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The casting is pretty rough, but they did a good job on the holes and threading. Though, the holes were so tight tolerance I had to open all of them up a drill size or 2.FIFY
Did yours come with a gajillion casting flaws and apprentice marks on the threads like my 4LShixtty adapter did?
CTSV or ZR1 TC?
Yes, both use the same T43
Guys, until 2011, the OS, drivers and programming are year to year specific.
Agreed, I’m using an E67 that’s programmed as a 2010 H3T alpha and a T43 TCM that was programmed to an 07 Denali and I just swapped it to an 08 Chevy Silverado 6.0. The OS was the same on the 07 and 08, but it still allowed me to segment swap it in HPT and nothing got bricked.
Went wheeling locally again last weekend, had a good time. We were on the trail by 7 and off by 11ish before it became 100* outside.
This is tech and probably boring to most but I hope it solves someone else’s issues in the future.
Some exciting news is I finally have an accurate speedo in 4 low! I get anal about this stuff. I know it’s stupid but I really do get ocd about it.
So the reason it took so long is that my tuner needed me to send him my tcm which is inside the trans and I didn’t want to do that. I do miss the tcm being external like it was on the 4l60. Anyways, he has a loaner software tool but the cable was not working. He was having issues finding a replacement cable for his tuning software. I guess it’s discontinued and parts are hard to come by but he’s sticking with that software because it’s much less restrictive than HPTuners. He can do some really cool custom shit with his that HPTuners just doesn’t do. Anyways, it’s just a speedo issue in low range and wasn’t affecting the performance so I said find a cable and send it my way when you can, no rush. He’s had no luck with his cable and I finally dug further into it with my HPTuners setup.
Sure enough I could swap the TCM tunes from another vin IF the operating systems are the same operating systems. There are variances in an OS like 2wd vs 4wd.
There are definitely concerns, some say they will brick a TCM, some say they won’t. The 6l80 is a picky SOB and I know it has bricked some TCMs according to the internet. So I was taking a gamble all for a stupid speedo issue in 4low.
But I found a file from a 08 Silverado 4x4 with a 6l90 that has the same OS as my 07 TCM from a Denali with AWD. Since it had AWD it didn’t have a low range provision. I made the tune identical, hoped it wouldn’t brick and it didn’t!
Everything is identical except for 2 things.
1) the speedo reading. Going back to my 4l60 days the speedo got its info off the VSS at the back of the t case. This was great. Whether in 4low, 2hi, double low, etc. it always read the same speed because the output shaft was spinning based on road speed, not gear ratio. The problem I had was if it didn’t know I was in 4lo it would go into limp mode so I had a switch that would ground out and grounding out that pin would tell the pcm I’m in 4 low. So if I didn’t use that switch I would go into limp mode. Dumb but it worked.
Fast forward to the 6l80 it doesn’t care if the computer knows it’s in low or high, it won’t go into limp mode which is awesome but it doesn’t use a t case VSS it uses a speed sensor off the tail of the trans, which does care what range it’s in from a speedo standpoint. So before if I’m in 1.96:1 it would read the speedo 1.96 times faster then I was going. Since I used 1.96 to bomb around on dirt roads at 50 mph, it would say I’m doing 100 mph. In 2.72:1 it was saying I was going 2.72 times faster than I was. So at 30 mph it said 81 mph. What really drove me nuts was 5.33:1 in double low at just 12 mph it said I was doing 60 plus. Even doing 5 mph it was 25+ mph. It drove me bonkers. There was no point in flipping my 4 low switch because it didn’t care.
So now that this vin has 4wd attached to it. It’s a silverado so 2.72:1. I flipped switch and the speedo is dead nuts accurate. What does suck is since it’s still reading at the front of the t case at 20 mph in 1.96:1 the speedo says 15 mph. It’s a little off but not horrible.
5.33 is still about 50% off so at 12 mph it will say I’m doing 23 mph but wayyy closer then before. I do spend a lot of time in 2.72 so I’m happy there.
2nd change is before my PRND321 I had PRND then 3 was tap shift, 2 and 1 were not used.
Now it’s PRND 3 is not used 2 is tap shift and 1 actually holds first which is cool.
I also found out that I can transfer a bin file to HPT file on HPtuners. I think it’s 50 bucks to do so but I’ll gladly pay that vs pulling my damn tcm or paying money to ship crap. So I will talk to my tuner and see if he can write a file on his end and I’ll convert it.
Since he can do custom stuff I can’t on HPT I’d like PRND321 to all be utilized. I’d like 3 to be tap shift, 2 to be 2nd, 1 to be 1st.
I’d also like to see if he can just have me rewire in my old VSS on the back of my 205 I’ll pin that to the pcm and use that. I will look to see if there are early 6l80 applications that had a t case VSS with the same OS because I’d like that, then I can ditch the 4 low switch all together and it will always read right.
Anyways, this is the fun stuff I geek out over.
www.transmissiondigest.com
Dude, you said you tuned it, using HP Tuners, that you found files that had the same OS and the features you wanted. You also changed up your harness, which guess what? That's what the PCM's do from year to year, change input/output pins. That's why they suggest matching the year of the PCM to the year of the TEHCM. The OS's also vary CANBUS messages from year to year, based on the PCM and Body Control Module changes.
That is a great point. I think it is valid for some for sure. In my case I have HPtuners and if I am going on a week long UA type trip I’ll probably bring a laptop with me.
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Neat!
why would you need that when you can program your ECU to do the exact same thing and not need an extra box ?
