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-   -   Auto vs. Manual - Technical Please (http://www.wranglerforum.com/f274/auto-vs-manual-technical-please-166345.html)

kcraw 06-12-2012 03:15 PM

Auto vs. Manual - Technical Please
 
There are already a bunch of threads discussing which is "better" and whatnot, so please let's keep this about technical differences.

It's been a long time since I've driven an automatic, and I've never driven anything but a stick off road. I'm considering moving to an automatic when ordering a 2013, but I'm wondering what the non-obvious differences will be.

For the record, driving a stick is second nature at this point so I'm not worried about which is "better" from a "which is easier" standpoint, nor do I worry about rush hour traffic or crawling in a stick--I'm used to it. For day to day driving, I enjoy rowing my own gears.

What I'm wondering is how does the HSA compare to engine braking?
How do the crawl ratios compare in 4-lo?
For anyone who has driven sticks forever and then moved to an auto, what's it like driving off road with one in a variety of terrain?

An auto w/ remote start would be nice sometimes for the convenience, but at almost $1.5k I probably would stick with a stick if represented a technological step backwards are far as capability or durability. On the other hand, if it offers the technical advantage off road (along with the obvious convenience on-road) then it's well worth it.

If I missed a thread on point for this topic I apologize.

kik 06-12-2012 03:24 PM

Technically, it's personal preference. Simple as that. All discussions on this topic have come down to subjective personal preference. Take your pick.

kcraw 06-12-2012 03:31 PM

With all due respect, I think crawl ratios and HSA's performance as compared to engine braking are somewhat objective facts.

I have no strong preference on stick vs. auto on a Jeep... so I'm looking for objective facts on both NOT personal preferences, which is what every other thread I've read has been.

kjeeper10 06-12-2012 03:39 PM

Quote:

Originally Posted by kcraw
With all due respect, I think crawl ratios and HSA's performance as compared to engine braking are somewhat objective facts.

I have no strong preference on stick vs. auto on a Jeep... so I'm looking for objective facts on both NOT personal preferences, which is what every other thread I've read has been.

I think no matter how you look at it. It's still personal preference.

AMilton 06-12-2012 03:46 PM

While I don't have any technical data to offer, I can say from experience that driving an auto after being used to a stick takes some getting used to.
Deceleration when letting off the gas is probably that most awkward thing for me. Off road is much easier as I can lean out the door and look at the rocks and line up better.
After jeeping in both stick and auto I think auto is more user friendly but I would be happy with either.
I'm sure you will be happy with which ever you choose.

SilverSport 06-12-2012 03:56 PM

While crawl ratios aren't exactly identical between the automatic and 6 speed, they will be similar. HSA = Hill start assist. Were you thinking "hill descent control"? I believe HDC is offered only on automatics. I learned to 4 wheel long before hill descent control came along.

You ask for objective facts but in the end you will still make a personal choice. :whistling:

panthermark 06-12-2012 04:13 PM

If you want crawl ratio's, go here:
Gear Ratio Calculator

kcraw 06-12-2012 04:59 PM

Quote:

Originally Posted by SilverSport (Post 2465540)
While crawl ratios aren't exactly identical between the automatic and 6 speed, they will be similar. HSA = Hill start assist. Were you thinking "hill descent control"? I believe HDC is offered only on automatics. I learned to 4 wheel long before hill descent control came along.

You ask for objective facts but in the end you will still make a personal choice. :whistling:

:facepalm: Yeah, that's what I meant. I know it's some sort of braking system, but no idea how it works. I almost accidentally typed "breaking system" and that's part of what I wonder about. Is it generally reliable, and is it used the same way engine braking is used heading down a hill?

Also, thanks for the gear ratio link. Very useful.

kcraw 06-12-2012 05:01 PM

Also, I appreciate the info. I know I'll have to make a decision based on preference, but I don't think the dealership is gonna let me take an auto Rubi for some rough off-roading to see how I like it, so I'm trying to make an educated guess.

daggo66 06-12-2012 05:02 PM

Crawl ratios are a factor of axle gears and tc gears. Auto vs. Manual is not much of a factor. Hsa has nothing to do with engine braking.

MacCTD 06-12-2012 05:08 PM

The new 5 speed auto has hill decent control which I would assume is some type of torque converter lockup that allows engine braking same as a standard. The option cost for the auto on my '12 was $1125.

kcraw 06-12-2012 05:18 PM

Quote:

Originally Posted by daggo66 (Post 2465802)
Crawl ratios are a factor of axle gears and tc gears. Auto vs. Manual is not much of a factor. Hsa has nothing to do with engine braking.

