Loud clunk and rough shifting into reverse when cold

[GCATX]

Unrelated to shifting into reverse while rpms are elevated but trans shifting related: There is a PCM update that has a very significant positive effect on the trans shift performance. I had a very abrupt 1-2 shift while in sport mode. So abrupt that I think it was only a matter of time before something broke. I updated the PCM and now it shifts very smoothly even in sport mode. You need to either visit a dealer or visit someone with IDS.

I need this done. Is there a TSB or just ask dealer if there are any updates? Mine sometimes chirps the tires simply pulling away from a stoplight at granny throttle. 4-5 shifts rough too.

 

[lifeline]

I need this done. Is there a TSB or just ask dealer if there are any updates? Mine sometimes chirps the tires simply pulling away from a stoplight at granny throttle. 4-5 shifts rough too.

No TSB. Just go to the dealer and tell them about your trans issue. Tell them you know there is a PCM update that may resolve the issue and ask them to update your PCM. It should take them 10 minutes to do. The update takes only a couple minutes from start to finish.


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[rtmozingo]

It seems my 2017 has been doing this of late. Flat or incline, cold or hot, once per shift into reverse, usually when I toe in on throttle. Hoping it is spring clunk and not drivetrain related...

 

[1badjk]

I did the TSB when mine was shifting rough and it helped for a while and then the rough shifting started again. So I took the truck in and this time they replaced the valve body in the tranny. Good so far but only had it back for a few days.

 

[rtmozingo]

I did the TSB when mine was shifting rough and it helped for a while and then the rough shifting started again. So I took the truck in and this time they replaced the valve body in the tranny. Good so far but only had it back for a few days.

Wife says noise is coming from back left tire area, so thinking it is the suspension in my case.