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Discussion Starter · #1 ·
Okay so,
Weird thing happened to me twice now. My car (3.6l/5L40) while cruising down the highway at 110 (kmph) shifts into park for a couple seconds then the car resumes.
The physical shifter itself is in drive. I hadn’t touched it. Just the digital display reads out P (for park) and it kicks the cruise off. Then it downshifts trying to figure itself out then a split second later it’s back to normal (in D again on the display) minus the cruise function until the car has been restarted.

Has anyone else run into this issue? I’m assuming it’s either a trans selector switch or a bad ground. But if it’s a common issue and someone knows it may save me some time and money!

Thanks in advance!
 

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To be clear, the dash indicator says its in park but it does not actually shift to park?

I think you're on the right track with the gear indicator switch (what ever serves that purpose on the 5L40)
 

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Discussion Starter · #3 ·
To be clear, the dash indicator says its in park but it does not actually shift to park?
Exactly. It tries to downshift though usually resulting in a miss and coast until it comes back

QUOTE="383_Stroker, post: 3725930, member: 23377"]
I think you're on the right track with the gear indicator switch (what ever serves that purpose on the 5L40)
That’s what I’m assuming it is. I don’t have time to look at it now though so it’ll be a winter project.
I wanted to swap to a 6L50 anyway so if this 5l40 explodes in the meantime it’ll be a good excuse lol
 

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Well considering that these cars are 14-15 years old lots of annoying little gremlins are going to pop up.

Time to break out the volt meter or visit a shop that specializes in auto electric.

I had a great guy here in Niagara Falls but he recently retired.
 

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Check to see if P0850 is stored in trans data, If so the trans shaft switch inside of trans at shift shaft will need replacing
 
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You can also check the orange/black wire coming from trans sw at trans to ecm for short to ground at its haress/s, when that wire is grounded it tells ecm it is in park
 
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