Marlin Crawler - Toybox / Doubler Questions

[Randy88FJ62]

Let’s say that Marlin Crawler will come out with the mystery box for the A440F FJ62 and FJ80 owners soon. This means lower crawler gears for our vehicles. What I don’t understand is how this mystery box between the transmission and the tcase works.

Here’s why I ask: I have 4.11 thirds with ARB’s and I am about to move up to 35’s. We all know that 35’s and 4.11’s don’t work well together. I would rather not regear to 4.88’s but it looks like it will be the case. I want better cruising RPM’s to get my rig to the trails. Keeping 4.11’s would be awesome for freeway speeds and using the toybox for crawling when I get there would be great.

People with doublers or toyboxes, how are your gears setup to run bigger tires and how do you balance freeway gearing with the offroad gearing?

Also, how do MC’s boxes work? Are they solenoid actuated or do they use manual sticks to shift?

 

[PPFJ60]

I have an NP203 doubler that is 1:1 in high range so no change to road gearing. It's 2:1 in low plus the LC split TC 2:1 gives me two choices for lower gears. With the 700R4 automatic and 4:88 gears I am running about 64:1 in double low.

To get lower gears all the way around you would need a doubler that was not 1:1 in high range.

 

[bustanutley]

A toybox is just the reduction half of a Toyota pickup t-case. They use a manual t-case shifter to shift them. It could be possible to make the air or actuator shifted but that would be on you to figure out, I have never seen it done.

 

[ntsqd]

A toybox is just the reduction half of a Toyota pickup t-case. They use a manual t-case shifter to shift them. It could be possible to make the air or actuator shifted but that would be on you to figure out, I have never seen it done.

I've been working on air shifting and a revised shifter arrangement, on and off, since I got my Marlin Crawler adapter in 1998. The assembly is still sitting on my garage floor, but at least it's together. I've been trying for a year to get the new shifter base machined. A shop that we use for work said they'd do it for free and after a year it still wasn't done. I've now got someone else lined up to do it, but it's looking like not until after the first of the year.
The project isn't that difficult to do, my interest varies. Stuff gets done when interest is high and doesn't when low.

 

[NocalFJ60]

I setup my cruiser with 4.11's, H55F, and toybox and the smallest 35's (closer to 34's) I could find and like the setup for what I like doing. I can cruise on the highway at 70 if it is relatively flat. I would think about re-gearing to 4.56 if I did a lot of mud and sand. The toybox gives me the lower gears on the trails so 4.56 or 4.11 don't make a difference on the trail just on the road.

The toybox is just gears and is manual actuated by a shifter in the floor. It is a simple bullet proof design.

 

[Randy88FJ62]

I setup my cruiser with 4.11's, H55F, and toybox and the smallest 35's (closer to 34's) I could find and like the setup for what I like doing. I can cruise on the highway at 70 if it is relatively flat. I would think about re-gearing to 4.56 if I did a lot of mud and sand. The toybox gives me the lower gears on the trails so 4.56 or 4.11 don't make a difference on the trail just on the road.

The toybox is just gears and is manual actuated by a shifter in the floor. It is a simple bullet proof design.

What is your cruising RPM at highway speeds with 4.11's and 35's?

Do you feel that the 3FE can handle 35's with 4.11 gears? Hills sometime become a problem for me now with 4.11's and 31" tires...

 

[GLTHFJ60]

What is your cruising RPM at highway speeds with 4.11's and 35's?

Do you feel that the 3FE can handle 35's with 4.11 gears? Hills sometime become a problem for me now with 4.11's and 31" tires...

If your 3FE can't handle 31"s on hills, then I doubt that it will fare any better with 35"s. There's gotta be a power issue there though, because my FJ60 can handle 33"s with the stock 3.73's perfectly up hills.

 

[Randy88FJ62]

My 3FE has 280,000 mi. Maybe it's worn out or maybe it needs a tune up. There is an exhaust leak on the drivers side from one of the hoses near the charcoal canister / silencer area. Not sure if that could cause any issues.

Does adjusting the valves increase power if they are out of whack?

