Marlin Crawl Box. Should I? (1 Viewer)

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@Rattlewagon do you run the Advance Adapters doubler ? Or anyone else looking for opinions on them

Thanks
 
Its totally worth it. Im running a doubler with 2.28/4.7 gears and the options are awesome.

Check out Advance adapters for the doubler adapter. you can get them through poly preformance for around $370 I think.

Heres my 2.28/4.7 full 23 spline doubler to go behind a v6
BeaC6FBl.jpg


Driveshafts made from 2.5"schedule 40 fit the stock joints well.

vzYxu0Ol.jpg


Happy to answer any doubler questions, Ive done a few of them.

This is a marlin doubler that is clocked 10* that I did a few months ago.

Yqb9GrMl.jpg
Curious, what is the reason for the “clocking”
 
x2 what z said. the 10* adapter moves the front output up about an inch. Does increase angles slightly, and a high pinion front diff will do wonders for front ds angles. It also make it difficult to use an off the shelf skid/cross member as the rear mount in 10* off. We only used it because its what came with the pile of parts he bought.

@VA.CRUISER Yes, both my 3.0/gear drive adapter and the dual case adapter is from Advance. Very happy with them. Great product and great customer service.

so.. I toasted my 4.7 gears in my rear case a few weeks ago at f&f on a blue trail believe it or not. They were 6 years old and apparently they were all done. No bearing or case falure. I was able to put the rear case in "hi" and drive out with minimal crunching.

hR8ddYml.jpg


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I replaced with SUMO 4.7 gears ( also through advance adapters ) Shipped to my door in a week, and supposedly stronger than TG gears. I have a sumo 23 spline input in my front case for a few years now and have no complaints.


v4uzW8al.jpg


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Thanks @Rattlewagon strongly thinking of buying one this weekend with the discount 😎
 
You don’t have to change the gears you can run stock/stock
 
I run both Cases with stock gears in my buggy with 5:29 and 39” bfgs. Plenty slow. I never take it out of low/low. 4th gear is like 1st in low only.
 
I run both Cases with stock gears in my buggy with 5:29 and 39” bfgs. Plenty slow. I never take it out of low/low. 4th gear is like 1st in low only.
Ok cool. I just got my 5.29’s installed last week and I’m on 36 Tsl radials. So duel cases with stock gears is plenty probably since I have smaller tires too
 
You need a gear drive top shift transfer case, or convert a front shift to a top shift. and an adapter, new drive shafts, and some floor board modification. in a nut shell.

Always fun to break down the crawl ratio.

(1st gear in trans) x (front case)x(rear case)x (axle gears)

My ratio is (r150f) 3.83x2.28x4.7x4.10 = 168.

If you had a w56, it would be 3.95x2.28x5.29 = 46 right now , stock duals 3.95x2.28x2.28x5.29 = 108 , or ultimate duals 3.95x2.28x4,7x5.29 =223

Of course it doesn't account for tire size or engine torque, but helps break it down a little.

the other nice thing about the 4.7 is it turns it into a 4 speed case. 1st is high 1:1, then stock low 2.28, 4.7 then double low of 10.7:1. 20 forward gears and 4 reverse gears. Where as with stock duals, its a 15 speed, with 3 reverse speeds.

"dual ultimate" gear layout

Black is transmission/transfercase gear ratio, red is what gear "overall"

fU1vLrml.jpg


stock duals

y5kPLipl.jpg


" . 4th gear is like 1st in low only. " looks like its closer to 2nd. lol. .

I mentioned adding gears to the front case, because my truck is a v6 so I had to convert everything to 23 spline. you wont have to do that for 4 cylinder (21 spline)
 
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I run both Cases with stock gears in my buggy with 5:29 and 39” bfgs. Plenty slow. I never take it out of low/low. 4th gear is like 1st in low only.
Also just found an 87 transmission and transfer case
You need a gear drive top shift transfer case, or convert a front shift to a top shift. and an adapter, new drive shafts, and some floor board modification. in a nut shell.

Always fun to break down the crawl ratio.

(1st gear in trans) x (front case)x(rear case)x (axle gears)

My ratio is (r150f) 3.83x2.28x4.7x4.10 = 168.

If you had a w56, it would be 3.95x2.28x5.29 = 46 right now , stock duals 3.95x2.28x2.28x5.29 = 108 , or ultimate duals 3.95x2.28x4,7x5.29 =223

Of course it doesn't account for tire size or engine torque, but helps break it down a little.

the other nice thing about the 4.7 is it turns it into a 4 speed case. 1st is high 1:1, then stock low 2.28, 4.7 then double low of 10.7:1. 20 forward gears and 4 reverse gears. Where as with stock duals, its a 15 speed, with 3 reverse speeds.

"dual ultimate" gear layout

Black is transmission/transfercase gear ratio, red is what gear "overall"

fU1vLrml.jpg


stock duals

y5kPLipl.jpg


" . 4th gear is like 1st in low only. " looks like some where between 2 and 3rd.

I mentioned adding gears to the front case, because my truck is a v6 so I had to convert everything to 23 spline. you wont have to do that for 4 cylinder (21 spline)
Is this the case I need?

5BC74C39-7149-4C1B-B642-2DC5080558AF.png
 
Count the bolts on the rear output . 7 bolts for gear drive, 5 for chain. (You want 7) Thats a foward shift case (rails come out the front vs a shifter out the top) it will work, but you would have to convert it to a top shift. People make kits for that.
 
I actually run forward shift up front and top shift in back. The 94 donor truck came with forward shift That’s why it was easy to make it work. I left the shifter in stock location which is in back of transmission. Just had to weld the shift fork window closed.
 
Count the bolts on the rear output . 7 bolts for gear drive, 5 for chain. (You want 7) Thats a foward shift case (rails come out the front vs a shifter out the top) it will work, but you would have to convert it to a top shift. People make kits for that.
Well turns out it is $50 and it is a 7 bolt which is good. But the convert kit from TG is $250! Not including shipping. Think I may pass on this one and wait for the right one ...
Thoughts?
 
Waiting is a better choice. Look on www.car-part.com - that t-case ranges from $100-$300 here in New England.

The t-case in your pictures will also need a rebuild given the bearings being covered in dirt and dust. I've bought used t-cases from the recycler that I could use as is.

Nick
 
@Trialsallday if you’re interested in the adapter Poly Performance has a Labor Day 20% off use LABOR20. I just ordered a Advance Adapter TX-2 for $340 😎 thanks for some advice @Rattlewagon
 

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