Auto trans won’t go above 6th gear

[Sticks702]

So I am having a new issue with my 22 Sport Max tow. It has been re-geared to 5.13 with e-lockers, the housings are trussed, front gusseted, with Reid knuckles and Timken main unit bearing housings. Computer flashed with Superchips FlashCal for gears and tore size. This was all done a little over a year ago. I had been running 37’s and just upped to 40’s, with the tire size upgraded with the FlashCal again. Here is the issue. The engine revs abnormally high between shifts and it wont’t go a above 6th on the highway l, running @ 3200 RPM. If I shift it manually, it accelerates normally and will easily run 7th or 8th on the highway @ 2100rpm. Running on flat ground @ 70mph, in 8th gear, if I move it back to auto, it shifts down to 6th. It almost seems like the trans doesn’t know what speed the vehicle is going. The trans shifts fine when it does shift, and shifts smoothly in manual mode. There are no shudders/clunks or anything else that would make me think something internally is failing. I tried to reflash with the FlashCal again tonight and got an error that it could not authenticate the ABS system. Based on that, I am thinking in my wheeling adventures I may have a wheel sensor that has failed/is failing. No lights on the dash. Opinions please?

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[Clark]

Piss poor engine engineering, engine performance, a product of the computing world,

 

[sharpsicle]

Piss poor engine engineering, engine performance, a product of the computing world,

What? Did you even read the post?

Sounds to me like it needs to re-learn the shift points.

 

[Clark]

Yes i did

 

[Greg_L]

Piss poor engine engineering, engine performance, a product of the computing world,

You know these same types of issues can happen in vintage analog vehicles with gears and tire changes, right?

 

[Clark]

Carburetors use to fail also, trannys did to, but the engineering in the 3.6 sucks, thats all i was saying, sorry if i offended anyone.

 

[Greg_L]

Carburetors use to fail also, trannys did to, but the engineering in the 3.6 sucks, thats all i was saying, sorry if i offended anyone.

I don't think anyone got offended. It's just your yelling at clouds is not really helpful or even necessary in this case. His truck would run and shift fine as designed. He altered it so it needs to be figured out. No big deal. Surely you understand that.

 

[ScottBeach]

If the truck shifts normally in manual mode. I would suggest refresh the pcm of the transmission.

 

[Mr.Wilson]

I’m wondering if someone hosed you on a regear job? I’m wondering if they actually swapped out gears. Only reason I’m saying this is because I’m running 37’s on 2022 Sport S with max tow (4.10 gears) and my truck does exactly what yours is doing. Revs very high between shifts. Hangs forever between 4th and 5th. Then when it gets to 6th it stays there for the duration. I don’t see 7th or 8th unless I’m going straight down hill or I have a 50mph tailwind. Everyone saying he altered his vehicle and that’s why his transmission won’t shift. I miss the days when we took stock trucks (and jeeps). Slapped 40” mudders on them and pounded them through the swamps and still drove them home and they shifted just fine. I’ve put 35’s-37’s on every single truck I’ve ever owned without one issue and the ONLY vehicle that has been a constant headache has been the JT.

 

[DrewsJT]

Piss poor engine engineering, engine performance, a product of the computing world,

Search the internet, the of 850 is a very good trans

 

[Greg_L]

All of these systems are related. Digital or analog, computer or vacuum/mechanical linkage, it does not matter. These things are designed to work within a certain range of parameters and have to work in harmony. Changing one variable can have a ripple effect down the line.

In racing it's very common to change the diff gear ratio. No big deal. But then you have to take tire diameter into consideration. Not necessarily for shifting, but for keeping the engine in it's powerband. That also affects transmission gear ratios. That can also affect torque converter stall speed in an auto trans, and going further, cam lobe separation and duration. Going even further, the intake manifold plenum design. All this for a gear swap. It's all related.

 

[Minty JL]

What? Did you even read the post?

Sounds to me like it needs to re-learn the shift points.

I agree with a trans relearn procedure. Do you have a friend that has an Autel or some other advanced bi-ditectional tool?

Do you have a TAZR? Might want to consider getting one, plus the other functionality is nice to have. Also, what is the build date on your '22?

 

[Clark]

I agree,

 

[Sticks702]

I agree with a trans relearn procedure. Do you have a friend that has an Autel or some other advanced bi-ditectional tool?

Do you have a TAZR? Might want to consider getting one, plus the other functionality is nice to have. Also, what is the build date on your '22?

Build date is 6/21/22. I am waiting on a BT ODB reader to use with J-Scan vs taser, but I need to get the stupid Superchips tuner to reset it to stock before I start messing with it.

 

[Sticks702]

I’m wondering if someone hosed you on a regear job? I’m wondering if they actually swapped out gears. Only reason I’m saying this is because I’m running 37’s on 2022 Sport S with max tow (4.10 gears) and my truck does exactly what yours is doing. Revs very high between shifts. Hangs forever between 4th and 5th. Then when it gets to 6th it stays there for the duration. I don’t see 7th or 8th unless I’m going straight down hill or I have a 50mph tailwind. Everyone saying he altered his vehicle and that’s why his transmission won’t shift. I miss the days when we took stock trucks (and jeeps). Slapped 40” mudders on them and pounded them through the swamps and still drove them home and they shifted just fine. I’ve put 35’s-37’s on every single truck I’ve ever owned without one issue and the ONLY vehicle that has been a constant headache has been the JT.

I thought that but the Jeep performs just fine in 7th & 8th if put there manually. I can roll 70
going uphill in 7th at @ 2000 RPM. I think the ones mentioning shift points are on to something. I just need someone to help
me flash it. Thought that is what the Superchips was supposed to do when flashed to the 5.13 gears. I am pretty sure the updated tire size that I entered is purely for the speedo.

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