Uncommanded acceleration in 4L

[Fly2Win]

I did my first real off-road day with my 6 week old Bronco at the Anthracite Outdoor Adventure Area in PA coal country. Me and 4 Jeeps hit a bunch of green trails.

The Bronco is amazing and performed well throughout the day. However, there were a half dozen times when I experienced an uncommanded acceleration.

I have a Black Diamond 2.7 Auto, 2D, SASQ, MID Bronco.

While running through the woods on mild rock trails (softball or smaller sized rough mining debris with the occasional slab to set a wheel on) in 4L and in D (not M1 or M2) at just a couple MPH, I would let off the accelerator to let the engine slow me down, and it felt like I had hit the gas pedal. Enough so that I quickly stabbed the brake pedal to stop it.

Has anyone else experienced this? I feel like it is controllable but is a bit of a surprise when it happens.

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[‘21OBX]

You didn’t hit the trail cruise button did you? It will keep you going.

 

[Fly2Win]

No, That was off. Good question, though. That was the first thing I checked.

 

[dgorsett]

My bronco doesn't do it, but my f250 does when in 4L first gear headed downhill. It seems like it's trying to burn off fuel loading up on a steep down grade. It actually will go slower downhill in second M mode.

 

[Merc4x4]

Maybe it shifted up a gear or two on you? Which GOAT mode were you in?
I've been using M&R and RC modes to take advantage of transmission/throttle/steering tuning you can't set manually. I could see the transmission up-shifting in Normal mode for better fuel economy vs holding gears longer in Sport/Sand/Rock Crawl.

 

[AK SNO RIDER]

If it wasn't trail control ny guess would be it was shifting. You know that "kick" the trans does when slowing to the stop on the 2-1 shift? If it was doing that in low range it would be extra noticeable.

 

[Fly2Win]

Maybe it shifted up a gear or two on you? Which GOAT mode were you in?
I've been using M&R and RC modes to take advantage of transmission/throttle/steering tuning you can't set manually. I could see the transmission up-shifting in Normal mode for better fuel economy vs holding gears longer in Sport/Sand/Rock Crawl.

Hmmm, I was in Normal mode. It could have been a shift now that you mention it. Hard to tell sometimes. I’ll try RC and turn off the rear locker next time. Thx.

 

[kevin.gt]

I could see the transmission up-shifting in Normal mode for better fuel economy vs holding gears longer in Sport/Sand/Rock Crawl.

This It's happened to me in 4L Normal and I'm pretty sure it was an unexpected upshift. Makes sense too. Down hill, picks up speed increasing rpm, triggers an upshift

 

[Fly2Win]

If it wasn't trail control ny guess would be it was shifting. You know that "kick" the trans does when slowing to the stop on the 2-1 shift? If it was doing that in low range it would be extra noticeable.

Yes, I have felt that. First stop pulling out of work is a little downhill and I sometimes feel it lurch a little forwards. I can see where it would be more pronounced in 4L.

 

[AZMikeL]

I recall this happening a time or 2 in 4L as well. Can't recall if I had it in Manual mode or not though. I'll try to remember to test it out next time I'm in 4L.

 

[darkscion0]

I posted about this before but I've experienced something similar. The shift from 1st to 2nd can be really jarring, to the point that I shift up manually when offroading.

 

[SeldomSeen]

I did my first real off-road day with my 6 week old Bronco at the Anthracite Outdoor Adventure Area in PA coal country. Me and 4 Jeeps hit a bunch of green trails.

The Bronco is amazing and performed well throughout the day. However, there were a half dozen times when I experienced an uncommanded acceleration.

I have a Black Diamond 2.7 Auto, 2D, SASQ, MID Bronco.

While running through the woods on mild rock trails (softball or smaller sized rough mining debris with the occasional slab to set a wheel on) in 4L and in D (not M1 or M2) at just a couple MPH, I would let off the accelerator to let the engine slow me down, and it felt like I had hit the gas pedal. Enough so that I quickly stabbed the brake pedal to stop it.

Has anyone else experienced this? I feel like it is controllable but is a bit of a surprise when it happens.

Yes. Just started new thread.

 

[Blaze The Bronco]

This has happened to me several times. Sometimes it happens when it is shifting but it has happened a couple times when it is in first gear and not shifting. A bit concerning. I have always been going down something steep when it has happened.

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