Yeah, I meant HDC. Someone already called me out on that particular :facepalm:

As for crawl ratio... auto vs. manual doesn't matter, but first gear ratios do. So I'm answering my own question now thanks to the gear ratio link provided, but with 33" inch tires the final "crawl" ratio for the manual is 73.14:1 compared to 58.88:1 for the 5-speed auto.

First gear ratio is 4.46 and 3.59, respectively. Not a huge difference, until you start putting a multiplication symbol on either side of it. It's still a huge improvement over the 42RLE with a first gear of 2.8 resulting in a first gear final ratio of 45.92:1.

How important is crawl ratio? I don't know, guess we're back to personal preference. :whistling:

JeepHerz 06-12-2012 05:23 PM

Just make sure to get 3.73 gears minimum when you order. I may be mistaken but I think some manual JK owners have pretty much lost 6th gear with 35s. Just don't get stuck with 3.21s (like moi).

FYI- 2012+ JKs have "manual" mode in the automatic. Clutchless shifting. When I am feeling Sporty-er- I drive my JK in manual mode and shift. Whenever I enter a California freeway- I pop it right back into auto. (The traffic is mind-boggling). You can crawl in 4LO by shifting, or keep it in automatic. My only complaint is that on a broad power-banded Jeep its hard to tell what gear you're in. You can drive around in a Jeep at 30 MPH in 1st and hardly notice. I find myself checking the dash alot to see where I am at since there isn't the "feel" of a shifter.
On the Hill Descent- its weird. It works, but its weird. The gas pedal and the brake operate totally without you. (You can of course still hit the brakes.). Like someone else said- its not necessary for crawling. Only used it once to see what it does. We have fire roads/trails here that take you up mountain peaks- its more handy on a long descent than anything else. Lest the stupid human ride the brakes too much and toast them.

kcraw 06-12-2012 05:24 PM

From the Jeep site:

Hill Descent Control
Hill Descent Control with grade sensing allows a smooth and controlled hill descent on rough or slippery terrain without the driver needing to touch the brake pedal. This system applies the brakes to each wheel individually when needed to reduce forward motion while negotiating down steep grades.

That's why I'm slightly concerned. However, BLD seems to work pretty well. What I'm wondering from someone with experience is if BLD is to Lockers as HDC is to Engine Braking as far as performance, or if it is equally more equally effective.

The functionality of putting it into a lower gear versus pushing a button matters not to me, I only care how well it performs.

Dozer13JK 06-12-2012 05:32 PM

Is it just me or are todays age Jeeps more often auto now than manual? The dealership I was at had a good bit more selection in auto vs that of manual.

kcraw 06-12-2012 05:35 PM

Also I have no idea how a torque converter comes into play with anything I said above, because I don't really know what I'm talking about it.

strider_mt2k 06-12-2012 05:37 PM

Quote:

Originally Posted by Dozer13JK (Post 2465897)
Is it just me or are todays age Jeeps more often auto now than manual? The dealership I was at had a good bit more selection in auto vs that of manual.

Unlimited automatics are the popular sellers.

DFW6ER 06-12-2012 05:39 PM

Quote:

Originally Posted by Dozer13JK (Post 2465897)
Is it just me or are todays age Jeeps more often auto now than manual? The dealership I was at had a good bit more selection in auto vs that of manual.

This reflects the preference of society at large. More and more people are hitting 16 who never have and never will learn to drive MTX and the few of us who do aren't getting younger. Add to that that more folks live in congested city traffic with horrendous stop and go 90 minute commutes and the very impressive gains ATXs have gotten in fuel efficiency and you see why this is the case.

Dozer13JK 06-12-2012 05:42 PM

Quote:

Originally Posted by strider_mt2k (Post 2465914)
Unlimited automatics are the popular sellers.

Very true strider. Especially the Unlimited 4-doors. When these were introduced in '07 I never saw them becoming so popular as they have today.

Dozer13JK 06-12-2012 05:44 PM

Quote:

Originally Posted by DFW6ER (Post 2465925)
This reflects the preference of society at large. More and more people are hitting 16 who never have and never will learn to drive MTX and the few of us who do aren't getting younger. Add to that that more folks live in congested city traffic with horrendous stop and go 90 minute commutes and the very impressive gains ATXs have gotten in fuel efficiency and you see why this is the case.

I see where you are coming from. Sad to see that the manual transmissions seem to slowly be fading away.

keschete 06-12-2012 05:46 PM

I can tell you about the daily driving aspect. I have a 6 speed 2009 JK. I love it because when I got it, it was much more responsive than the auto.

I have driven the Auto and Manual in the 3.6 liter on the 12 and I think the auto is very responsive, the 6 speed is even more responsive. I like speed and I chirped the damn tires on the sport I drove with the 6 speed.

