Random gearbox question.

I'd like to know if there's a rated input torque for the r7me manual gearbox, or how much torque has anyone put in one before it went bang.  In essence how strong are they? 

There is certainly one torque limit.

My other car has an 8 speed ZF auto gearbox because it is too torquey for the dual clutch units. This other manufacturer has it open for everyone to see.

How to know that limit on the Suzuki gearbox might be a case for some old established Dealer to find out, it mustn't be that hard.

On another Japanese I could easily find out, but not on Suzuki, unfortunately.

Anyone to the rescue?

I can't give a figure but I can tell you about my experience.
I replaced mine recently as it had developed an intermittent metallic squeak in 5th gear under load. This is after 120,000 total miles, 40,000 of which have been in my ownership regularly towing 1,200kg and 30,000 of those miles have been with a Liana 1.6.
I have yet to strip it to see what the exact failure is but I suspect the high load I'm putting on it in an overdrive gear is definitely a factor.
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more or less same experience here but I have the R72 new version 2010-ish.
The R7me have other ratios so should be able to take more. With higher ratios the pressure on the bearings from the gear mesh will increase and likewise reduce if the ratio outside the gearbox is changed to move more of the torque transmission to the transfer or diffs.

Nowadays while I am waiting for time to put the low geared transfer case back in the car, my clutch is smelly with the original transfwer gears. Wich it was not with the low gear kit.

the R7me has more or less the same gears as the SJ box and that could take a lot of beating.

as a rule of thumb if you double the forces on the bearings you will reduce bearing life to 10-15% of what it was before. But as there are gears also in the transfer and diffs in not an easy calculation.

I think it can take a lot but it will reduce the total service life. but by how much?

Also if you increase the rpm it will reduce torque and strain on the bearings and shafts. But only up to a point where high rpm will reduce bearing life again.
and having no load on a spinning bearing will also reduce life so it is not as easy as 2+2.

Finally doing that Rover V8 swop, eh @Lambert?  

I used to do engine swops in vintage sports cars.  No replacement for displacement, was the motto.  What I saw then was that

1. no car manufacturer will give you a rating of any kind for their gearboxes, only aftermarket gearbox companies explicitly selling to hotrodders will do this; and
2. the boxes don't generally go bang, but as @yakuza says, there is a strong relationship between wear and power applied.  Generally, since you are putting maximum torque through in the lowest gears, the bearings on those will go first.  You get increasing noise (growl) well before you get any kind of misbehavior such as popping out of gear.

The only time I can think of where I completely grenaded a gearbox turned out to be due to improperly hardened aftermarket gears.  In my opinion, the tiny clutch in the Jimny means you are not likely to overpower any gearbox you put behind it.

Honda k20 possibly. But initially more likely an m13 on itb running rwd only on low profile 205s to correct the gearing. Thinking the r7me being stronger will be happier for longer. Earlier jimny are also mildly less expensive.