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am I wrong or are other people stupid?

skipnrocks

Well-Known Member
Joined
Oct 1, 2011
Messages
1,355
Location
Billings Montana
I am super annoyed with ez tcu. here is why they keep passing the buck but dont or wont help trouble shoot. Here is my issue the computer senses rpm and output speed and shifts accordingly. In high range it does it flawless on my 4l80e. It gets speed from the transmission output. So hypothetically at 2krpm at the motor and 1k rpm at the transmission it shifts from first to second and the buggy is driving 25mph. When I shift into low range because it doesn't actually know that the vehicle is moving slower with the same parameters it should shift from 1st to second at 2k and 1k inputs even thought the buggy is now going 10 mph.

Here is the issue, in high it works flawless, in low it shifts to second under low rpm load but as soon as I accelerate it not only fails to up-shift but actually down shifts and stays there. Ez tcu says that its because the speed is pretcase but I say it should up-shift faster in relation to actual vehicle speed and there is no reason it should be down shifting. I talked to advanced adapters and they said basically what i am saying and that it shouldn't matter that it doesn't know the tcase is downshifted.


So what do I do. Bag it for a better system? I cant even begin to troubleshoot because they wont give me any direction. Other than get a gm speed sensor for the t-case. Bad news is unless i replace my output on my atlas to a vss unit I cant do that.
 
Unless the EZ Tcu has a input that will allow you to tell it when you're in low range don't waste your money putting a GM sensor in your transfer case, it will not shift correctly when in low range.

Have you tried starting from scratch going through the setup process in the TCU? there are two speed sensors on a 4L80, make sure youre plugged in the rear speed sensor.

My guess would be something in the programming of the TCU. It doesnt have any way to know how fast you are actually going so it should shift the same in low range as it does in high range. The only difference would be the throttle position sensor because you wouldnt be applying as much throttle to accelerate in low range as you are in high range. Have you checked the throttle position sensor? Maybe a bad spot in the sensor?
 
I had a friend call me tonight and he said that a lot of the four-wheel-drive 4l80e transmissions didn't have a speed ring in the rear sensor port. And that's why there is typically a plug back there. This seems like it might be a possibility. I wonder if the VSS sensor in the front of my atlas will give a proper signal?
 
SBJeepn said:
I had a friend call me tonight and he said that a lot of the four-wheel-drive 4l80e transmissions didn't have a speed ring in the rear sensor port. And that's why there is typically a plug back there. This seems like it might be a possibility. I wonder if the VSS sensor in the front of my atlas will give a proper signal?

I had a similar problem, because I am running a 263/205 doubler. My 4l80e did not have the ring in the rear of the transmission. It was out of a 2001 3/4 ton 4x4. I used all of the stock computer and harness. My solution was to take the speed sensor and ring out of the stock 263 transfer case, (the planetary was being used for the doubler any way) and adapt them to the tail shaft / housing of the 205. It only required having the ring machined down a little, and a flat spot milled across the tail house. The housing was then drilled and tapped for the sensor. I didn't even have to extend the wiring harness.

To make it shift right ( for the most part) I had Wayne Hartwig reprogram the computer. The stock LO / HI input from the t-case is wired to a momentary push button. This takes care of being in single LOW. For double low, I just had him change the Tow / Haul shift table up. Basically I asked him to try to make it hold every gear as long as possible. The Tow / Haul input is wired to an OFF / On toggle switch.

It shifts normal in HIGH, and with the doubler section only in LOW. (As long as I remember to hit the LOW switch). With the doubler in high, and 205 in LOW, it still shifts almost correct, but with raised shift points due to the difference in case ratios. In Double low, it basically will never up shift unless you put it in D and rev it to the moon. (As long as I remember to hit the TOW/Haul switch) The only issue I have had is that if in D / LOW / LOW going down hill, with throttle position at 0, it will upshift to 2nd instead of engine brake. I just pull it down in to 1 position when down hilling or hold the throttle slightly off idle. Then it will hold and provide plenty of engine brake.

I know this doesn't directly answer your question, but maybe it will help give you some ideas.
 
(posted before hucklebuggy) That's just because they were running an automatic tcase. It has 3 speed sensors if I remember. So at that point they were using an input speed sensor that translates to the same speed as Trans output speed.

Earlier 4l80s with a manual tcase ran both sensors on the Trans.

If your model had a plug instead of a sensor on the Trans, he's correct. If it had a sensor the chances are good there is a reluctor ring inside.

Hucklebuggy drives in LOW LOW LOW LOW all the time. Even on access trails so that's the only reason he would need to program the TCM not to upshift
 
That's a good answer. I have a speed vss sensor in the adapter of my tcase. I am going to give that a shot. But turns out advanced adapters has a sensor that bolts onto the output of the tcase and has a ring that bolts onto the rear yoke. I also have a 8k pulse sensor built into the rear of my atlas. I guess Dakota digital sells a little box that will cut the signal in half to 4K which is what I need. Hopefully my built in vss in the front of the atlas works then I can be done.


I'm still super annoyed that tech was no help. They even acted annoyed that I was asking for help. And not one of them even suggested that the four wheel drive trans didn't even have the rear ring for a proper sensor.

Mine did have the plug. To start. This was a new area outside my experience. I just pulled the plug and threw in the sensor. Lol.
 
Reminds of the Fox tech line. Guys who "supposedly" have setup and tuned race rigs couldn't tell me a single oil or nitrogen level spec to start with. Never even asked me about my rig.

I feel your pain
 
LightBnDr said:
Reminds of the Fox tech line. Guys who "supposedly" have setup and tuned race rigs couldn't tell me a single oil or nitrogen level spec to start with. Never even asked me about my rig.

I feel your pain


Exac freakin tly. If your the expert be the expert. If not get a job at mcdonalds
 
I did a 6.0 4L80 swap in my 06 jeep I made the mistake of buying a 4WD 4L80 and realized the issue I would have luckily before it was in the jeep The 4WD version does not have the reluctor ring on the shaft for the output speed sensor although it does have the hole with rubber plug for the sensor I used a 2WD main shaft in mine a it shifts great it has a rubicon 241OR case behind it
 
So it turns out ez tech support is extra ducky. They kept telling me I needed a 4K ppm signal and it never would work. So I talked to Dakota digital and they said probably needs a 128k. So I asked ez if that was accurate they acted annoyed and said no. So I got a 4K generator and guess what. Didn't work. So I called Dakota to troubleshoot and they said they 128. Once I set it for 128 boom it's working great.
 
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