So I've been hunting for a new 4runner with 4x4 and while searching and the help of some people on here I have found a couple that are manual transmission. I love driving manual on the street (which is 75% of what I'll be doing with the new runner) but I feel like an automatic would be a lot better/easier while offroad. For example, what if you are on a steep incline and do not have any space to roll back and need to move forward quickly?
Curious to see some opinions to offroading with a manual/automatic and why do you prefer either one?
The short answer:
If you are just going for all around offroading and daily driving I'd go with a manual, they are all around more fun. However, if rock crawling is important to you, then hands down, I'd go with an automatic transmission. You can't beat the control of an auto when rock crawling.
The long post:
Really, to get a good answer for your question you're going to have to figure out how important your rock crawling performance is to you. That 25% of the time when you are off road what kind of off roading is it going to be? Off roading means a lot of different things to different people. For some it's mudding, others it's desert racing, slickrock, sharp rocky terrain, snow bashing...
Here in Colorado the mountains are young and the trails are rocky. We have very little mud and have plenty of opportunity to rock crawl. Moab is only 5.5 hours from us. We have so many trails out there that even though we run a trail nearly every weekend we don't get the feeling of having to run the same trail again for a couple of years.
In the desert, mud, snow bashing, hill climbs, and on the pavement I definitely prefer a manual transmission. You get more control, you can dump more power to the wheels when you slip the clutch. You can fishtail, do donuts (Not on a trail!), and you can rock your rig out of a snow hole. You can be in 4 lo and while still moving drop it in to 4 high. Way more fun in a manual. Even with a stock supercharger on an auto 3.4 you still don't have enough power to be able to do those things near as well as with clutch control.
When it comes to rock crawling though I would only consider getting a manual if I knew I was going to put in dual cases. Even with a crazy low ratios you will still find yourself “pressing and praying” since you can't always stop mid way up a vertical face and adjust your wheels to a new line. The parking brake is helpful but unless you get a hydraulic hand brake for all four wheels the stock parking brake just isn't going to stop the vehicle from going back. And if anyone tries to argue that one my response is that you ain't on something steep ha! I used to heel toe and use the hand brake when wheeling but even though I've been driving clutch for the past 20 years and actually keep in practice with heel toe, I still rolled back, stalled, smoked my clutch, overshot and smacked my rig on the rock. A good wheeler no matter how good they are has to smoke his clutch some to get through a hard rock crawling obstacle. You need to because our stock clutches are not big enough to do otherwise.
With an auto and rock crawling you have a few advantages. First and foremost is controollllll. The regular crew at RM4x4 use both feet when rock crawling. Right foot squeezes in the power, the left foot controls speed and brakes. When I rock crawl up stuff with open diffs I start by looking at my lines which often zig zag. I might crawl up 14 inches, stop, turn hard to the driver's side, stop again, go 6 more inches to catch a 2” wide strip with my knobbies. In some ways it's more like rock climbing as it is rock crawling. Slow RPM allows for the tires to get as close as possible to the maximum amount of friction (Coefficient of Static Friction). In my manaul rig I had to pick a line and roll through it. That sometimes meant taking it faster then I was comfortable with and praying that I didn't bounce in a bad way.
Something else that having a manual does is that it allows you to power load the transmission. For example if you are going off a 7 foot, near sheer, drop there's a real possibility that you could endo and flop onto your roof. With an auto I've found it works best to get the RPMs in the 1000 – 1500 range and use the brake to control the movement. That way as all the tires break free and start to slide forward, you can let off the brake and the already rev'ed up engine can pull your front end forward preventing the flop. With a manual you can push in the clutch on descent but if there is a hole dug out at the bottom (as there often is from rigs trying to get up the obstacle) it might not be enough to keep the front end moving.
CV axles get broken most often because of the severe angles that are put on the joint at full turn. It's a lot easier to get full droop and full turn with an auto because you can stop mid obstacle and try a new line. That luxury does cause more broken axles though. So if you want to avoid that don't crank the wheel to the steering stops.
FWIW I sold my manual to get an auto because I got tired of seeing my wheeling buddies finesse their way through stuff as I bounced, smacked and stalled out. There are obstacles that I do now that I wouldn't want to try in a manual because if I were to stall going up a long and steep ascent I might not have enough vacuum left to stop the rig if I stall the engine. In Moab that could be fatal.