 

[trd55]

What is your cruising RPM at highway speeds with 4.11's and 35's?

Do you feel that the 3FE can handle 35's with 4.11 gears? Hills sometime become a problem for me now with 4.11's and 31" tires...

What happens is the motor gets out of its torque band when in overdrive. Then your are left to run in 3rd gear all the time(kicking it down to 2nd for hill climbs, which inturn will burn up the transmission. The 3FE, from my experience likes to be at or above 2500 rpms to pull any load and cruise freely. That said, I am running 35s(MTRs) and stock gears. I also have a Rodney Extreme transmission. The two things that help are the torque converter lockup in 3rd gear and the fact that the modified valve body reduces the amount of power the factory transmission eats up. I also have tweaked the AFM and advanced my timing a little. That all adds up top a little more power to maintain speed in overdrive. I can cruise at 2000-2100 at 70+/- mph. Add a tail wind and it runs great. Add a headwind and I will be runnig in 3rd. Good luck.

 

[trd55]

If your 3FE can't handle 31"s on hills, then I doubt that it will fare any better with 35"s. There's gotta be a power issue there though, because my FJ60 can handle 33"s with the stock 3.73's perfectly up hills.

Your FJ60 also has a 2F. You have a bunch more torque at a much lower RPM. The 3FE will build torque starting at 2200 rpms to 3200. The 2F starts building torque around 1200Rpm. (most of this is from memory, so don't cruicify me with) Fact is, since the 2F has a longer stroke, it builds torque at lower RPMs. The 3FE was made to run at higher highway speeds, thus the shorter stroke and higher revving motor.

 

[Randy88FJ62]

$1,000+ for an extreme valve body seems a little... umm extreme for my price range. What effects would I get by just adjusting the timing? This is a subject I have not delved into at all.

 

[NocalFJ60]

What is your cruising RPM at highway speeds with 4.11's and 35's?

Do you feel that the 3FE can handle 35's with 4.11 gears? Hills sometime become a problem for me now with 4.11's and 31" tires...

About 2300 at 65 mph (gps).

It could handle it but driving my cruiser to Moab this year takes some patience on the hills. The 2f just lacks in horsepower and 3FE is a little better but not much if I remember correctly. You have an automatic so it does make some difference.

 

[RredFJ40]

Let’s say that Marlin Crawler will come out with the mystery box for the A440F FJ62 and FJ80 owners soon. This means lower crawler gears for our vehicles. What I don’t understand is how this mystery box between the transmission and the tcase works.

Here’s why I ask: I have 4.11 thirds with ARB’s and I am about to move up to 35’s. We all know that 35’s and 4.11’s don’t work well together. I would rather not regear to 4.88’s but it looks like it will be the case. I want better cruising RPM’s to get my rig to the trails. Keeping 4.11’s would be awesome for freeway speeds and using the toybox for crawling when I get there would be great.

People with doublers or toyboxes, how are your gears setup to run bigger tires and how do you balance freeway gearing with the offroad gearing?

Also, how do MC’s boxes work? Are they solenoid actuated or do they use manual sticks to shift?

This is my basic long term plan. I'm running 33's and 3.73's right now and like the highway RPMs. At 2500 I'm doing about 65. Off-road isn't so great, I'd love to be able to go a whole lot slower. I've got a set of 35's that I'll be swapping on soon and I'll try those with the 3.73's for a bit. If the 2F doesn't have the guts for the 35's I've got a pair of 4.10 diffs to swap in that will bring me back to the gearing that I've got now. I've also got an H41 sitting around that needs to be rebuilt before swapping it in. That will give me the granny first for off road and easier starts on road. For me it's all trial and error. Try something and then fix it if necessary. So the plan right now is h41 and 35's and adjust the diffs to suit the rubber overdrive.- I'd love to add a toybox if necessary for off-road.

 

[NocalFJ60]

I've got a set of 35's that I'll be swapping on soon and I'll try those with the 3.73's for a bit. If the 2F doesn't have the guts for the 35's I've got a pair of 4.10 diffs to swap in that will bring me back to the gearing that I've got now.

