2.3 Manual... Rolling in Gear?

[Moto26]

At the Moab Off Roadeo, our instructor hammered on us that even in A/T Broncos, you should always, always, always use the E brake any time you get out of the vehicle on the trail. I imagine this would especially be the case with M/T. So consider parking on any grade to be the same as parking on the trail…

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[redone17]

I would like to see Ford update the software to have the parking brake automatically engage when the truck is shut off in any gear or neutral.

Wonder if Forscan or FDRS can handle that change...

 

[BigHoof]

I would like to see Ford update the software to have the parking brake automatically engage when the truck is shut off in any gear or neutral.

So what happens when you have a parking brake glitch like has been posted on here and then you can’t apply it? Enough with the electronics. Just give me a manual lever.,

 

[Gassyjack]

I think about if the ebrake fails also. Have a steep trail with a gate halfway up that you have to stop on steep, rocky incline and get out and open. I haven’t driven it yet but it’s been on my mind. If the ebrake fails the bronco will be totaled.
Usually some is with to open the gate, but can’t count on it.

 

[lapazleo]

Many people have replied about driving a manual and never having this problem. How many people have driven a 3500 lb vehicle with a 122 cubic inch engine? This is the reason the vehicle roll’s spinning the engine.

First the the Bronco weighs 4500 plus second it's compression not displacement turbo charged engines have have lower compression by design.

 

[lapazleo]

Always park on the level problem solved LOL .

 

[BigHoof]

First the the Bronco weighs 4500 plus second it's compression not displacement turbo charged engines have have lower compression by design.

10-1 CR is not really low. 2.3 or 2.7 L though is not enough volume to hold back the weight.

 

[JakeL]

Always park on the level problem solved LOL .

@lapazleo I'm not sure what part of Indiana you're from, but I grew up in Northern Indiana where there is PLENTY of level parking - Southern Indiana is another matter

I'm not an automotive expert, but it seems to me that the more efficient the drivetrain is the easier it would be to backdrive the transmission. All else being equal, design and manufacturing improvements that have reduced friction in the system make it easier for this situation to occur. But the previous weight and compression comments certainly explain help why this is first-time experience for folks. I'll be sure to exercise more care when I receive my M/T Bronco next month!

 

[BroncoAZ]

So what happens when you have a parking brake glitch like has been posted on here and then you can’t apply it? Enough with the electronics. Just give me a manual lever.,

I agree 100% with the manual lever, but the software solution is something that could be done without major modification. Even if there was a manual handle that activated the electric parking brake it would feel more intuitive than the current button.

 

[Jimmiee]

First the the Bronco weighs 4500 plus second it's compression not displacement turbo charged engines have have lower compression by design.

Typo on the 3500 and my point exactly. A very heavy vehicle with a very small displacement engine.

 

[bloominguez]

So I parked my 2.3 Manual Bronco outside a shop yesterday, left it in 4th like I always do, but forgot to put on the emergency brake. This is uncharacteristic of me and as far as I can recall the first time I've done it in the vehicle. I live on a fairly steep hill so I use it regularly.

The shop had maybe a 2 degree slope, nothing really. I hopped out and went inside. My wife was still sitting in the "parked" vehicle. She called me within about 3 minutes to say the Bronco had rolled into a ditch in front of the Bronco. Thankfully it was a slow roll into a low ditch. Put the bumper up against the side of a hill and sat there.

I can't believe I read this whole thread and didn't see any comments about how your future ex-wife just sat in the car and let it roll into a ditch. Wow. I expect more from this forum!

 

[atimberwolf]

I can't believe I read this whole thread and didn't see any comments about how your future ex-wife just sat in the car and let it roll into a ditch. Wow. I expect more from this forum!

After 20 years we're pretty committed to each other, and the fact that there was no damage helped a lot.

 

[atimberwolf]

I came searching for this issue. I got my 2022 2.3l manual Bronco the last week of November and my driveway has a small slope. I always use the ebrake but my husband leaves in 1st gear. He rarely drives my car but it has rolled out of our driveway 4 times. I made an appointment with ford to have it checkedbout the first time it happened but it took 3 months to get it in. The dealership called yesterday and are having ford field service engineers come in to investigate.My husband and I have driven manuals all our lives and never had this issue. I’m also a quality engineer at a transmission plant and think this may be going the way of a recall. Did you get resolution?

I've created the habit of putting it in C or R depending on the angle I'm parked on and then pulling the e-brake. Since then I haven't had another rolling incident. Wasn't excited to create new habits with a manual, but it seems to be working.

I'd be interested to hear what you discover through @Ford if they get back with you.

 

[MsPickles]

Maybe this will help someone, but the compression ratios don't come in to play with a engine that is not running. The blow-by that happens with all engines will leak out any air of any cylinder over a period of time. That time is determined by the fit of the rings to the cylinder walls. So any vehicle on an incline with no mechanical drivetrain lock will continue to rotate as the air leaks out of every cylinder that come in to the start of a compression cycle. Just the nature of these engines.

But what does come in to play is friction. Friction of the ring surfaces against the cylinder walls and the diameter and number of cylinders. I do not have the thickness of the rings to calculate the surface area of the rings, but the length of of the cylinders can be calculated from the basic engine specs.

The 2.3 bore is 87.6mm. Total circular length of all the cylinders is 43.4".
The 2.7 bore is 83.1. Total circular length of all the cylinders is 61.6"

2.3l Bore diameter = 87.6mm, circumference = 275.1mm, * 4 cylinders = 1,100.4mm | 43.3"
2.7l Bore diameter = 83.1mm, circumference = 260.9mm, * 6 cylinders = 1,565.4mm | 61.6"

Difference = 465mm | 18.3"

So the 2.3 has 18.3 less inches of contact length to "hold" an engine from spinning over, less frictional forces. The older vehicles with V8s had even more frictional forces holding a vehicle in place wen left in gear. Plus with the transmission being in 4th gear, that provided no transmission gear reduction, 1:1, to add to the ease of the vehicle moving in gear.

So in the end, more cylinders does increase the frictional holding forces for an engine turning over. Obviously this is a simplified calculation, and a more accurate one could be had, but one would need all the ring thicknesses for an area calculation and the spring force of the rings to the the cylinder wall, then the actual frictional coefficients could be calculated. But the end result is that with todays smaller and less cylinder engines, there will be less friction to hold an engine from spinning without a mechanical lock of some kind (parking pawl or e-brake).

 

[Jimmiee]

Very well said MsPickles!

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