Topic: need duals!!!

[toyotasarebetter]

i have a forward shift t case and want to know if i can use it with duals or if i have to scrap it and find two top shift t cases....

[abnormaltoy]

Only the rear case needs to be top shift, but any forward shift box can be converted. The kit is right at the bottom of the page.
http://www.marlincrawler.com/htm/transfercase/tcase_ac.htm#topshift

[79coyotefrg]

what tranny do you have??  if it needs a forward shift then  you NEED the forward shift box for your crawler

[toyotasarebetter [OP]]

So I can run duals through the forward shift case and not need the other t case? And how often do 21 spline break???

[BigMike]

The only thing you need to know is that the Rear Transfercase MUST be a top shift style, since it will bolt behind our adapter plate.

If this forward shift t/case of which you speak of is your donor case, then yes, it must be converted to a top shift style, no exception.

These gear drive transfercases last a VERY long time if properly cared for. So it really does not matter if you choose to turn your current transfercase into the Crawl Box or your donor transfercase into the Crawl Box.
But since your current transfercase is already mated to your transmission, I would just recommend converting that into your Crawl Box, and then using your donor case as your (2nd) transfercase (which will receive the drivelines).

Generally speaking, 21-spline setups are not recommend for drivetrains that are behind an engine of apprx. 170 ft-lbs of torque or more, such as Turbo R-engines, 3VZ-FE (3.0 V6), 3RZ-FE (2.7 4cyl), or better.

We have seen 21-spline setups fail behind stock 22R powered trail rigs, but this is very rare and certainly done with extreme prejudice towards heat treated metal components. In other words, you would have to drive extremely hard and very rough on your rig in order to break a 21-spline drive train with only 120-ish ft-lbs of torque.

I see more 21-spline couplers stripping out then I see 21-spline inputs failing.

However, if you plan on installing our 4.70:1 gear set in the back case, with it's Total-Spline™ input design, we have NEVER had a single 21-spline 4.70:1 input gear fail, nor have we seen a 21-spline coupler with a Total-Spline™ input gear strip out! It is a far superior gear that is a very strong 21-spline candidate and has solved the issue with stripped out 21-spline couplers.

Regards,
BigMike

[toyotasarebetter [OP]]

Sweet deal... How much would it run to get a donor case from you guys with twin sticks set up and mated to an adapter already???

[79coyotefrg]

Sweet deal... How much would it run to get a donor case from you guys with twin sticks set up and mated to an adapter already???

if going that route  i would recomend  just getting the entire dual case setup from them, then send both cases to them for cores

[abnormaltoy]

if going that route  i would recomend  just getting the entire dual case setup from them, then send both cases to them for cores

I did it with out a donor and ended up spending about as much on dealer parts as I would've just buying the donor. If I had it to do over again, I'd just buy the whole shebang from Marlin...it was fun though.
Mark

[toyotasarebetter [OP]]

thinkin i will just buy the whole shebang... i am the kid who got the complete thirds in paso... i thing justin is his name delivered them to me in his wifes car... she came too and pregnant... look at the dedication of marlins crew!!!!!!!!!

[Bloomcounty]

I see more 21-spline couplers stripping out then I see 21-spline inputs failing ?? how often does this happen ??

[79coyotefrg]

maybe with 37's  and REALLY big rocks,  and i bet thats in the rear case

i'd  HOLE LOTS rather strip a coupler  than a input gear