Ramblings about doubler options (1 Viewer)

Lil'John

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The only thing I like about the doubler is the lower low. With the Rockbox I'm looking at, it will be right about 200:1 in first, vs an Orion at 115:1 in first.
At a certain point, it is just measuring d's;)

My experience on the Rubicon in an FJ40 with ~60:1(SM465, lc case and 4.11 gears) with 35s showed me it wasn't quite deep enough. My ride-along with exact same rig but the doubler showed it to work well.(Both V8s)

For the money, I would just go split case + AA gears over an Orion every day. Quieter and significantly stronger.

FWIW, the stock Dodge NV4500 output housing is much shorter than the Chevy version(~2") Think 4" vs 6"... I can't find exact numbers right now.
 

mr jits

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Its an old AA product. 3.44 low. Not in production anymore which makes parts hard to find. I'm kind of apprehensive about it, but it's a good price, and most likely rebuildable.
So is there one available? I'm typically apprehensive about a driveline component that's no longer in production.
 

DangerNoodle

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So is there one available? I'm typically apprehensive about a driveline component that's no longer in production.
I have a guy that is looking to sell. I haven't really seen any gripes about them, but they look pretty strong and this one is supposedly pretty low miles. I do worry about breaking it, but I can always pull it out and lengthen the driveshafts.
 

GLTHFJ60

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My experience on the Rubicon in an FJ40 with ~60:1(SM465, lc case and 4.11 gears) with 35s showed me it wasn't quite deep enough. My ride-along with exact same rig but the doubler showed it to work well.(Both V8s)
FWIW, 4:1 in my dana 300 wasn't enough for me. Low range was too slow for bopping around trails, and too fast in the rocks. I wasn't a fan. I'm much happier with a doubler setup than I ever was with a single case.

Late edit here: I think this is heavily dependent on tire size. I've been on 42s for a few years, and 39.5s for a bit before that. Before that, 37s and 35s. 4:1 may well have been plenty with 37s or lower, but with the bigger tires, I didn't think it was enough. Just putting my experience in context.
 
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cruisermatt

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I would avoid ANY NP203 based doubler like the plague. They add a TON of slop to the drivetrain. The shifter in my experience has problems staying in gear(two different rigs) I swapped out an NP203 to a plain split case behind an NV4500.
and now it's in my rig, thanks :flipoff2:
Now that I have a quiet Nv4500 I can hear the doubler on decel. :p
 
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I was interested in putin in a rock box years ago when they were the thing to do and then the Toy box was there .i went with the Toy box it works good enough for me . Alec had his before me and he's good with it, his 4 speed is a SM420 and mine is a 4 speed out of a 87' FJ60.
 

DangerNoodle

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I was interested in putin in a rock box years ago when they were the thing to do and then the Toy box was there .i went with the Toy box it works good enough for me . Alec had his before me and he's good with it, his 4 speed is a SM420 and mine is a 4 speed out of a 87' FJ60.
I'd really like to find a toybox, as I believe that parts are more available, but Marlin isn't making them any more which really sucks. Havent seen any for sale either.

I guess I'll take whatever I can get my mitts on, though.
 

DangerNoodle

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Really wish @Marlin Crawler would produce the toy box again or at least do group orders of them. 100% would have gone that way instead of the 4:1 gears in my splitcase. I’ll still only be at 68:1 even with 4:1 gears where as a toy box would have yielded 152:1...
I feel the same way. For basically the same price, you get a lot more options with better reductions.
 

GLTHFJ60

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Not to mention driveshaft mods, cross member mods/additions, spacial constraints, etc. A crawlbox, toybox or not, is way way way more expensive than low range gears.
 

DangerNoodle

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Not to mention driveshaft mods, cross member mods/additions, spacial constraints, etc. A crawlbox, toybox or not, is way way way more expensive than low range gears.
True. I was just looking at my assumed cost of the box. Didn't really think about eveything else.
 

DangerNoodle

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Ok.... I've reached a point where I don't believe that the seller of this Rockbox is willing to really sell, so I'm back to looking at options.

A toybox seems like it would be pretty simple to do. It would need custom adapters, but I think that could be figured out. My problem is that I cannot find an NV4500 to 21/23 spline tcase adapters. It looks like AA used to make one, but not anymore. Do you guys think that this is worth the time to look at seriously doing?
 
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DangerNoodle

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Can you adapt your NV4500 to a NP203, then use this in front of your current 16 spline case?

I don't quite have the length, plus I have heard that the NP doublers are really loud.
 

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