Jimny manual versus auto: a deep dive

A common question asked in various Jimny fora is “should I get a manual or an automatic Jimny”. People then weigh in with their specific opinions, which is fine, but this also raises a bunch of misunderstandings like

“It’s a 4 speed auto, surely that means it revs more on the highway than the 5 speed manual?”

“Autos are better in the city”

“Manuals are better offroad” / “NO THEY AREN’T IT’S EASIER TO ROCK CRAWL AN AUTO”

“Autos in sand suck because they change gears when you don’t want them to” / “NO MANUALS SUCK IN SAND BECAUSE YOU CAN’T CHANGE GEARS WITHOUT LOSING MOMENTUM”

and variants thereof. I thought I could best address these and add to the conversation by a deep dive into the specifications of each transmission type, a bit on how they work and some of the potential positives and negatives that arise for each.

Sections

Quick comparison

Manual pros / auto cons

  • Manuals are cheaper / autos are more expensive
  • Manuals have better fuel economy / autos worse fuel economy
  • Manuals can be bought in the lower spec cars / autos reserved for the higher spec only
  • Manuals are lighter / autos are heavier (by 15 kg)
  • Manuals are less complex / autos have more complex things to go wrong
  • Manuals are easier to fool to get around electronics / autos have more ways of knowing what’s happening so you can’t fool them
  • Manuals will be faster to drive/accelerate / autos are slower
  • Manuals give you options if you have a flat battery offroad / autos cannot be roll started
  • Manual gearboxes probably last longer / autos probably less long
  • Manuals are easier to service, and also to modify for robustness offroad
  • Simpler reduction gearing – if you want stock gearing on 235/75-15 tyres, just put in the auto diff ratio instead
  • Super long term: lower purchase #s manuals might mean they end up worth more from scarcity (as of 2023 it’s roughly 25% manual 75% automatic for JB74 sales in Australia)

Auto pros / manual cons

  • (Near to medium term) Residual values of autos are higher due to more demand, less supply / Manuals will have lower immediate residual values
  • Autos are easier to drive in traffic
  • Autos are easier to drive offroad, especially in rocky segments or in long sand climbs
  • Auto gearing is slightly longer on the highway for *marginally* lower revs
  • Autos don’t have a clutch to change, which isn’t cheap if you don’t do it yourself
  • Autos are more likely to survive certain types of offroad abuse e.g. getting bogged and significant intervention of traction control or brake LSD / manuals will destroy their clutches if you end up in situations with lots of revs, little traction, lots of electronic aids intervening and limited driver sympathy
  • Autos have less stuff in the footwell, giving drivers somewhere to rest their foot even standard

Some conclusions that are backed up by what I discuss elsewhere

If you specifically disagree with some of what I say here – either in the tables above or in this conclusions bit – then I suggest it might be worthwhile absorbing in the detail of what I outline below. I just thought I’d put the conclusions up front for those who want to have their own biases confirmed quickly or those who wish to be outraged without the time taken to absorb the detail behind these conclusions.

The main conclusion is pick the one you think you’ll need or want. Most of your preconceived notions as to why you’d pick one over the other likely doesn’t apply. You cannot split them on things like revs on the highway, or even fuel economy much. While there is a weight penalty, it’s not huge. On the road they drive similarly even if the manual will feel perkier, accelerate significantly quicker and be a little more responsive and connected. The manual clutch is also quite light so it is not a significant burden in traffic compared to even many modern hatchback clutches, and a light car with a revvy engine is great in traffic, just sit in first and crawl along and accelerate when you need to.

While automatics are easier offroad, that doesn’t always imply better. Automatics are much easier in rocky terrain where you can ease in and out of drive simply and with a lot more options. A manual is either slipping the clutch, or you’re stopped or you’re fully engaged. In sand, if you need to change gears a manual is more challenge and will lose momentum. Locked into a particular gear the automatic will stay in that gear or go to lower ones if needed.

Any descent is going to be easier in a manual in first gear low range, with or without hill descent assistance from the car. An automatic is more likely to heat up its brakes doing that. An automatic is also prone to overheating the transmission fluid in long sand runs or large climbs, especially if you are in high range and relying on the torque multiplication of the torque converter. While not common and there are fixes, this can be a thing.

Automatics also have a harder time to do things like extend the gearbox breather so are more likely to ingest water, are then harder to clean out, and more things can go wrong when they do ingest water. On the flipside, a manual car with lots of brake LSD intervention basically is going to heavily wear the clutch and potentially destroy it very quickly. The slave cylinders for clutch actuation are also prone to wearing the seals due to mud/water ingress, too.

If you wish to tow, the automatic is easier for things like reversing trailers around or getting things moving. The automatic towing a reasonable load, however, really needs to have overdrive locked out and stick to the 1:1 gear ratio of 3rd gear to avoid damage through the overdriven top gear. This will have significant fuel economy penalties on the highway. The manual, however, can even sit in the direct drive 5th gear all day much more happily without fear of damaging things through sitting at a high load in an overdriven gear.

Gearing

Rather than repeat myself, the various things about the gearing for the Jimny lives over here.


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