Selecting reverse or drive from park position

[Barry]

I have a 2018 5.0 GT auto trans. Mustang and was wondering if any one has noticed that after driving and stopping the engine for a short while, then restarting the motor with the temp. gauge still on the half way position between cold and hot, that the rev. counter hovers around 1000 rpm for a short while before it drops back to the cars normal idle speed (ie. below 1000 rpm)? It appears to reduce in revs after about 5 seconds or more until it sorts itself out.

My issue is that I have noticed that when selecting reverse or drive while stationery and foot on the brake at the higher revs (my foot is definitely not sitting on the accelerator pedal!) with the motor at normal operating temp. that the shift into reverse or drive is much more severe or aggressive than I would have expected. The shift severity is a lot more noticeable even than moving from park to reverse/drive with a cold motor first thing in the morning with the choke on and running at about the same rpm's 1000-1200?

Maybe this is normal, just didn't know if I should idle for a longer period with a warm motor before moving the selector from park?

Any advice would be appreciated. thank you.

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[kent0464]

In my F150 with the 10 speed auto I’ve found that waiting until the computer loads and the revs drop to normal the truck is much better behaved. If I just jump in, start it and go immeadiatly it does weird shit like yours does, as well as running funny for 30-60 seconds or jumping multiple gears. Think of it as booting up your desktop or smart TV....just doesn’t work right until loads and runs through the start-up procedures.

 

[Barry]

In my F150 with the 10 speed auto I’ve found that waiting until the computer loads and the revs drop to normal the truck is much better behaved. If I just jump in, start it and go immeadiatly it does weird shit like yours does, as well as running funny for 30-60 seconds or jumping multiple gears. Think of it as booting up your desktop or smart TV....just doesn’t work right until loads and runs through the start-up procedures.

Thanks Kent, good advice. I'll give it a try in future.

 

[Barry]

An update on my issue posted 26 October. My Ford dealer arranged for the Ford technical officer, who visits each 3 months, to inspect my vehicle at their workshop, As the harsh gear shift has only happened on two occasions in 8000 klm's he thought it was a result of the engine / transmission electronics re setting itself for different driving conditions. I usually drive the car in Sports mode but had driven it in Sports + mode for a while before the harsh gear change occurred. I was concerned that the harsh shift could cause strain on the transmission or drive train, however the Ford expert didn't think this would be an issue. Apparently, there is some limiting device fitted that prevents this from happening.

 

[Cobra Jet]

An update on my issue posted 26 October. My Ford dealer arranged for the Ford technical officer, who visits each 3 months, to inspect my vehicle at their workshop, As the harsh gear shift has only happened on two occasions in 8000 klm's he thought it was a result of the engine / transmission electronics re setting itself for different driving conditions. I usually drive the car in Sports mode but had driven it in Sports + mode for a while before the harsh gear change occurred. I was concerned that the harsh shift could cause strain on the transmission or drive train, however the Ford expert didn't think this would be an issue. Apparently, there is some limiting device fitted that prevents this from happening.

So the Ford Dealer didn’t do anything but tell you that and send you on your way?

What they should have done, at least the bare minimum, would have been to reflash the 10R80 TCM with the latest software version to see if that would resolve the harsh shifts. The harsh shifts is a common 10R80 concern and usually the reflash has been a reported improvement by other owners.

 

[Deleted member 35644]

If you have "bad code", you'll eventually get a wrench light. On several occasions, fully warmed up, re-started after 15-20 minutes, waited for it to settle at idle, went from P to D, the car shot forward like a bull out of a chute. It SLAMMED into gear, exactly like a 1500 rpm clutch-drop in a manual. Strangely, the wrench light came on while driving on the highway. They re-flashed, and it's never lurched since, but some of its indecisive behavior remains. Point is, you may have to wait until it sets a code before they'll do anything meaningful.

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