RockLobster conversion

[Skovelev]

Hey I have an old 410 and I am thinking of building a new transfercase just like the one in the DIY section. But will i get the same low ratio on my 410 as he does on a 413?
I have both transfercases in the shed so im an on my way to getting startet. But will it give me any differens on my 410?

Sorry for my spelling i am from denmark so english is not my first...

Thanks for a great forum with a lot of inspiration

[dunk]

Yes putting a rocklobster t box in your 410 will make your gearing lower. It's the best mod you can do to any sj.

[twiss]

Unless you want to go fast

[ScottieJ]

Unless you want to go fast

but his High ratio will be the same as a stock 410 Tcase he already has Twiss

to :S:cuk, glad you find the site useful! here are the Tbox ratios for sjs

Tbox ratios

410 Tbox
Hi 1.58
Lo 2.51

413& Samurai Tbox
Hi 1.41
Lo 2.27

Rocklobster
Hi 1.58
Lo 4.16

With a 410 tbox both high and low ratios are already lower than your friends 413, once you have built a rocklobster your high will be the same as it was before and your low ratio will be roughly 80%lower.


Just to check your 410 tbox is a later style one with the 4wd light and the fatter props isn't it? the older 420 tboxes with no 4wd light and skinny probs cannot be used for a rocklobster as far as i'm aware.

[twiss]

but that's not any SJ is it

that's a 410... all 413s and Samurais will have slightly lower top end with a rocklobster

I personally can't be arsed with gearing changes. Bigger tyres want a bigger engine really

[dunk]

In fact if I had know what I know now I would have had a twin t-box from the start over a rock lobster but I would have changed alot of mods I have done to my sj but hey I love what I have ended up with. Lower gearing rules

[twiss]

Lower gearing is great, but now I can cruise happily at 70mph I don't want to give that up!

I hated driving at 55mph everywhere on the standard 195 tyres!!!
It used to take me about 3 hours to get to bournemouth, now it takes just under 2 hours.

If I got 31"+ tyres I would look at changing the gearing, or if I still had the 1.3 engine

[ScottieJ]

for your reference you can't use this style 410 tbox for a rocklobster

1981-1983??





I'm not sure what year this one is from and I'm not sure if the gears are the same as the ones with the 4wd switch? I dont think they are but could be wrong?



this is the one you need to buid a rocklobster
1984 onwards with 4wd switch. (and looks the same as a 413/samurai tbox)

[Skovelev]

Thank you for all your help. I do have det transfer with the switch.... Now i have to buy me a 413 transfer box... and some gaskets and bearings.... i am lokking forward to try it out ind the mud.....

You do not need top speed in the mud... Going 100 kmh in rough terrain is not an option in an sj.

And if i use the 410 transfer box i will stil have the same top speed on 4h but about 80% lover on 4low?

[ScottieJ]

Thank you for all your help. I do have det transfer with the switch.... Now i have to buy me a 413 transfer box... and some gaskets and bearings.... i am lokking forward to try it out ind the mud.....

You do not need top speed in the mud... Going 100 kmh in rough terrain is not an option in an sj.

And if i use the 410 transfer box i will stil have the same top speed on 4h but about 80% lover on 4low?

No worries, and yes the high ratio with the rocklobster will be the same as a standard 410 transfer box.

How are you going to machine the gears? there are a few ways of doing them

Rockwatt on here does them in the strongest method

A combo of nigel head and Rich's words '1 thou under sweat fit, turn a regester to keep it true to 0.001", Drill on the shear line (don't try using 'ordinary' HSS drill bits - they won't look at it!) and pin using four 3mm diameter silver steel pins, tig weld with high chrome content rods partly submerged in water to stop heat getting to the teeth'

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or there is always the older castleing method