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Erratic shifting

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47re shifts in and out of all gears does not do it first thing in the morning when when everything gets all warmed up it will jump in between gears and 1-2 will be super late. Fresh rebuild with only 2000 miles on it. Replaced gov pressure sensor and transducer. Sometimes it will go away for a while if I do an apps reset but not always. Any help would be greatly appreciated thanks!

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  • Owner

First off welcome to the family.

 

Then the next thing I'm going to suggest is to do the W-T ground wire mod. 

This should fix the erratic shift and whatnot. Make sure to remove any noise filters and any weird ground wires added they will not be needed. 

 

The only other thing to look at possibly replacing is the output speed sensor typically in the tail shaft of the transmission. 

  • Author

Says I don’t have permission to view the content, but I’ll give that a go tonight hopefully! Thank you I’ll update when I try it

 

  • Author

Did the W-T ground mod still no dice I’ll try the output speed sensor tomarrow and see if it helps

  • Owner

The output speed sensor could be it then being the speed sensor could cause the transmission to downshift randomly way lower than it should because it thinks the speed is much lower. 

  • Author

Update 300 miles after installing new output speed sensor no issues so far. Seems to have cured the issue. Weird how no codes set or anything

  • Author

Sad part is, I rebuild them for a living and had never seen this issue before

  • Owner

The magnet in the sensor degrades as the magnet is heated and cooled then the signal pulses get weaker. The coil is still good so the PCM will not throw a code because of connection. 

 

Kind of the same with crank sensors in the early 2nd gen 24Vs.

The PCM could check if the transmission sensor and the speed sensor in the rear axle are both pulsing and flag it if not. Obviously the PCM doesn't do that. When my sensor failed a few years ago I was stuck with only first gear. By removing the transmission relay in the PDC it goes into limp mode which just defaults to 3rd gear. Much better to drive home in 3rd instead of 1 st. When I was a kid I was playing around in snow and my rear wheels went from 100 mph to zero instantly on dry pavement. That shredded the nylon gear on the governor in the old GM th350 so I was stuck in 1st.

  • Owner

Sadly the pulse isn't checked really only if there is connection. So if you unplugged the sensor and key on it should throw a code.

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Welcome To Mopar1973Man.Com LLC

We are privately owned, with access to a professional Diesel Mechanic, who can provide additional support for Dodge Ram Cummins Diesel vehicles. Many detailed information is FREE and available to read. However, in order to interact directly with our Diesel Mechanic, Michael, by phone, via zoom, or as the web-based option, Subscription Plans are offered that will enable these and other features.  Go to the Subscription Page and Select a desired plan. At any time you wish to cancel the Subscription, click Subscription Page, select the 'Cancel' button, and it will be canceled. For your convenience, all subscriptions are on auto-renewal.