Ford doubler/underdrive tech

[Hyde]

So after my first trip with my Ranger I'm looking harder at doublers. Current setup is 4.0/np435/205, D60/14 bolt with 4.10s and 38s. I definitely need more gear and would rather not gear the axles.

​​​​I'm capable of re-gearing but would like to avoid it, if you've seen my build thread I'm using a 32 spline Dodge 60, I don't want to buy gears for the low pinion axle because if I break basically anything on it I'm buying a SD 60 and the gears wouldn't swap.

On to my question, what's everyone doing for 31 spline input doublers?

203/205. If I can source a Ford 203 the doublers are reasonably priced, I would prefer to have 3 speeds though so that's not my first choice. Also Ford 203s aren't falling out of every truck heading to the junkyard anymore.

Behemoth, well they are Behemoth. If it was made by a reputable company an underdrive utilizing Borg Warner planets would absolutely be my first choice. Is there anybody else building these that I just haven't been able to find?

NWF eco box. NWF has a great rep, I'm not big on extra machining due to using NP planets, anyone know what the machining entails and approximate cost to do so? NP planets aren't nearly as common as the Borg Warner stuff in my searching, plus the extra machining, makes it hard to put this as my first choice. The Titan just has a far higher price tag than I'm looking for with this build.

As far as I know DD/Duffy is out of business, Jed's website hasn't been maintained so not sure if they are in business either. Are there any options my Google-fu hasn't turned up that are Ford friendly?

 

[Toreadorranger]

I have a doubler in my build right now, but mainly because I got the 203/205 already doubled together for really cheap. If it were me I would have went with the titan or Eco-box. NWFs new Eco-titan looks pretty good, although with the extra machining I'm not sure its worth saving the $700 and not just getting a complete ready to run unit.

I most definitely would not order from Behemoth. They are the modern day Ballistic Fab, If you like spending money and not getting what you bought Behemoth is your place.

 

[Scott Cee aka 2drx4]

If you're sticking with the anemic 4.0 I would get an Eco-Box and not look back. The NP271 F is super common and has the correct 31 spline input, and I think you can use the planetary setup from it... I could be wrong on that though, but later model GM 241s are dirt cheap and those planetaries should be the same cut as the 271, so it should work together. NP/NV tcases are generally fairly interchangeable between years, assuming you don't mix the 94 and earlier gear cut up with the 95 and later. The 31 spline input is also readily available on the internet from retailers for around $100.

 

[ANGELO]

As far as I know DD/Duffy is out of business, Jed's website hasn't been maintained so not sure if they are in business either. Are there any options my Google-fu hasn't turned up that are Ford friendly?

I just bought a jeds doubler kit. they are still in business

 

[Hyde]

If you're sticking with the anemic 4.0 I would get an Eco-Box and not look back. The NP271 F is super common and has the correct 31 spline input, and I think you can use the planetary setup from it... I could be wrong on that though, but later model GM 241s are dirt cheap and those planetaries should be the same cut as the 271, so it should work together. NP/NV tcases are generally fairly interchangeable between years, assuming you don't mix the 94 and earlier gear cut up with the 95 and later. The 31 spline input is also readily available on the internet from retailers for around $100.

I have a mustang 5.0 on the shelf for when the 4.0 gives up, not that they are huge power or anything.

Anyone done the eco box that knows exactly what machining you have have to do for the 31 spline input?

 

[Scott Cee aka 2drx4]

I have a mustang 5.0 on the shelf for when the 4.0 gives up, not that they are huge power or anything.

Anyone done the eco box that knows exactly what machining you have have to do for the 31 spline input?

The 5.0 is still well within the power that the Eco-Box will take.

Have you asked NWF? I know that's a weird solution, but they do actually know a lot about their product and are pretty willing to talk on the phone.

 

[Hyde]

I haven't talked to NWF, that would be a decent place to start. I try not to tire kick and waste a companys time unless I have the cash ready to buy but I'm sure they could tell me

 

[total newb]

Ord may not make the ford/dodge bolt pattern clocking but they have a fully contained box.

Prob not the easiest or cost efective but ford 203 seem to be common around hear right now. But honestly by the time i get you one ship it and the adapter cit your into the ord/nwf $$ range without the headaches.

 

[arse_sidewards]

I'm planning on a NP203 in front of a NVG271 in my Ranger. Considering the kind of power the diesel guys put through it I am not at all worried about the 271 standing up to a sub-500hp engine and a 2:1 reduction.

