Novak Conversions Jeep Wrangler JK radiators

Code P0733

ObiWan

ObiWan

Jedi Master
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Oct 12, 2023
Messages
10
Location
Clayton, North Carolina
Alright, yet again the winter arrives and my early Christmas present is here. I’m getting a P0733 code (gear 3 ratio incorrect). I reset it, drove down the street and it shifted fine up to 3rd gear and then wouldn’t shift up or down out of 3rd until I park it. I have gotten a 4.55 gear ratio for the axles running with 35 inch tires. I got one of those flashcal things from the shop who did the work so I could set everything up for the computer. Everything has been running good, I got all the work done a little over a year ago and no big issues like this until now.
 
Automatic trans I assume? Have you serviced the fluid and filter at all?

The 42RLE has both input and output shaft speed sensors. I'm not sure about the NAG1 transmissions, but I suspect they do as well. One possibility is that when the cold weather kicks in, it's contracting the tone ring slightly, or the sensor within the body, just enough to show a speed discrepancy. I have seen similar issues with other transmission, the ZF on a recent Hemi swap, but the guy had a bad shift solenoid that was causing a slow shift, allowing RPMs to jump a bit (this wasn't cold weather related).
 
pc1p said:
Automatic trans I assume? Have you serviced the fluid and filter at all?

The 42RLE has both input and output shaft speed sensors. I'm not sure about the NAG1 transmissions, but I suspect they do as well. One possibility is that when the cold weather kicks in, it's contracting the tone ring slightly, or the sensor within the body, just enough to show a speed discrepancy. I have seen similar issues with other transmission, the ZF on a recent Hemi swap, but the guy had a bad shift solenoid that was causing a slow shift, allowing RPMs to jump a bit (this wasn't cold weather related).
Click to expand...

Yes it is an automatic and I had the fluid serviced last year done right around 95-100k miles. The filter I have yet to service which saying it now I probably should definitely check. The fluid is full and still has a nice pink color to it. The speed looks normal but it just won’t shift out of 3rd gear once it gets to it.
 
pc1p said:
I think this is what they do in "limp mode". I had a similar issue, and my Jeep would also throw ABS codes and light up the Christmas tree, when I had bad battery cable terminals.
Click to expand...

I also have the abs light on and have a new negative battery terminal but have yet to install it. Could this be the issue it’s having?
 
ObiWan said:
Yes it is an automatic and I had the fluid serviced last year done right around 95-100k miles. The filter I have yet to service which saying it now I probably should definitely check. The fluid is full and still has a nice pink color to it. The speed looks normal but it just won’t shift out of 3rd gear once it gets to it.
Click to expand...

Are you able to "manually" shift it out of 3rd?
 
Found this:

Yes, cold weather can significantly affect Jeep Wrangler shift solenoids, primarily by thickening the transmission fluid, making it sluggish, which exacerbates existing solenoid issues or causes delayed, hard, or erratic shifting (especially 1st to 2nd or 2nd to 3rd) until the fluid warms up and flows better. Cold temperatures make solenoids less responsive, hindering their ability to regulate fluid pressure for smooth gear changes, often leading to slipping or hesitation until warmed.

How Cold Affects Solenoids & Shifting:
  • Thickened Fluid: Cold makes transmission fluid viscous, slowing its flow and reducing hydraulic pressure, which solenoids rely on.
  • Sluggish Solenoids: Stiff fluid makes solenoids work harder and slower to open and close, causing delays.
 
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