No question for me. I like the control I have with a manual. Just my 2 cents.

kjeeper10 06-12-2012 05:47 PM

Stick-4-life :thumb:

4Jeepn 06-12-2012 05:56 PM

I have had a few jeeps.. most in sticks a few in auto's.. here is what I have experienced. A lower crawl ratio(higher number) in most cases will give you more control over the trail your own. That being said, with no fancy computer crap on the jeep just the driveline a stick will be better going down a hill than an auto with no other factors, going up a hill the auto will have a slight advantage as it will not stall out, and starting and stopping will be easier. You can limp home with a stick with an auto not so easy. Autos can die if they get to much mud or water sucked it.. a stick can press on. That being said.. I like my current automatic.

Kelsey73 06-12-2012 05:57 PM

I like to drive manual trans and after selling my challenger I do miss have a MTX around and am Always looking for a good used jeep with a manual now. Ideal would be an '11 rubi 4 door

namedperil 06-12-2012 06:13 PM

The auto will be running ~100 rpm faster on the interstate... potentially saving an expensive re-gear with 35"s, auto will have a better resale market when you sell, and you can shift gears in the water.

Manual's are fun to drive and get ~1mpg better at speed.

I'm trying to make the same decision myself and leaning towards the auto.

JeepHerz 06-12-2012 06:17 PM

Quote:

Originally Posted by keschete (Post 2465945)
I can tell you about the daily driving aspect. I have a 6 speed 2009 JK. I love it because when I got it, it was much more responsive than the auto.

I have driven the Auto and Manual in the 3.6 liter on the 12 and I think the auto is very responsive, the 6 speed is even more responsive. I like speed and I chirped the damn tires on the sport I drove with the 6 speed.

No question for me. I like the control I have with a manual. Just my 2 cents.

The 2012s also have a 5 speed automatic versus a 4 speed in the prior models- and it does make it feel alot more responsive. (80 horsepower helps a little too). Its why I waited on the 2012 JK everyone hates so much.
I had an old manual TJ- and it was a ton of fun. If I didn't live in the top 10 worst cities for traffic- I'd have gotten a manual.

rics1997 06-12-2012 06:46 PM

Even though many have mastered the manual transmission, the fact is doing rock crawling need percise control with one foot on the gas and the other on the brake. With the JK at least you have anti-stall but it is still a lot easier with an automatic not to mention the forward momentum of the anti-stall can't over come an initial vertical climb. Also the torque converter adds the needed torque in certain situations. Of course even if you stall, in most cases it's not the worse thing that could happen. When you are going over a large rock or boulder you need to have great control especially once you hit the top of the rock. The brake is needed as to not lurk over the rock while until you break past the top most portion of the rock you still need gas. Once over the break point you also need the slow crawl and control while the rear tire may still need the push over the rock and the front is coming down. Automatics just makes this a easier process. Their is a reason more serious rock crawlers use autos over manual transmissions. But saying that, if you like a manual then get one but the auto is a better crawler but not by a whole lot when you factor in experience.

i82much 06-12-2012 07:31 PM

21 Attachment(s)
It's a bit more complicated than just crawl ratios:

Torque converter - Wikipedia, the free encyclopedia

kcraw 06-12-2012 07:36 PM

Quote:

Originally Posted by rics1997 (Post 2466141)
Even though many have mastered the manual transmission, the fact is doing rock crawling need percise control with one foot on the gas and the other on the brake. With the JK at least you have anti-stall but it is still a lot easier with an automatic not to mention the forward momentum of the anti-stall can't over come an initial vertical climb. Also the torque converter adds the needed torque in certain situations. Of course even if you stall, in most cases it's not the worse thing that could happen. When you are going over a large rock or boulder you need to have great control especially once you hit the top of the rock. The brake is needed as to not lurk over the rock while until you break past the top most portion of the rock you still need gas. Once over the break point you also need the slow crawl and control while the rear tire may still need the push over the rock and the front is coming down. Automatics just makes this a easier process. Their is a reason more serious rock crawlers use autos over manual transmissions. But saying that, if you like a manual then get one but the auto is a better crawler but not by a whole lot when you factor in experience.

Good point. I don't do a lot of rock crawling but some, and it is a little tricky with the JK trying modulate 3 pedals at once. I've also got an 07, so none of that HSA thing going on with my manual. In your experience, does the reduction in pedals outweigh slower crawl of the manual?

Also, anybody hear about anything like the Rubicrawler for the new engine/transmission?

kcraw 06-12-2012 07:39 PM

Quote:

Originally Posted by i82much (Post 2466279)
It's a bit more complicated than just crawl ratios:

Torque converter - Wikipedia, the free encyclopedia

Yeah, I was wondering how that came into play. I'll read your link, but any quick summary for how the torque converter changes the equation, so to speak?

Adding: Or any information on the torque converter in the new JK?


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