The 33's is hard enough for 3.7's. If you drive too much with 3.7's and 35's you can also plan on a new clutch unless it is new then you might have some to burn.

The H41 would definitely help but might still might not be enough to comfortable drive around and cruise up the hills on the road.

Looking forward to getting up to that neck of the woods and doing some runs with the Jefferson State crew.

Goodluck

 

[rusty_tlc]

My set up is 36" Swampers with 4.11 differential gears, ARB F&R, 2.5:1 Toybox and 4.0:1 Orion.
On the flats I can run all day long at 65+ without winding the 2F up too bad (no tach so I have no idea exactly what RPM's).

On moderate grades I can usually stay in fourth, I may be going pretty slow by the summit if it's a long grade.

On really long steep grades, like Kingsbury heading up to Tahoe, I do a dance between third and fourth.

Off road the stupid low gearing lets me apply power very gradually so there is less stress on the birfields and axles even running the heavy 36" Swampers.

I think that is what you were asking for. Hope it helps.

Edit: My FJ40 is probably a bit lighter than a 60 but not that much when you count the 8274 with 150' steel cable, HFS bumper, family roll cage etc.

 

[Cruiserdrew]

Big difference between the manual tranny and the autobox.

The automatic is much less forgiving of mis-matched ratios between the gearing and the tire size than a manual. So you need to stay close to the same effective final drive ratio as you go to larger tires.

Stock tire size is close to 29 inches, and lets say your tranny can probably tolerate 31's with stock gears.

For 33s you'll be at 4:56 and with 35s you'll be around 4.88s. The doubler or Marlin Crawler does not change any of this, since unless it's in low, it's still straight through 1:1.

Besides the sluggish performance with the wrong gearing, the issue with the tranny is a major one. The slightest incline will cause it to unlock the lock up and shift into 3rd or even 2nd. That's when it generates the most heat, and does the most long term damage. A tranny cooler would help a little, but TrickyT has some data with his FJ62 and a cooler that makes you realize that the tranny will still run hotter than you want. An extreme valve body would help, since it can lock up in 3rd, but I can't see putting a nice piece like that in a high mile transmission like you have. Search around on the 3FE list or here for Rodney's comments on the heat issue.


I would start with the tire size and work backwards, keeping in mind you want the tranny to "see" close to stock load and RPM numbers. If you plan to run 35s, and no reason to SOA if you don't, then basically you have to run 4.88 gearing. You saw my 80 at SnT-to keep the tranny happy with the 35s I had to gear it to 4.88 even though that tranny can lock up in 3rd.

If you swap in a manual tranny, it's always "locked" and so doesn't have the heating/load issues of an incorrectly geared auto. With a manual, 4th gear, 4.11s and 35s is very acceptable on the freeway, and not bad for the tranny or the motor.

 

[Randy88FJ62]

What you're telling me is that I have to pony up to 4.88's and there's no way around that. I expected it but was still looking at alternatives. That seems to be the easiest approach.

 

[Cruiserdrew]

What you're telling me is that I have to pony up to 4.88's and there's no way around that. I expected it but was still looking at alternatives. That seems to be the easiest approach.

I think it's the easiest/cheapest/best approach as well, cheapest as in relative to a new transmission. That extreme A440F is cool though.

You're learning fast how one modification generates another, and requires yet another. This is normal. In the middle of a build, it can feel like throwing $100 bills away in the wind.

It's also why the guys that say they did their spring overs for $35 and a 24 pack of Keystone Light are full of crap.

You could swap in a manual tranny-that's work and money too, but it will give you more long term options.

 

[PPFJ60]

Just to let you know how the modifications can add up, my $50 NP203 cost $1300 by the time I was back on the road. $450 was for a tranny upgrade while it was out but I would not have done that if the tranny had not been dissassemble to replace the output shaft.

 

[Randy88FJ62]

I have a spare FJ62 drivetrain and another spare A440F so I have parts to burn. No way I'm going manual. I purposely went with the 62 because of the auto and fuel injection.