dstevens
Well-Known Member
- Thread starter
- #1
Has anyone else noticed that their transmission upshifts early in 4LO under load? I noticed when climbing a steep rocky hill in 4LO when the Jeep needs more throttle the transmission will short shift and then it really struggles to go anywhere. Worse still at elevation.
I've read out the TCM and sure enough the 4LO shift pattern is regressive in the lower three gears for some reason. What I am trying to do is find out if this is a 2.0T thing, or just a 2024 thing.
The way to find out is to engage 4LO, check the transmission starts in first gear (it will either be 1st or 2nd depending on the slope. A slight slope will encourage it to use 2nd gear.). Then apply foot brake and throttle at the same time without allowing the Jeep to move and see if the transmission shifts into 2nd gear as you get past 3/4 throttle.
Here's (one) of the shift pattern tables. If you're not familiar with them the Y axis is throttle and the table value is output shaft speed (= vehicle speed).
Translated to actual vehicle speed it looks like this
For example, if you are not moving once you get past 44.9% throttle it will shift to 2nd gear. If you are going up a steep hill at 5 mph (about 900 output shaft rpm) it will be in 2nd gear. If you give it more throttle then at 80% throttle it will shift into 3rd gear. Protecting the drivetrain you say? Odd way to do that. Normally the TCM tells the PCM to reduce torque.
I've read out the TCM and sure enough the 4LO shift pattern is regressive in the lower three gears for some reason. What I am trying to do is find out if this is a 2.0T thing, or just a 2024 thing.
The way to find out is to engage 4LO, check the transmission starts in first gear (it will either be 1st or 2nd depending on the slope. A slight slope will encourage it to use 2nd gear.). Then apply foot brake and throttle at the same time without allowing the Jeep to move and see if the transmission shifts into 2nd gear as you get past 3/4 throttle.
Here's (one) of the shift pattern tables. If you're not familiar with them the Y axis is throttle and the table value is output shaft speed (= vehicle speed).
Translated to actual vehicle speed it looks like this
For example, if you are not moving once you get past 44.9% throttle it will shift to 2nd gear. If you are going up a steep hill at 5 mph (about 900 output shaft rpm) it will be in 2nd gear. If you give it more throttle then at 80% throttle it will shift into 3rd gear. Protecting the drivetrain you say? Odd way to do that. Normally the TCM tells the PCM to reduce torque.
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