a gas truck that already has the 246. I'm an electrical engineer, and while I haven't messed with the wiring as much as Ben (or even you from what I've seen), I know my way around it enough to figure that part out on my own. It is the mechanical upgrades that are beyond my skill set, so I have been watching this with great interest.
Yeah, sounds like you have some cool stuff going on! Keep us posted! I've always been envious of Ben's Stabilitrak install on his Duramax.Waaaaaaait a second.....intellibeam? Panoramic sunroof? Ok Chris, spill the beans!!!!
I havent seen ideas like these since Ben figured Stabilitrak out and before that the LUX threads....keep up the great work.
Wow this is very cool I'm currently in the process of doing the same thing. It's been interesting reading this thread, I have a few questions though, if you don't mind. How many extra clutches and steels were you able to add ? I have only gone as far as adding one clutch and one steel by removing 1 mm from three surfaces. Do you have some miles on it now and is it still working well ? I have got the cooler and filter system worked out for my case but as of yet have not assembled or tested so changes may be required but it came together fairly easily. I'm interested if you have checked your operating temperatures as well?
Very cool. I'd love something like this, even with 1000+ lbs in the bed I blow my tires off trying to get rolling quickly.
Only cut enough to add 1 more clutch and 1 steel, anymore and the last clutch will ride up on the hub and the encoder will crush it like mine.
As of now a little over 4k miles on mine, it did eat another encoder motor in the rain again. I believe it was the aftermarket encoder set-ups(the encoder would occasionally chatter with the aftermarket ones; they're inferior build quality and take short-cuts on bearings and the motor gear that I believe will cause durability concerns and binding), once I switched to a OEM one, I haven't had another issue since.
I still use it about daily when I want to have some fun lol. Other than that, no progress on the rest of the plans - Busy with life, saving up for a 17 and new lady friend so... We all know how that goes :roflmao:
As of now a little over 4k miles on mine, it did eat another encoder motor in the rain again. I believe it was the aftermarket encoder set-ups(the encoder would occasionally chatter with the aftermarket ones; they're inferior build quality and take short-cuts on bearings and the motor gear that I believe will cause durability concerns and binding), once I switched to a OEM one, I haven't had another issue since.
I still use it about daily when I want to have some fun lol. Other than that, no progress on the rest of the plans - Busy with life, saving up for a 17 and new lady friend so... We all know how that goes :roflmao:
I was reading this and was curious about the programing side. I work on BMWs and from what I understand the awd cars are programed to have the clutchs applied under something like 30 mph and steering angle less than a certain amount (unlocks for turning). So the car is always in 4wd on acceleration. After that I would guess it applies based on throttle amount and front/rear slip.
Do GM awd's need to see slip to apply? can you set it to apply under a certain mph?
Also BMWs computers are calibrated to the clutch pack thickness and motors have a classification resistor to tell the computer the motors resistance for dialed in application. Do GM's have any calibration?
I think alot of ppl forget the front and rear should be moving at the same speed when rolling so if the motor reacts fast enough to minimum wheel slip the clutches and steels aren't really slipping. They just need to be strong enough to not slip.
Very cool build. Way beyond what I would be able to figure out on my own. :thumb:
Do GM awd's need to see slip to apply? can you set it to apply under a certain mph?
Also BMWs computers are calibrated to the clutch pack thickness and motors have a classification resistor to tell the computer the motors resistance for dialed in application. Do GM's have any calibration?
I think alot of ppl forget the front and rear should be moving at the same speed when rolling so if the motor reacts fast enough to minimum wheel slip the clutches and steels aren't really slipping. They just need to be strong enough to not slip.
Very cool build. Way beyond what I would be able to figure out on my own. :thumb:
It depends on the model year, prior to 02 I couldn't tell you much - I could speculate. 03-07 varies the clutch rate on slip (15 rpm), throttle, speed (25mph+ the clutches engages more to bias more power forward) and ABS activation.
The system relies on a baseline of what the clutch pack is set at, from there it will adapt based on clutch wear, assuming the encoder sensor is good.
It is rather a picky system, as an improper TCCM calibration will cause encoder failure - the apply fork rides on the pressure plate a bit in 2wd and there is enough play to constantly rotate the encoder motor, which causes wear on the sensor brushes (this is why they fail).
There is a calibration out that applies constant pressure on the clutches to prevent this.
07.5+ are WAY more robust in terms of sensors, as the design of the pressure plate prevents the above mentioned issues and the programming actually has more thought into it. The #1 complaint GM had with autotrac back in the day was crows-hop, so they created autotrac fluid to mask the issue.
So with the new ones, they integrated the TCCM into the EBCM and fed it 4 channel ABS signals so it measures the wheels vs the propshafts. Then they gave it steering wheel position signals too, this prevents the crows-hop and allows a bit more tire size difference front to rear. It also has it's own encoder sensor outside of the motor and IIRC the motor has one for reference and diagnostics as well. They also have a specific programming feature to learn the clutches too. 100x smarter system.
The system relies on a baseline of what the clutch pack is set at, from there it will adapt based on clutch wear, assuming the encoder sensor is good.
It is rather a picky system, as an improper TCCM calibration will cause encoder failure - the apply fork rides on the pressure plate a bit in 2wd and there is enough play to constantly rotate the encoder motor, which causes wear on the sensor brushes (this is why they fail).
There is a calibration out that applies constant pressure on the clutches to prevent this.
07.5+ are WAY more robust in terms of sensors, as the design of the pressure plate prevents the above mentioned issues and the programming actually has more thought into it. The #1 complaint GM had with autotrac back in the day was crows-hop, so they created autotrac fluid to mask the issue.
So with the new ones, they integrated the TCCM into the EBCM and fed it 4 channel ABS signals so it measures the wheels vs the propshafts. Then they gave it steering wheel position signals too, this prevents the crows-hop and allows a bit more tire size difference front to rear. It also has it's own encoder sensor outside of the motor and IIRC the motor has one for reference and diagnostics as well. They also have a specific programming feature to learn the clutches too. 100x smarter system.
This thread is truly awesome!!!!!! I'm amazed at the depth of it. Great job! Thanks for posting it
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