Transmission down shift clunk, FIXED

[FJMainiac]

In a previous post, I described a harsh downshift clunk when slowly coming to a stop. Most noticeable in stop and go traffic. Sometimes felt like two bumps, one around 3-5 mph, and the second just when I come to a full stop. I was not sure if this normal for that type of transmission or if something else was wrong.

I was at the dealership for 10k service, and went for test drive with tech to demonstrate the issue. The tech said no mechanical issue, no problem codes, and no software update (yet) but cleared the transmission memory.

Now the shifting is absolutely smooth, no harsh downshift at all.

While I was there I also had the break squeal repair (known issue).

 

[Michael T]

In a previous post, I described a harsh downshift clunk when slowly coming to a stop. Most noticeable in stop and go traffic. Sometimes felt like two bumps, one around 3-5 mph, and the second just when I come to a full stop. I was not sure if this normal for that type of transmission or if something else was wrong.

I was at the dealership for 10k service, and went for test drive with tech to demonstrate the issue. The tech said no mechanical issue, no problem codes, and no software update (yet) but cleared the transmission memory.

Now the shifting is absolutely smooth, no harsh downshift at all.

While I was there I also had the break squeal repair (known issue).

So what was done to stop the harsh trans shifts, as mine does this as well, and dealership acknowledged it when they fixed my brake squeal?

 

[FJMainiac]

The description on the paperwork states "Technician verified harsh downshift into first gear when coming to a slow stop. Technician cleared transmission memory."

 

[Michael T]

The description on the paperwork states "Technician verified harsh downshift into first gear when coming to a slow stop. Technician cleared transmission memory."

So they reset the transmission to relearn driving habits?

 

[FJMainiac]

Correct, the tech mentioned something about the software learning driving habits and reset apparently "unlearned" whatever was causing the hard downshift to 1st.

 

[Michael T]

Correct, the tech mentioned something about the software learning driving habits and reset apparently "unlearned" whatever was causing the hard downshift to 1st.

Will have to ask for this at 10k mile service

 

[Bluegill]

Will have to ask for this at 10k mile service

Me too

Although it might re-learn the same stupid harsh downshift.

 

[Snooperstyle]

Cars are just too damn complicated these days. It freaks me out that computers control critical things like this.

 

[Bluegill]

I drove my 1998 Porsche with 175,900 miles on the odometer yesterday. If there's a clunky downshift, it's completely my fault. It's such a simple joy to drive. The radio has been broken since November of 2017 when my then-2.5-year-old stuffed the CD player full of coins from the ashtray and I haven't bothered to fix it.

 

[El Chorizo]

Cars are just too damn complicated these days. It freaks me out that computers control critical things like this.

I had to remind someone that things are just different, in all regards. Complex, yes, but with that complexity we get a lot of improvements.

I reminded him that my 1991 Mustang, with the 5.0 V8, that we all remember... sounds so good. Muscle car. 225 HP. Rated higher back then than it would be now.

So the tech can bring some unfortunate downsides... but you can get 225 HP out of a 1.2L now a days. So technology has also brought us amazing things in cars.

Just something to keep in mind

 

[Redbird99]

Cars are just too damn complicated these days. It freaks me out that computers control critical things like this.

It's a gradual, but logical, progression when when you consider that cars with ECM's have 'learned' things about the drivetrain for a long time.

As an example, as carbon builds up in the throttle body, the throttle body position sensor adjusts to compensate. It's not entirely evident that this 'memory' is happening, until it is erased (by, for example, a dead battery) This can cause drivability issues - stalling and low rpm stumbling- which will remain until the throttle body is cleaned.

I'm grateful for all that computers have brought to the table, especially for things like adaptive cruise control, lane assist, and all that stuff that optimizes engine power and torque.

Says the guy who enjoys driving and setting the timing on his 1970 GTO.