Engine braking in an Automatic Jl

[Rahneld]

A couple hundred feet from a red traffic light, traveling at a relatively fast speed relative to the distance from that light that will mandate slowing the rig beyond simply coasting and letting friction do its thing, are there cons to downshifting and braking versus simply breaking?

Thanks.

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[Gallagher]

pad and rotor wear is cheaper than transmission wear!

 

[GreyFox]

Man, I haven't owned a manual since the early 90's, but I would just throw it in neutral and brake.

 

[spurly]

You're really not going to wear out your transmission. And the computer won't let you downshift if it's going to hurt the engine. Sometimes in hard braking applications I'll downshift and brake at the same time. Samething I do on my bike too.

 

[cosine]

i let the computer control the motor and trans. since the throttle response is quick, i use the brakes less than normal. my brother drove my jl thru the smokey mountain in tennessee and hardly used the brake going down hill.so there shouldnt be any harm done. i drive a ram pro master van for work with the same set up. 16k miles and no issues. beside that, fca wouldnt build this setup if it was going to be a big issue.

 

[Rahneld]

pad and rotor wear is cheaper than transmission wear!

I get that Jeff. And yet the engine, through the transmission, overcomes the forces of inertia to get the rig moving. That's force again the transmission too.

Why would it be any different using the engine to slow down the vehicle overcoming the same forces of inertia only in the opposite direction?

Maybe what you're saying is that doing this is like putting 50K mileage wear on the transmission for a rig with only, say, 30K mileage on it.

Thanks.

 

[spurly]

I'm actually surprised at how much the 8speed downshifts itself when coming to a stop or slowing down. Almost like it's trying to engine brake itself. It's very noticeable too compared to other new vehicles.

 

[higbyz]

pad and rotor wear is cheaper than transmission wear!

Yeah,no question

 

[apb]

I'm actually surprised at how much the 8speed downshifts itself when coming to a stop or slowing down. Almost like it's trying to engine brake itself. It's very noticeable too compared to other new vehicles.

When I was planning on getting the new Jeep I was dead set on getting a manual. Then I discovered the JL's had the 8 speed ZF transmission and that immediately changed my mind, this transmission is world class good.

 

[DaltonGang]

A couple hundred feet from a red traffic light, traveling at a relatively fast speed relative to the distance from that light that will mandate slowing the rig beyond simply coasting and letting friction do its thing, are there cons to downshifting and braking versus simply breaking?

Thanks.

You threw me when you spelled "Breaking", instead of "Braking". One is good for the engine, one is bad.

 

[Rahneld]

You threw me when you spelled "Breaking", instead of "Braking". One is good for the engine, one is bad.

..an unintended double entendre of smart phone autocorrect and lack of reading glasses at the time I suspect!

 

[Buckster]

With this question in mind, I ran in manual mode to work this morning and tried downshifting as a means to help slow the Jeep. I honestly could tell no real benefit. Without the auditory feedback from the exhaust, I was constantly looking at either the tach or the gear indicator to figure out what gear I was in. Add to that the fact that the orientation is reverse from my last car (push forward to downshift, pull back to upshift) then I was constantly focused on that and not my driving. May be no harm in driving in this manner, but I can't come up with a reason to do it. With a manual or sports car with a sequential gear transmission, sure, downshift when slowing to ensure you are always in the correct gear, but the Jeep has decent brakes so I'll let the ZF tranny do its thing in full auto.
Just my humble .02.

 

[ZEN357]

pad and rotor wear is cheaper than transmission wear!

I agree! Just drive the thing as you normally would. My Grandfather who was a mechanic always said "You treat your car like your horse. You wouldn't beat you horse, so don't beat on your car."

 

[Rahneld]

I agree! Just drive the thing as you normally would. My Grandfather who was a mechanic always said "You treat your car like your horse. You wouldn't beat you horse, so don't beat on your car."

makes sense...besides, if you want to know a thing or to about "wheeling," ask a man who comes from a place that bears its namesake

 

[Headbarcode]

IMHO, the biggest savings to wearable items would be clutchless shifting a manual transmission. Back in my single digit years, my trucker than mechanic father taught me how on various motorcycles, sports cars, pickups, and tractor trailers all a mixture of non-synchro and synchro mesh. One of the less obvious benefits, that he let me realize on my own, is that it builds the habit of not racing up to red lights with the morons and also being more situationally aware because you require more distance to slow and stop. He used to call it "riding the lights".

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