You might want to consider an BW1356 doubler. The case is easy to cut and weld, decently short, you can make the block off plate yourself and you only really wind up paying big bucks for the custom shaft.

 

['84 Bronco II]

203/205. If I can source a Ford 203 the doublers are reasonably priced, I would prefer to have 3 speeds though so that's not my first choice. Also Ford 203s aren't falling out of every truck heading to the junkyard anymore.

NWF eco box. NWF has a great rep, I'm not big on extra machining due to using NP planets, anyone know what the machining entails and approximate cost to do so? NP planets aren't nearly as common as the Borg Warner stuff in my searching, plus the extra machining, makes it hard to put this as my first choice. The Titan just has a far higher price tag than I'm looking for with this build.

These are the two options that I would go with in your situation. I wouldn't worry about having the low range in the crawl box be the same as the low range in the transfer case. There is not enough difference between the 2:1 in the NP205 and the 2.71:1 in the NP planetaries to be worthwhile in my opinion. I have a Behemoth 1350/1354 setup in my Bronco II which gives me 1:1, 2.48:1, and 6.15:1 in double low. Even with "only" two low range ratios, I still have 3 overlapping gears in each range (I have a 5 speed), and I don't ever find myself wishing for something between the 2.48:1 and 6.15:1.

My Behemoth box has been great, and my experience, as well as a buddy of mine who also bought a doubler from them, were not a complete nightmare like a lot of the stories you hear about. That said it did take us both a month or two to get our parts, but I bought mine about 6 years ago or more, and he bought his about three years ago I think, so things very well could be worse now. The nice thing about Behemoth as you pointed out is that you can just use a 31 spline Ford planetary and not have to screw around adapting a 31 spline input like you have to with a NWF box. Aside from that issue though, with the NWF box only being modestly more expensive and their great reputation, my next doubler will be a NWF unit. If you do go that route, I would be really interested in seeing what it takes to get one behind a Ford NP435.

 

[Toreadorranger]

You might want to consider an BW1356 doubler. The case is easy to cut and weld, decently short, you can make the block off plate yourself and you only really wind up paying big bucks for the custom shaft.

The standard 1356 case is magnesium, so pretty much a no go on the welding front. He would need to find a BW1356 with PTO, those have aluminum cases.

 

['84 Bronco II]

The standard 1356 case is magnesium, so pretty much a no go on the welding front. He would need to find a BW1356 with PTO, those have aluminum cases.

Also, the full-size chain drive cases don't fit the greatest between RBV frame rails. I have a 1356 in my beater Bronco II, and while the 2.69:1 low range is nice compared to the NP205 low range, I wouldn't hack up my frame to put one in if I already had a 205.

 

[Toreadorranger]

Also, the full-size chain drive cases don't fit the greatest between RBV frame rails. I have a 1356 in my beater Bronco II, and while the 2.69:1 low range is nice compared to the NP205 low range, I wouldn't hack up my frame to put one in if I already had a 205.

I think the reference was more to using the 1356 as a crawlbox in front of the NP205, not to run it as the rear case.

 

[arse_sidewards]

The standard 1356 case is magnesium, so pretty much a no go on the welding front. He would need to find a BW1356 with PTO, those have aluminum cases.

It's an aluminum magnesium alloy. Get it stupid clean, preheat and stitch it together one fat tack at a time with these.

https://www.amazon.com/Blue-Demon-ER.../dp/B00I4WXWD8

Or braze it.

I think the reference was more to using the 1356 as a crawlbox in front of the NP205, not to run it as the rear case.

Exactly. Hence why you'd need to weld it.

 

[Toreadorranger]

It's an aluminum magnesium alloy. Get it stupid clean, preheat and stitch it together one fat tack at a time with these.

https://www.amazon.com/Blue-Demon-ER.../dp/B00I4WXWD8

Or braze it.



Exactly. Hence why you'd need to weld it.

hmm, that's good to know, I just assumed it was a no go. That would be a viable option for a crawl box then. They are dirt cheap. I can't give away the one I pulled from my F-250. Manual shift slip yoke 1356s would make a great donor for this.

 

['84 Bronco II]

I think the reference was more to using the 1356 as a crawlbox in front of the NP205, not to run it as the rear case.

