Engine Braking Pros and Cons

[AndySpill]

On the JL[U] specifically, is the wear and tear on engine and transmission components of manually downshifting (an automatic) to in part--in collaboration with the foot brakes--slow down the vehicle not worth it? Would it be better--assuming this engine braking isn't done in excess--to sooner wear out the brakes and replace them (a relatively minimal service item) than spare the brakes and put more of the deceleration efforts on engine's compression and transmission's innards?

Certainly we're working against the forces of inertia here when accelerating a vehicle but should we normally--big hill, lots of weight, and need to control excess speed notwithstanding as a good reason to downshift--leave deceleration to the brakes?

Thoughts?

TIA

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[Ratbert]

I wouldn't think that there'd be significant wear on the transmission / engine by downshifting, but I'm no expert.

The big risk is in overheating your brakes to the point of them failing. That can be deadly.

 

[Tethmes]

As long as you're properly rev matching your downshifts there is no chance of damage to the vehicle.

 

[NoahVD]

Brakes are much cheaper to replace than an engine or transmission. Let them do the work.

 

[Opus]

Living in Flatlandia for most of my adult life, I learned the hard way that engine braking is necessary on mountain roads.

 

[2nd 392]

If not for engine braking likely another wooden cross would be on the side of (old) Pacheco Pass when the first new trailer with “anti-skid” brakes became “anti-brakes”.
Common sense applies- mountainous area, heavy load, or towing use to not overheat brakes.

 

[Heimkehr]

On the JL[U] specifically, is the wear and tear on engine and transmission components of manually downshifting (an automatic) to in part--in collaboration with the foot brakes--slow down the vehicle not worth it?

Would it be better--assuming this engine braking isn't done in excess--to sooner wear out the brakes and replace them than spare the brakes and put more of the deceleration efforts on engine's compression and transmission's innards?

Brake pads are considerably less expensive than are transmission components.

Using engine compression to slow a vehicle down can sound cool, but that resistance has to be absorbed and processed by something. Better that that something be the 2 or 3 components per wheel that were expressly designed with that function in mind.

 

[Powelligator]

Maybe if you're going down a hill that's a mile or so long, sure, go ahead and use the service brakes. But if you're going down a "real hill", like I-70 from the Eisenhower Tunnels down into the Denver metro area, please, please, please downshift and let engine braking do most of the work. Think of it as a unique stretch of the interstate highway system that requires a unique way of driving, not found anywhere else in the USA.

 

[DubaiMarauder]

Maybe if you're going down a hill that's a mile or so long, sure, go ahead and use the service brakes. But if you're going down a "real hill", like I-70 from the Eisenhower Tunnels down into the Denver metro area, please, please, please downshift and let engine braking do most of the work. Think of it as a unique stretch of the interstate highway system that requires a unique way of driving, not found anywhere else in the USA.

You've obviously never heard of Donner Pass or Wolf Creek Pass or Vail Pass. There are plenty of long, winding downgrades in the US. Mostly in the Rockies, but can also be found in the Owyhees in Oregon, the Blue Ridge Mountains as well as the Appalachians (specifically W. Va. and PA) and the Catskills in New York.

To OP, there is nothing wrong with using your engine as a brake or retarder to control speed. Truckers do it all day every day. I drove a manual car for 6 years and never had any engine troubles due to downshifting engine braking. The only way you're going to hurt anything in the drivetrain is by letting your RPMs get too high. Avoid that and you're golden.

 

[Ratbert]

Brakes are much cheaper to replace than an engine or transmission. Let them do the work.

Try descending something like Pike's Peak with that mentality. Your brakes will not survive. That's when your passengers start "commenting" on your reluctance to downshift.

 

[2nd 392]

You've obviously never heard of Donner Pass or Wolf Creek Pass or Vail Pass. There are plenty of long, winding downgrades in the US. Mostly in the Rockies, but can also be found in the Owyhees in Oregon, the Blue Ridge Mountains as well as the Appalachians (specifically W. Va. and PA) and the Catskills in New York.

To OP, there is nothing wrong with using your engine as a brake or retarder to control speed. Truckers do it all day every day. I drove a manual car for 6 years and never had any engine troubles due to downshifting engine braking. The only way you're going to hurt anything in the drivetrain is by letting your RPMs get too high. Avoid that and you're golden.

When you’re flying down the old Pacheco Pass with ~80K lbs using all the 2 or 3 lanes available, wheels off the ground in curves and the tach pegged F’ the Cummins. It and I both survived to call the shop and warn them to put the new trailers OOS until the glitch was corrected. I turned off the air and released the brakes on it and finished the run with brakes on 4 axles.

 

[Phrank]

When you’re flying down the old Pacheco Pass with ~80K lbs using all the 2 or 3 lanes available, wheels off the ground in curves and the tach pegged F’ the Cummins. It and I both survived to call the shop and warn them to put the new trailers OOS until the glitch was corrected. I turned off the air and released the brakes to it and finished the run with brakes on 4 axles.

Wolf Creek Pass, way up on the Great Divide. Truckin' on down the other side.

 

[Fast-n-Furious]

I use engine brake frequently especially the downhills near school zones.

 

[Ratbert]

You've obviously never heard of Donner Pass or Wolf Creek Pass or Vail Pass.

You might be showing your ignorance in suggesting that @Powelligator hasn't been down those and worse passes. There are plenty of extremely steep / long roads in our area.

 

[Powelligator]

You've obviously never heard of Donner Pass or Wolf Creek Pass or Vail Pass. There are plenty of long, winding downgrades in the US. Mostly in the Rockies, but can also be found in the Owyhees in Oregon, the Blue Ridge Mountains as well as the Appalachians (specifically W. Va. and PA) and the Catskills in New York.

Yes I've heard of those passes, I was using the Eisenhower as only one example. You missed my point entirely. I was really pointing out that for people who live in places that don't really have high hills and really long downhill grades, like the beaches of california or the hills of Pennsylvania, that out here, at least, there are some really good reasons for using engine braking and staying off the brakes.

I have seen the results of, and the white crosses on the side of the road after, when drivers have only relied on their service brakes descending some of the passes out where I live. I'll go ahead and put this out, flame suit on, but using your service brakes and engine braking are two tools that a driver can use to get down off a big hill. If you only lock yourself into using one of those two tools because it's too expensive to replace a clutch or transmission, well then you're doing it wrong. End of rant.

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