Just Scored Unobtanium! - Marlin Crawler Rebuilt R151F Trans and RF1A T-Case (1 Viewer)

Will Van

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Mine is in a 1992 ln106

Thank you for the link to the OD 5th gear.


Man, I wish the USA got the later-model Hilux. They are so badass.
1920px-1995-Toyota-Hi-Lux-4-X4-Diesel-2-5-Front.jpg


1920px-1995-Toyota-Hi-Lux-4-X4-Diesel-2-5-Rear.jpg
 

pappy

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Question. Are the output shafts interchangeable between early and late R's? Could one source a late shaft, and the Dyna gear, and transplant into the early R-series?
 

Will Van

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Question. Are the output shafts interchangeable between early and late R's? Could one source a late shaft, and the Dyna gear, and transplant into the early R-series?

Great question. If they were interchangeable, you could source the late-model output shaft and make swapping the Dyna gear possible since it would have the c-clip instead of the nut and pressed-on 5th gear.

"A few people have mentioned to me that they could not get the 5th gear off the output shaft as it is pressed on. It seems that if you have the older R series with the nut on the end of the counter shaft then this mod becomes more difficult. On my R series (circlip on the output) the 5th simply slid off and on by hand. I went back to the R151 manual linked above and found that the 5th is indeed pressed on for these older model R series."

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Mine is in a 1992 ln106

Can’t wait to do this swap one day if I can score a 2lte bellhousing in the states but the manuals are a rare bird. The LN106 is not geared well for our interstates out west
 
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If swapping outputs is unknown what about swapping input shafts from Pre 95 R15X to later model?
 
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I'd get the total spline 23 spline input shaft from Marlin for the rear box. And I'd put the 4.7 gears in the rear box and 2.28's in the crawler box. If you put the 4.7's in the crawler box then the multiplication torque is going into the input shaft of the rear box. Not really ideal when you can just put them at the last chain of output.

I'd probably also CSI your usage requirements ensuring you'll actually need 10.7 total low range..... dual 2.28's at 5.2 is pretty low! 2.28 and 4.7 at 10.7 is like....holy low and slow. Major rock crawling trails all day kind of low. Might save yourself the money and keep er dual 2.28's? Although I suppose having 10.7 at the t-case could make up for a high geared diff if that was the intention.
4x4wire reveiw of the 4.7 gear set suggests there's more slop in the gears... A reason I wouldn't bother going with 4.7's for sh*ts n gigs.

Food for thought, anyhow.
 
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pappy

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I'd probably also CSI your usage requirements ensuring you'll actually need 10.7 total low range..... dual 2.28's at 5.2 is pretty low! 2.28 and 4.7 at 10.7 is like....holy low and slow.

This. I have dual 2.28 and have never needed more. IMHO, 2.28 + 4.7 is marketing hype and a conspiracy to seperate you from your money. It's also something you can brag about to your buddies. I guess under extream rock crawling it might be useful, but I just can image where 2.28 + 4.7 + 1st gear could be practical.
 

Will Van

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I'd get the total spline 23 spline input shaft from Marlin for the rear box. And I'd put the 4.7 gears in the rear box and 2.28's in the crawler box. If you put the 4.7's in the crawler box then the multiplication torque is going into the input shaft of the rear box. Not really ideal when you can just put them at the last chain of output.

I'd probably also CSI your usage requirements ensuring you'll actually need 10.7 total low range..... dual 2.28's at 5.2 is pretty low! 2.28 and 4.7 at 10.7 is like....holy low and slow. Major rock crawling trails all day kind of low. Might save yourself the money and keep er dual 2.28's? Although I suppose having 10.7 at the t-case could make up for a high geared diff if that was the intention.
4x4wire review of the 4.7 gear set suggests there's more slop in the gears... A reason I wouldn't bother going with 4.7's for sh*ts n gigs.

Food for thought, anyhow.
This. I have dual 2.28 and have never needed more. IMHO, 2.28 + 4.7 is marketing hype and a conspiracy to separate you from your money. It's also something you can brag about to your buddies. I guess under extreme rock crawling it might be useful, but I just can image where 2.28 + 4.7 + 1st gear could be practical.

Sorry, I haven't updated this in a while since I have been focusing on my build thread for the 4Runner.

There are a lot of moving parts to this dual case conversion, so I'll try to be as clear as possible.

I bought the Marlin rebuilt R151F transmission and Marlin rebuilt 2.28 transfer case from a buddy with zero miles. The Marlin t-case is forward shift and already has a 23-spline input shaft to mate to the R151F. And it also has the upgraded Marlin 30-spline heavy duty front and rear output shafts on the rear housing. Edit: I’m wrong. I went back and measured the output shaft diameter. The Marlin rebuilt t-case only has the heavy duty flanges, not the upgraded 30-spline output shafts.

If I want to run dual cases, I'm going to have to split the Marlin t-case either way. And the front half of the front case should be the Marlin 2.28 case (to run the forward shift portion of the case on the R151F). And the rear half of the second rear t-case should have the Marlin 30-spline output shafts.

That leaves us with the rear transfer case. I picked up a used top-shift t-case with zero history. I wanted to rebuild it anyway, because I didn't know the condition. So I just splurged for the Marlin 23-spline 4.7 gear set, since it's basically a complete rebuild kit anyway. And I bought the 23-spline Marlin dual case adapter, so I'm running 23 splines in both cases. I will probably get FROR twin-stick kit so I can run 2WD/4WD and Hi/Low separately.

It's true, the 10.7:1 t-case gearing is super-low. But I don't have to use all that gearing. It just affords me a lot of options. Plus, I'm not obligated to use 1st gear in the R151F.

I suspect (but don't know for sure since I bought the R151F second-hand) that the transmission has the 3.83 1st gear option based on what the Seller told me.

So these are the final drive options I will have in 1st gear if I keep the 4.10:1 diff gears:

Front Case High, Rear Case High = 15.7:1 Final Drive
Front Case Low, Rear Case High = 35.8:1 Final Drive
Front Case High, Rear Case Low = 73.8:1 Final Drive
Front Case Low, Rear Case Low = 168.3:1 Final Drive

With the OM617 diesel, 33" tires, and 4.10 diff gears, I will have a wide variety of options - from keeping everything in high and getting great mileage on the highway, to fully low-low and being able to crawl over anything at diesel idle. Plus all the options in-between.

Overall, I'm pretty excited about how this is going to turn out. With a rear locker the 4Runner should be unstoppable. But I've got some other maintenance items to address first (brake master cylinder, rear axle seals, tires, etc).

Right now I'm just waiting on the dual case adapter to ship from Marlin, then I can start tearing into the dual case build.
 
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Will Van

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R151F should be 4.13 first gear.

...unless the Seller I bought the R151F from chose the 3.83 1st gear option when he bought the rebuild from Marlin. Which is highly likely due to the nature of his V8 build.
 

Will Van

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I need a pickup. Maybe this R151F should go in a 75 series or 79 series? Can you mate a 1HZ to an R151F out of a mini-truck?

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For the Pickups, it seems like most people are just buying the cab/bed body separately, and then stretching an 80 series frame to mount it on?
 
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I don’t think the transfer case will work. I think the diff flanges and drive shafts are in-line.
 
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The split case setup loses the crawl box and RF1a transfer case. Needs to go in something with mini truck axles.
 
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They are both offset to the same passenger side. So the driveshaft is in a single line. The mini truck or 4runner front is offset to the passenger but the rear is in the center. Not sure if that applies to all land cruisers.
 

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