Ah, I don't know why I was thinking he was talking about a 1356 crawl box in front of another 1356. That makes much more sense, but the last time I saw people talking about doing home-built doublers, the intermediate shaft was so expensive you might as well just buy one of the doubler kits and not have to screw with building your own adapter plate and welding up the housing. Of course, you can always weld your own intermediate shaft, but without machining interlocking features and or a press fit before welding it is pretty dicey strength-wise and hard to control runout.

hmm, that's good to know, I just assumed it was a no go. That would be a viable option for a crawl box then. They are dirt cheap. I can't give away the one I pulled from my F-250. Manual shift slip yoke 1356s would make a great donor for this.

Just make sure you have sand or a fire extinguisher rated for burning metals on hand just in case You definitely don't want to try and put it out with water.

 

[Hyde]

Thanks for all the input guys. I'm not ready to buy yet anyway so I think I'm going to pick up a cheap 1356 and mock it up with the full length main shaft to see just how long it will be (it looks very long in pictures), my rear driveshaft is damn near 5 feet long so I have room to play with.

If it will fit i can build the adapter on the bench with my spare 205 and swap it in this winter, I just got it put together I don't want to tear the rig back apart yet

 

[subybaja]

Someone mentioned a while back that they got a shaft for a DIY 1356 hack-off doubler from...Behemoth. For $250.

Here, because fuck Canada, is a Chinese thread my buddy did about using a full-length shaft in his full-length truck. It worked OK, if you didn't mind being a block long. He never got the mounts figured out, and kept twisting the box off of the trans.

http://www.4x4-16.com/BW-1356-double..._10209747.html

 

[Hyde]

Someone mentioned a while back that they got a shaft for a DIY 1356 hack-off doubler from...Behemoth. For $250.

Here, because fuck Canada, is a Chinese thread my buddy did about using a full-length shaft in his full-length truck. It worked OK, if you didn't mind being a block long. He never got the mounts figured out, and kept twisting the box off of the trans.

http://www.4x4-16.com/BW-1356-double..._10209747.html

This setup is pretty much what I'm leaning towards for the poor boy points. It would be significantly shorter with my 205 as the rear case. I could keep my current trans mount and build another crossmember with a mount on the 205 to support the whole thing.

That thread will be my easy reading for the night

 

[Gravy]

Iv got a 1354/205 doubler and it works great. While trail running Im using the 205 in 2wd low and kick it in/out of 4wd.
Unless you are on a tight budget I would go atlas or 205doubler. After the dust settles you will have more $ doing a junkyard case.

 

[Gravy]

Also you need to commit to gearing your axles it will make the biggest difference. With the deep 1st in your transmission and 5.38 gear you may get way with no doubler.

 

[subybaja]

This setup is pretty much what I'm leaning towards for the poor boy points. It would be significantly shorter with my 205 as the rear case. I could keep my current trans mount and build another crossmember with a mount on the 205 to support the whole thing.

That thread will be my easy reading for the night

re: mounts
As long as it's a triangle. Your engine is GOING to move. I guess two rear mounts would work as long as they're in a longitudinal line, so the whole mess can still pivot on them.

WhiteRunner never got that, and his rear hardmount just twisted the whole stack apart, between engine torque and frame flex. Then he caught Toyota.

 

[arse_sidewards]

Someone mentioned a while back that they got a shaft for a DIY 1356 hack-off doubler from...Behemoth. For $250.

Here, because fuck Canada, is a Chinese thread my buddy did about using a full-length shaft in his full-length truck. It worked OK, if you didn't mind being a block long. He never got the mounts figured out, and kept twisting the box off of the trans.

http://www.4x4-16.com/BW-1356-double..._10209747.html

That's exactly the build I thought of when he mentioned he had a 5ft rear driveshaft and plenty of space. Nice choice of link

re: mounts
As long as it's a triangle. Your engine is GOING to move. I guess two rear mounts would work as long as they're in a longitudinal line, so the whole mess can still pivot on them.

WhiteRunner never got that, and his rear hardmount just twisted the whole stack apart, between engine torque and frame flex. Then he caught Toyota.

Of course the guy who builds that trans mount and thinks it's good to run moves on to Toyotas.


FWIW the Ford NP203 tailhousing for the C6 uses a pair of mounts that are like 8-10" apart. I think it's ghetto and just asking to break shit considering the floppy frames in the trucks those went in but I guess it works. I personally see no reason to use four mounts when you can just make a foot on the doubler tailhousing and bolt an OEM trans mount to it.

