Improve My Perspective on Automatic Transmissions

SSTJ

SSTJ

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Hi all,

I’ve always rolled my eyes at auto-trans TJs, thinking they were built to appeal to those who couldn’t or wouldn’t learn to drive stick.

I learned recently that two Jeepers with MUCH more off-road experience than I have both drive automatic transmissions. So I figure I have something to learn.

What’s the main appeal? Are there benefits when off-road?
 
I bought my TJ 22 years ago with a 5-speed manual transmission thinking it was going to be the way to go. The 5-speed was fun on the street and on some trails but once I got hooked on rock crawling and finally did a REALLY REALLY tough trail called Sledgehammer in Johnson Valley, that's when it hit me that my 5-speed was not the best tool for the job. Not to mention I was the only guy in the group running a 5-speed. It was really a tough day, most were making gentle comments like 'so when are you going to convert your 5-speed to an automatic?' after having seen such a tough trail.

It was a couple months later that I did the conversion in my garage, it took about 3 non-continuous days.

Why? The torque converter in front of an automatic is basically some serious magic. The three key things it does are 1) gives what is in effect an infinitely low 1st gear ratio. Lower in effect than any(!) manual transmission. You can go .00000001 mph (or stop completely without killing the engine) in 1st gear if you want without stalling the engine... that kind of a low of a ratio. Then 2) the torque converter does "torque multiplication" which means it gives 2-3X more low-end torque than you get with a manual transmission. That's a nice thing to have when you're trying to get up & over a big obstacle. 3) An automatic gives an AMAZINGLY increased amount of control on super-difficult sections of trail, especially if you're also climbing. Go up a climb at a snail's pace in 4Lo and Low (1st gear)... stop by just taking a little pressure off the gas pedal, roll back a bit for a different line by just removing a little more gas, then start forward again with more gas pedal. Like dancing up & down an extra-tough section of trail to find that line that works.

Most serious rock crawlers converted to automatics years ago. It's the best modification I've done, seriously. My 5.38 gears are great, so is the 4:1 transfer case, so are the front & rear lockers. But what really makes my TJ work well on tough trails is my automatic transmission. It proved to be a better upgrade than I could have imagined while I was doing it.

P.S. I broke my front axle shaft that day... these are from that run in 2003 that convinced me to convert to an automatic.

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Blaine is currently converting my manual TJ to an automatic. Do you think I am having him do that because I can’t drive a manual? @starkey480 recently converted his manual to an auto. @Eddie Greenlee is also currently converting his manual to an auto.

Why do you think this is? Surely it can’t be because we’re all stupid 😉

A manual and auto built the same can go all the same places. The only difference is that in the manual you’re going to be challenging yourself maybe three times as much on the same obstacle.

If you like a challenge, by all means, keep your manual. I however would rather focus on other things.
 
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Auto transmissions weren’t as good as they have become and some have surpassed manuals in reliability and all the things @Jerry Bransford mentioned in his post.

Autos have become the go-to for hard core wheeling, just as 33” tires used to be big and now they come on factory rigs.
 
Kid Mechanic said:
Auto transmissions weren’t as good as they have become and some have surpassed manuals in reliability and all the things @Jerry Bransford mentioned in his post.

Autos have become the go-to for hard core wheeling, just as 33” tires used to be big and now they come on factory rigs.
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According to my dad who was active in the 70s-mid 90s, he would often see automatics drain fluid out of the torque converter during a steep climb. When we starting talking about what is happening today, he was surprised at first that autos have become the preferred transmission for racing and difficult rock crawling.
 
I love the automatic in my TJ. I will add that the 32rh is a torqueflite internally. A design from the early 1960s. And the 42rle is the 41te internally which launched in 1988, in the dodge caravan.
 
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Autos definitely have their place - and in absence of correct gearing, they're a hell of a LOT cheaper. The compound gearing needed to beat an auto is expensive and cumbersome (see @Jerry Bransford 's comments) - especially in light of modern engines that develop their most power at relatively high RPMs.

Its the same story over in the RV world - everybody switched to autos decades ago - including me...

... until I got so damn bored driving the thing that I switched back to manual and added an underdrive unit. Which still didn't give me low enough gearing for some situations, but it was "adequate" and a hell of a lot more fun to drive. Still, I almost got myself into trouble once - started up a very steep hill at a run in 2nd, trailer in tow. Halfway up, I knew I was going to have to grab first, so I did. As expected, the rear end broke loose and I had the dreaded wheel hop. I did the only thing I could, I backed out of the throttle and hoped! The hop stopped and the day was saved. If it hadn't, I would have been stuck on a very steep hill with no way to get re-started again - I didn't have the gearing for that. An automatic would have been able to restart, and also probably wouldn't have gotten into that situation in the first place.

