Fj40 Advance Adaptors Rockbox Aa Rock Box Doubler

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I want to expand my low gearing options for my '78 FJ40 (stock drivetrain). I've decided a doubler is really the way I want to go for my application. The AA Rock Box is a lot cheaper than the Marlin Crawler Toy Box. I don't want an Orion because you are either 4:1 or 1:1. I also want to retain the stock transfer case and tranny, so forget the SM420 and 465.

Unfortunately, I can't find an Rock Box since AA has recently discontinued them due to lack of demand. Who knew? I know everyone loves Marlin, but there's a big difference in the cost (almost double). The AA box was under a grand at Downey until AA recently ceased production. Marlin is nearly twice that much. I've searched the forums for a month and haven't found any substantiated evidence to discourage me from buying a Rock Box over the Toy Box.

That being said, doe anyone know where there is one? Maybe one left in stock at a vendor or someone getting rid of one.


Thanks!

LC
 
I want to expand my low gearing options for my '78 FJ40 (stock drivetrain). I've decided a doubler is really the way I want to go for my application. The AA Rock Box is a lot cheaper than the Marlin Crawler Toy Box. I don't want an Orion because you are either 4:1 or 1:1. I also want to retain the stock transfer case and tranny, so forget the SM420 and 465.

Unfortunately, I can't find an Rock Box since AA has recently discontinued them due to lack of demand. Who knew? I know everyone loves Marlin, but there's a big difference in the cost (almost double). The AA box was under a grand at Downey until AA recently ceased production. Marlin is nearly twice that much. I've searched the forums for a month and haven't found any substantiated evidence to discourage me from buying a Rock Box over the Toy Box.

That being said, doe anyone know where there is one? Maybe one left in stock at a vendor or someone getting rid of one.


Thanks!

LC
Hello my Mud- Brother,
It doesn't look like you have got a response yet....your post came up on my search for a doubler box.
So i thought I would direct you to "MAN-A-FRE" they still list a " AA Double box" I believe it listed at $1295. Also they have a wicked list of FJ40 parts !! Hope that helps.
Enjoy, Terry
 
Hi All:

If you are dead-set on a "doubler" but don't want to buy the MarlinCrawler Toybox then consider the NP203 GRB adapter kits available for your H42 tranny.

How this works is that you have the H42 tranny/ an adapter/ the gear reduction box from a NP203 t-case/ an adaptor/ the "four-speed" t-case. You will need to fab-up shift linkages, etc. for this combo.

Look here for more info:

(P/N 50-8801) Toyota Land Cruiser/NP203 Doubler (for 10 spline transfer cases)

Good luck!

Alan
 
that kit doesnt say anything about using an h42 tranny....
says you need a sm465 and three speed transfercase... under the technical documents...

unless i am missing something...
 
Hi All:

You probably need to call AA and chat with their Tech Guys to get the full scoop.

I have a friend who did this swap into his '78 VJ40 several years ago. His rig is running the H42 four-speed.

Regards,

Alan
 
anyone know if this adapter plate will work with the stock h42?? So what would this set the crawl ratio at?? And this won't work with the 79 transfer correct? only a pre 73 transfer?
 
Hi All:

"Badass," IIRC the AA online catalog lists two versions - one for the TLC "one-piece" t-case and anothre for the TLC "split" t-case.

My friend used the H42 and "split" t-case from a '82 FJ60 in his VJ40 with the NP203 GRB.

Regards,

Alan

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anyone know if this adapter plate will work with the stock h42?? So what would this set the crawl ratio at?? And this won't work with the 79 transfer correct? only a pre 73 transfer?
 
AA also shows a 16 spline as well as the 10 spline so your 16 spline 4spd t/case is covered.

I just got a 203 for $25 and plan to go my 420/old adapter/203/new adapter/3spd t/case after some more research.

good luck
 
AA also shows a 16 spline as well as the 10 spline so your 16 spline 4spd t/case is covered.

I just got a 203 for $25 and plan to go my 420/old adapter/203/new adapter/3spd t/case after some more research.

good luck




Should not have any problem breaking another Land Cruiser one-piece transfer case into two pieces.....



:lol:
 
Hi All:

Just like "Poser" mentioned, my friend went to the later "split" type t-case from a (IIRC) a '82 FJ60 because he had blown a one-piece t-case already.

The *only* reason to stick with the older one-piece t-case is if you are beholden to the t-case mounted parking brake. If so, then get your rig an Orion! :D

Regards,

Alan
 
WOW! Thanks for reopeniing this old thread!

I had decided to go with Marlin's ToyBox and was ready to pop for one, but I don't think they they are still avaliable. They show up on their new website with less detailed info than in the past. I emailed 3 times and called once and no positive response. I'm still willing to beilieve they are standup guys, but think they must just be into truck stuff these days based on my experience.

The AA RockBox is dead. They have the parts to support units in the field, but not the parts to build them any more. Too bad.

I bought an H41 today with a 3 spd case. Not the lowest gearing, but a step in the right direction. 50% lower gearing and I'm in the East, not big boulder stuff here.

That other doubler option is intriguing. I'll look into it for one of my other projects. For now, I'm settle on the H41/3SPD case.

Thanks for all the input!

LC
 

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