 

[Toreadorranger]

The Doubler mounting question is such a crap shoot. Some people get away with 1 mount and others seem to break transmission tailhousings every time they drive. When I started my doubler install, I decided to run the dual mount with the bushings inline with each other. I have a single round poly bushing in place of the OEM transmission mount. My plan is to make a 2nd crossmember that mounts off the rear output of the 205 and then tie the two crossmembers together to make a belly pan/skidplate. I planned it this way mainly because of the weight of the 203/205 combo.

 

[arse_sidewards]

The Doubler mounting question is such a crap shoot. Some people get away with 1 mount and others seem to break transmission tailhousings every time they drive. When I started my doubler install, I decided to run the dual mount with the bushings inline with each other. I have a single round poly bushing in place of the OEM transmission mount. My plan is to make a 2nd crossmember that mounts off the rear output of the 205 and then tie the two crossmembers together to make a belly pan/skidplate. I planned it this way mainly because of the weight of the 203/205 combo.

There's so many variables. My hunch is that a lot of the people who are breaking things are running floppy motor mounts and between that and all the frame flex they are running out of travel in the trans mount.

 

['84 Bronco II]

Also you need to commit to gearing your axles it will make the biggest difference. With the deep 1st in your transmission and 5.38 gear you may get way with no doubler.

I imagine Hyde isn't too concerned about streetability with this truck, but the nice thing about keeping the axle ratios high is that it keeps cruising RPM down on the highway with the NP435 since there is no over drive. You can use 1st with the NP435 to take off to compensate for the 4.10s in the axles so that you can actually use the four speeds on the street

Even going to 5.38 axles from 4.10s won't be nearly as dramatic of a gear reduction as running a doubler, or hell, even just running a Borg Warner transfer case. Currently his crawl ratio is sitting at ~54:1, which is garbage, and 5.38s would take him to ~71:1 which is decent, but not great for really technical stuff, especially without V8 torque. Simply swapping a BW1356 in place of the NP205 and keeping the 4.10s would put him ~74:1 which is exactly what I am running in one of my rigs (5.0L, NP435, BW1356, 4.10s, 38s). With V8 torque, 74:1 is good enough most of the time, but when things get really technical, I would really like to be lower. A standard NP203/205 doubler setup would put him at ~108:1, which would be about perfect with a V8. With the 4.0L, he still might want a little deeper. Using a NWF box with NP planetaries (2.71:1), he could be at ~146:1 with the 4.10s, which would be all the gear reduction he could ever need while still having excellent cruising RPM on the highway. A Borg Warner Planetary would give him a very similar crawl ratio.

As for mounting the doubler, I would definitely add a second mount (and did on my build). Just make sure to use flexible mounts (rubber or polyurethane) and you will be fine. Hard mounting like the picture that was posted is a terrible idea and will make something break. The only time you could really get away hard mounting drivetrain is if you have an extremely stiff chassis like a tube buggy, otherwise, something will have to give, and it will usually be the brittle cast parts.

 

[Gravy]

I imagine Hyde isn't too concerned about streetability with this truck, but the nice thing about keeping the axle ratios high is that it keeps cruising RPM down on the highway with the NP435 since there is no over drive. You can use 1st with the NP435 to take off to compensate for the 4.10s in the axles so that you can actually use the four speeds on the street

I wonder if the 4.0 would be bogged down in 4th on the street.

 

['84 Bronco II]

I wonder if the 4.0 would be bogged down in 4th on the street.

Having 4.10s with no overdrive would be equivalent to running 5.38s with a .76 overdrive, which is a pretty typical overdrive ratio (the stock 5 speed that would have come behind the 4.0L in that Ranger had a .79 overdrive). The 4.0L is a pretty torquey engine, so it probably isn't terrible.

 

[Hyde]

I wonder if the 4.0 would be bogged down in 4th on the street.

I'm sure it wouldn't be too happy, the only time this truck sees the street is between trails.

I'm going to grab a junkyard 1356 and mock it up with my extra 205, if I can't make it work I'm out maybe $40. I'm using factory engine mounts and a factory style trans mount for a 97 f350.

Between all the mounting options on the 205 I think I can figure something out that would just carry the weight while still allowing it to pivot with the trans mount, or run the same mount I'm using for the trans if I can tuck it high enough