I'd rather have a manual and the correct gearing - more fun to drive by far, more reliable long term, etc, etc - BUT - the "correct" gearing hasn't been made in over a half century for pickups, and is very expensive and not all that easy to find for Jeeps!

For "general use", I definitely want a manual, because mild gearing is good enough and the manual is cheaper - but that flips when you need power at very low speeds. I would love to see what a GMC big block V6, SM420, a very deep Atlas, and 5.14 or deeper gearing would do for a Jeep. Said engine is very heavy though - but it develops its power in the low end where it belongs.
 
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Jerry Bransford said:
I bought my TJ 22 years ago with a 5-speed manual transmission thinking it was going to be the way to go. The 5-speed was fun on the street and on some trails but once I got hooked on rock crawling and finally did a REALLY REALLY tough trail called Sledgehammer in Johnson Valley, that's when it hit me that my 5-speed was not the best tool for the job. Not to mention I was the only guy in the group running a 5-speed. It was really a tough day, most were making gentle comments like 'so when are you going to convert your 5-speed to an automatic?' after having seen such a tough trail.

It was a couple months later that I did the conversion in my garage, it took about 3 non-continuous days.

Why? The torque converter in front of an automatic is basically some serious magic. The three key things it does are 1) gives what is in effect an infinitely low 1st gear ratio. Lower in effect than any(!) manual transmission. You can go .00000001 mph (or stop completely without killing the engine) in 1st gear if you want without stalling the engine... that kind of a low of a ratio. Then 2) the torque converter does "torque multiplication" which means it gives 2-3X more low-end torque than you get with a manual transmission. That's a nice thing to have when you're trying to get up & over a big obstacle. 3) An automatic gives an AMAZINGLY increased amount of control on super-difficult sections of trail, especially if you're also climbing. Go up a climb at a snail's pace in 4Lo and Low (1st gear)... stop by just taking a little pressure off the gas pedal, roll back a bit for a different line by just removing a little more gas, then start forward again with more gas pedal. Like dancing up & down an extra-tough section of trail to find that line that works.

Most serious rock crawlers converted to automatics years ago. It's the best modification I've done, seriously. My 5.38 gears are great, so is the 4:1 transfer case, so are the front & rear lockers. But what really makes my TJ work well on tough trails is my automatic transmission. It proved to be a better upgrade than I could have imagined while I was doing it.

P.S. I broke my front axle shaft that day... these are from that run in 2003 that convinced me to convert to an automatic.

View attachment 231507View attachment 231508View attachment 231509View attachment 231510
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Hi Jerry-do points1,2and 3 apply to 42RLE too? Nice write up btw.
 
SSTJ said:
What’s the main appeal? Are there benefits when off-road?
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The automatic can be beneficial in situations where you have to back down, near a ledge, to make a 3 point turn or change your line. With a manual you would need to be really good at double pedaling or have a hand throttle.
 
I love the automatic, i freaking hate the 42RLE shifting. I am hoping an praying the W5A580 swap becomes a reality and paddle shifters can make road driving enjoyable again.
 
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In my case I looked at manuals but with a bum left knee it was too painful for city driving. Too much clutch work but the manuals were fun to drive. Ended up with an automatic.
 
Darsmith said:
In my case I looked at manuals but with a bum left knee it was too painful for city driving. Too much clutch work but the manuals were fun to drive. Ended up with an automatic.
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That was what happened to my father many years ago. Loved his manuals, but both knees were sub-par as he got older - switched to an auto for towing, but kept his manual for his commute until he retired.
 
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Automatics defiantly have a place in wheelin! They make driving offroad
way easier. ( unless you go down steep grades , forwards or backwards :eek:).
However, I personally prefer extremely deep reduction manual gearing.
( think Unimog). You decide what ratio is appropriate for the situation at hand.

Of course this type of goodness doesn't come cheap.
So the juice transmission is the easiest way out.
 
ColoJeep said:
Automatics defiantly have a place in wheelin! They make driving offroad
way easier. ( unless you go down steep grades , forwards or backwards :eek:).
Click to expand...
Methinks you have not driven an automatic with deep gearing on an extremely steep downhill grade. In 4Low and locked in Low, when on a scary steep downhill grade, my automatic with 5.38 gearing, 4:1 tcase and 35" tires will will have people behind me riding their brakes to keep from running into me.
 
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