[garryc]

Got an 05 jimny.
Just put a a sierra transfer case with rock hopper gears into it.(Not personally had a trusted mechanic do the job)
Looking for someone in NSW to help sort it out.
Any suggestions?
Geared way to low in Hi its like riding a 2 stroke bike despite assurances from supplier of transfer case that it would provide only a 10% reduction in hi.
In 4wd wants to jump out of gear and is way too noisy.
No idea where to start looking
thanks

[Gwagensteve]

The super low high range gearing is normal. It's far more than 10% reduction in high.

Otherwise sounds like a poor gear install, although it's fair to say Sierra reduction transfer gears are much noisier than a chain jimny transfer.

[jdk81]

Assuming 4.16 gears?

Auto or manual?
High range reductions.
Auto is 1.58/1.32 ~=19% reduction
Manual is 58% reduction.

Who was the supplier?

[garryc]

VVT manual
Piranha who provided the 2nd hand transfer box bearing kit rock hopper gear set etc assembled it and freighted it to NSW
4.16 gear set.
I was assured that it would be a 10% reduction in hi
I haven't contacted them as yet

[tanshi]

sorry mate but you have been mislead.

manual vvt jimnys are 1:1 hi range I believe.

4.1 transfer are 1.58:1

[tanshi]

not sure of your tyre size but on stocker tyres you would be doing 5300rpm at 100 kmh

[tanshi]

even if you had an auto or an earlier model jimny non vvt it would still be 19% lower

[garryc]

OK guys after a long break with jimny sitting in the back yard, ready to try to sort it out.
Any suggestions of how to increase the gearing ie alternative diffs etc

thanks

[sideways]

As long as they knew it was a Jimny, Piranha goofed. Not only does this provide far to low gearing for your model (58% reduction), it provides much more than 10% for every model of Jimny. They should be responsible for sorting this out.

So being a VVT manual you've got 4.3 diffs and the 1:1 5th gear. On stock tyres you're doing 3755rpm at 110. Now you're at 5933rpm@110.

You can swap to a pre vvt gearbox (0.865 5th gear) and earlier model/VVT auto diff gears (4.1) and that will get you 4876 @ 110 on stock tyres, 4274 on 30" tyres.

If you really want to go hunting unicorns then you could pick up some diesel Jimny diff gears from Europe, these are 3.416.

3.416, stock gearbox and tyres. 4,713
3.416, stock gearbox and 30" tyres. 4132
3.416, pre vvt gearbox and stock tyres. 4072
3.416, pre vvt gearbox and 30" tyres. 3570

I'd ask Piranha for a refund, it's hard/expensive to make sierra transfer gears work in a VVT manual Jimny unless you're running very large tyres. Reduction gears for the Jimny transfer aren't cheap but they're a better solution for mild Jimny builds.

It'd help to know your tyre size and use of the vehicle.