Yea for some reason I think all doubler cases like to spit oil out of the breather, my Marlin case is reallllyyyy bad. Lost about a quart over 2k miles lol. Will be switching to the NWF case in the near future because I want to switch back to oem gas tank in order to use the 4wu rear underbed coilover kit when I go tons and 40’s as well. Where are you getting your axles from out of curiosity? Going to keep it streetable/registered?

I just re routed my breather tube to inside the cab, hopefully it doesn’t start puking out all over my interior. Lol.

Check the oil levels in all three cases (trans, doubler, transfer) if you keep getting oil spitting out of one of them. My wife's did this on our first trip with her Tacobox Marlin doubler. We didn't think much of it at first, maybe it was just a little over filled. Like the front diff's and spit a little oil out the breather if you fill it up.

Turns out the seal Marlin sent her for the trans wasn't right (which they finally admitted, after sending her a new one that looked different) and it was letting oil move from the trans to the doubler case, overfilling it. This didn't happen much driving around town, but take it on the highway for hours on end?

So, unfortunately, did didn't know how much oil came out, didn't worry about it as much as we should have during the trip, and the trans (new rebuilt one too) went dry and got noisy. Discovered that too late and added oil, and limped it back home, but it needed another trans after that. And another seal that actually sealed.

That’s what I was thinking at first but I’ve drained/refilled the marlin case and no red trans fluid at all(auto trans). Also checked trans fluid and looks just as fresh as when I changed it 4-5k miles ago, no signs of gear oil. Don’t really know what to make of it, when I talked to the NWF guys they said the Marlin cases build up pressure and like to puke fluid which is what seems like my case. The other factor is I’m going 70-80mph with 35’s and 5.29’s which is probably over spinning the crap out of the case lol. I feel if I had 37-40” tires I wouldn’t be seeing nearly as much fluid being puked out, who knows..

Axles (both front and rear) are from a 2004 SuperDuty. I went with these axles for a few reasons, I wanted tons but didn't want to go as wide as the 05+ SD axles (the 99-04 SD axles are narrower), the rears have a super cheap OEM e-locker, and they have a ton of aftermarket support.

Yes, it will be California smog legal and streetable. I'm getting close to finishing the front (well, finishing it close enough to roll it out of the garage). Some pictures of it at full bump (yes, clearances are very tight):

Attached Images

       

I believe I have the first Marlin Crawler Lefty put behind a Toyota V8. It was upgraded with Marlin's "Competition" gear set that may be the reason it's lasted all this time without breaking. It also has the 30 spline output shafts that were a pretty new upgrade when I got mine (2009).

The case is strong but I would disagree that Lefty's are stronger than the newer chain cases. I think an FJ Cruiser case with a taco box is probably a stronger setup.

The main reason I went with the Lefty was the size. It went right into my 4runner without needing to modify the fuel tank. The only modification to the floor board was making the hole for the twin-stick to come up through. It even allowed me to keep the 4wd light working in the dash.

The lower range is a significant advantage over stock but you can hear some gear-whine being a geared case.

I've had it behind the V8 and pushing Dana 60's with 40inch tires and it's held up all this time. I think it's also how I drive, I try to crawl and always try to limit wheel spin with the skinny pedal.

I'm moving to a Behemoth D300 4 speed but it's nearly 4 times as expensive. This will also be new territory since I haven't found anyone else who's tried to put one behind a Toyota A750f trans yet.

It would be cool to see Marlin Crawler or Inchworm produce the Lefty again because I think it's a good case depending on what you're building. If you want strength though, I still think a twin-stick FJ case with a taco box is stronger if you can make it fit.