BamaBleach's FJ40 buildup

[BamaBleach]

It was now time to start working on the Toybox itself. Marlin sales a complete kit that includes the output shaft, 2 piece front adapter plate, low range mini-truck t-case section, and rear adapter kit all together and ready to go. The same setup that is described in the toybox build that I linked earlier in this thread.

I decided to build my on kit because I could do it cheaper. It added a lot of extra work and added a lot of trouble for me because there isn't a lot of info on this out on the web.

The first thing I did was modify my reverse light switch. I detailed that part of the project in another thread because it's pretty detailed and I figured others might find it useful.

Here it is:
https://forum.ih8mud.com/40-55-series-tech/311796-modified-reverse-light-switch-toybox-users.html

And here's a pic of the 2-piece front adapter that goes between the h42 and the toybox:

 

[BamaBleach]

If you plan to build your on toybox you'll need to find you a top-shift mini-truck transfer case (you can use a forward shift with modifications).

Here's the one I used:

Here's the empty case all cleaned up and ready to be modified:

 

[BamaBleach]

One of the problems I ran into on this build had to do with the toybox housing (the mini-truck reduction box) and the bearing that is supplied by Marlin.

The new input gear that came with my front adapter setup had a #6209 bearing that measures 3.345" OD. The bearing that came from the donor mini-truck case had a #5307N bearing that measures 3.148" OD. So the new bearing is too large for the reduction box and the old bearing doesn't have a large enough ID to fit the new shaft.


But here is what I didn't know at first but found out after I got off the phone with MC:

When you just purchase the adapter kit you also have the option to pay a $100 core charge for a modified reduction box housing. When you send your housing back to Marlin they reimburse the $100. The modified box is simply bored out to accept the larger bearing.

That option was looked over when I ordered my kit. No big deal because my dad runs a machine shop so I would have deferred anyways.

Here's a picture of the difference:

 

[BamaBleach]

Here's a pic of the new gear/bearing that goes in the toybox that has the right spline count for the new output shaft:

Here you can faintly see the bearing # (sorry a bad pic):

Here's the guts to the toybox:

And here it is all put together and ready to go:

 

[BamaBleach]

Now it's time to freshen up my Cruiser t-case. I did a few mods to it to hopefully make it a better, strong case.

The first thing I did was clean it up!

Dirty:

Clean:

I also had the speedo housing machined out to accept two seals (search the 40 section for "mudrak" if you don't know what this is):

 

[BamaBleach]

The next thing I did was got in touch with Georg @ Valley Hybrids (orangeFJ45). He makes a couple of simple parts that really add to the strength of the stock t-case. Shoot him a PM for pricing. One of the best upgrades you can make to your t-case!

T-case saver (comes with new hardware):

Nose cone saver:

And I upgraded to 10mm studs on the nose cone:

 

[BamaBleach]

Since I upgraded the hardware on my nose cone that meant some minor machine work needed to be done. That wasn't a big deal for me because I already had the case completely disassembled.

It was a really easy process.

measure the bolt hole on the ring:

OD of the stud:

Dad did it in two steps so it didn't take out too big of a chunk at once:

1st step:

2nd step:

 

[BamaBleach]

Now the case itself had to be modified to accept the bigger studs:

And it needs to be threaded...

So he first made a thread block:

 

[BamaBleach]

And the finishing touches:

 

[BamaBleach]

And here's some pics of the double seal on the speedo housing:

And also the T-case saver:

 

[BamaBleach]

A few more random pics...

Old Clutch:

New Clutch:

Old pressure plate:

New pressure plate:

 

[ullose272]

is that spring over with stock springs? does the 37s fit good

 

[EWheeler]

Great write up. Thanks for taking the time to do it.

First question:

Why did you keep the 4 speed case? Why didn't you get the adapters for the splitcase and find a splitcase to use?


Second question:

I read through your thread twice but still didn't quite follow what you did as far as sourcing your own parts. What exact parts did you purchase from marlin and what did they cost? What exact parts did you source yourself?

If I understand correctly, you just bought the new tranny output shaft & the adapters and bought a minitruck case to use as the "doubler". What gears are in the minitruck case? What was the total cost all said and done?

 

[BamaBleach]

is that spring over with stock springs? does the 37s fit good

Yes and yes. I had to slightly trim my rear fenders in the rear. If you look closely you should be able to see it.

Once the new drivetrain goes in I'm going to use 60 or 62 springs in the rear to stretch my wheel-base out for the added length of the toybox. I'm actually going to cut my fenders more and do some trial and error on different spring configurations to get lower overall.

 

[BamaBleach]

Great write up. Thanks for taking the time to do it.

First question:

Why did you keep the 4 speed case? Why didn't you get the adapters for the splitcase and find a splitcase to use?


Second question:

I read through your thread twice but still didn't quite follow what you did as far as sourcing your own parts. What exact parts did you purchase from marlin and what did they cost? What exact parts did you source yourself?

If I understand correctly, you just bought the new tranny output shaft & the adapters and bought a minitruck case to use as the "doubler". What gears are in the minitruck case? What was the total cost all said and done?

Thanks!

1. This answer will also help answer the second part. At the time I was sourcing parts, Marlin did not have the split-case kits available. They also didn't have all the parts they needed to make a toybox for the 3-speed and 4-speed cases.

But your thinking is right, it's stronger and an overall upgrade over my 4 speed case. I did the best I could by doing some mods to it.

2. At the time of my parts sourcing, Marlin had the front adapter kit but didn't have all the parts needed to make a complete toybox. I lucked out because a member (LukeZero) here on the forum was selling essentially the rear adapter kit that goes between the reduction housing and the 4-speed case.

So here's the breakdown:
A. Front Adapter kit from Marlin - approx. $550 (call and they can give you a solid price). That comes with a 2 piece adapter. One part bolts to the back of the H42 tranny. The other piece bolts to the reduction housing of your donor mini-truck case. It also comes with a new output shaft for your tranny. And it also comes with a new bearing for the reduction housing. For a $100 core charge you get the modified reduction housing that fits the new bearing (this is the part I describe earlier that the salesmen forgot to offer to me). And it also comes with a marlin shifter knob.

B. Top-shift mini-truck t-case. You'll take it apart and use the low-range reduction section of the case that includes the shifter. The gears in this case are 2.28:1. But you can buy 4.7:1 gears from Marlin. I got it from my dad. I think he paid about $50 for it. He got it with some axles and other yota junk.

C. Rear adapter from forum member. He was asking $250 for the parts or $300 for the parts and the 4-speed case that was behind it. I paid the $300 so I would have a spare case. It came with the rear marlin adapter plate, a bearing with a machined Al spacer, another two-piece spacer welded together, a transfer case gear with correct spline count, and a new shaft that goes from the reduction housing to the 4 speed case (I think this is the part that Marlin is having a hard time sourcing). Marlin's kit comes with new, longer hardware. I had to buy my own.

$550 (front kit) + $50 (mini case) + $250 (rear kit from forum member) + $20 (new hardware for the rear) + $50 (gaskets & oil) = $920 approximately

So with some shipping I'd say $1000 is about right. When Marlin was selling their complete Toybox I think it was around $1800.

 

[ullose272]

did you do the spring reversal?

 

[lulo]

Perfect assembly of the gearbox

 

[BamaBleach]

did you do the spring reversal?

I have a shackle reversal up front. The military wrap is currently at the back and that needs to be fixed.

 

[ullose272]

you didnt reverse the springs tho for a longer wheelbase?

 

[BamaBleach]

you didnt reverse the springs tho for a longer wheelbase?

not yet but I will once the new drivetrain goes in.