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Need some Autoshift Information


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Closing in on a transmission issue on our truck where the autoshift won't stay in reverse. Rickeieio Pope  said he thought he remembered someone else having this problem but didn't remember how it got resolved.  For more detail on what's going on, read the other thread. In esseesse, tranny lost all it's oil, got hot, & burned up. New clutch,transmission, etc. Down to thinking it's the shift tower or the XY box.  If you remember the "Pops out of reverse" issue or who posted it or how they fixed it, PLEASE post it or send me a PM.  More big money down the river in the early afternoon.

Thanks in advance

Paul & Paula


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Hmmmm, Isn't "jmb" the same as "bags"?  Same issue, same dealer, six years later?

Anyhoo, Paul, it looks like you might be in for a cheap fix.  I'm gonna guess that's a pretty common switch.  I think there are several hanging on the sides of my tractor trannies.

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You folks are amazing - thanks for the quick response. Stopped by the shop this morning and they had gotten to roughly the same conclusion that all the above had reached.  Mechanical issue in the transmission proper, such as an issue in the shift tower. Both are being checked as I write this. Looking for high friction/roughness in the shift fingers etc. Alternatively, looking for electrical issues and operation at the XY box. Going (if needed) to purchase a new box, try it, and if it doesn't work, return it.  Eliminates a LOT of troubleshooting hours.

Stay tuned



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  • 2 weeks later...

Here's the promised update. Turns out several folks were headed down the right path.  Reverse sensor, but not quite what you think. And contrary to several of the closely held opinions, the sensor proper was not the culprit.

First, remember that the transmission emptied itself of oil due to a cracked line going to/from the oil cooler. That resulted in several pieces seizing together, most notably the bell housing to the motor.

Second, there were some issues with the EZ pedal  clutch and the hydraulic linkage. It works, but with greatly reduced pedal throw.

With all of the hardware back in place, the transmission would still not stay in reverse. If you will recall, the mob consensus was that the reverse sensor had failed. It was checked on 3 separate occasions. Passed every time. Failed sensor did not show up on Failure Tree analysis. Replacement sensor test did not correct the problem.

On the last test, the tech was checking connections, and decided to check the actual wire. It failed, wasn't clear if it was burned due to overheat issue or crushed due to seized up issue. Replaced wire, problem solved. 

I have to give these folks credit. This was a tough repair. Even without me bird-dogging them it would have been tough. They kept at it, solved the problems, didn't kill me with labor charges even though some of the diagnostic labor hours were well past their estimated hours.

Precision Diesel Repair in Shepherdsville, KY - check 'em out


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