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JK SUPER DUTY SWAP GEAR RATIO ERROR FAULTS

Boombox

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Jul 2, 2012
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143
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Franklin TN
I just recently finished a super duty axle swap in my 2012 jk and have been fighting gear ratio error faults in the trans. p0731 fault keeps returning...I'm running the artec 60 tooth tone wheels in the rear and the 60 tooth in the front with 5.13 gears. I'v tried reprogramming ratio with an AEV procal and obd j scan. I've programmed ratio to 4.44 gears and have tried every ratio down to 3.21 and up to 5.38s with no luck. Even tried reflashing the tcm and doing several hard resets. Anyone have any ideas?
 

Lil ugly

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Oct 6, 2011
Messages
617
Location
Jacksonville, Fl
Just as a devil's advocate, have you taken a moment to verify that you have good sensors at all four corners, no wiring issue giving you an intermittent signal etc. I have chased problems with high level solutions on a multitude of occasions just to find out that i should have verified the basics first.
 

Boombox

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Jul 2, 2012
Messages
143
Location
Franklin TN
Yes. No signal dropping out or anything like that and they are all reading same wheel speed. I can go in with wiTech2 and monitor all 4 speed sensors.
 

Lil ugly

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Oct 6, 2011
Messages
617
Location
Jacksonville, Fl
When I look up the code for jeep it gives the definition as you defined it ( gear ratio fault). However further research shows that the code is generated by a discrepancy in transmission input shaft speed vs transmission output speed. I dont believe the issue would be in the vehicle reading the tone rings so much as it is having an issue with the amount of speed difference in the input and output of the transmission. Is the vehicle shifting into first as its supposed to? Have you double check tranny fluid levels? If your reader has the capability I would look at your transmission values and see if everything seems to be within spec there.
 

Boombox

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Jul 2, 2012
Messages
143
Location
Franklin TN
Yea the nag transmission gets its output speed from the wheel speed sensors. It is going directly into 4th shortly after taking off. Trans fluid and level are good. Issue didnt start until right after the axle swap. I had originally programmed it to the 4.56 in the stock axles and had no problems. It is a software issue i believe but im not sure what to do to correct this.. Hp tuner? Iv done tons of gear swaps for customers used AEV procal or superchip to program new ratios and have never had a problem like this. Go figure I have a headache with my own jeep...
 
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Lil ugly

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Oct 6, 2011
Messages
617
Location
Jacksonville, Fl
seems odd to get the output transmission speed from the wheel speed sensors since it would be complicated by the transfercase gear as well as the differential gear. Makes sense for abs and traction control, just seems like a long run around for tranny output speed. I run a manual valve body so I did spend much time looking at what my HP tuners can do for the tranny so I would have to look at what is available in it.
 

Lil ugly

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Joined
Oct 6, 2011
Messages
617
Location
Jacksonville, Fl
Do you have to send your computer in to be unlocked by them? I know the Ram computers have to unlocked first and it can only be done by sending it in to them supposedly. Some of the late model GM's are the same way. Not sure on Ford.
 

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