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Lets talk doublers

wetoolowdingbangow

wetoolowdingbangow

1/2 ton status
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Ok well I just came up on a np203 and Np205 recently and im looking for some guidance.

After seeing bmxbryant9s 465/203/205 with 5.38s work, I knew that was the direction I wanted to head so im slowly but surely aquiring stuff. im hoping to throw a doubler in the truck this winter. That will allow me to rebuild both boxes and do some r&d for my adapter. I'll be machining the adapter between the boxes myself and buying the intermediate shaft from ORD.

There a lot of knowledge out there about the 203 205 set up, including people doing home brew adapters. It was brought up in my build thread that I should look into 241 205 doublers. I know I read through a bit of Chris's (ord) 241/205 home brew and it looked pretty good. Not sure if its still in use.

So heres a couple questions I have...

Should I bother with the 241 if I already have a 203? My understanding is that it would be lighter and id get an extra gear out it. I dont really care about weight when its down that low. If anything itll keep me from tipping haha.

The next issue at hand is input and output shafts. My 205 is the figure 8, 10 spline in 32 out....if I am correct I should replace the 10 spline input with a 32 right?

My np203 is 27 spline input.... I should swap that to 32 spline because 10 splines isnt as strong and there are 32 spline sm465s out there?
 
You don't really have anything you need.

The 27 spline NP203 is super common, and not what you need.

The 10 spline NP205 can be made to work.

You don't have an SM465 yet.

Martin
 
Yeah with what you currently have I would pursue the 241/205 setup. The extra gear is completely worth it IMO.

I wheel with just a 241 right now and its a very useful ratio. The 2:1 would be good for something where you need wheel speed and 5.3:1 along with a sm465 you'll have a ratio for anything.
 
To convert the 10 spl. 205 to 32 spline input, you will need to bore out the case FYI since the 32 spline uses a bigger bearing. 10 spl and 27spl use the smaller bearing. Since you are having the intermediate shaft made, you could always use a 31 spl Ford input in the 205, just in case you were able to find one for cheaper. Plus the ford 205 will have a 32 spline front output.

Just throwing that info out in case you didn't already know
 
82355 said:
You don't really have anything you need.

The 27 spline NP203 is super common, and not what you need.

The 10 spline NP205 can be made to work.

You don't have an SM465 yet.

Martin
Click to expand...

Haha maybe not what i need but i know others want it.

The way i figure with the 465 is that ill most likely only be able to find it in the 10 spline fashion. Ill continue to search for the 32 spline version. I just found a 465 mated to a 205 for $160. Might be able to flip that.

MTBLAZER89 said:
Yeah with what you currently have I would pursue the 241/205 setup. The extra gear is completely worth it IMO.

I wheel with just a 241 right now and its a very useful ratio. The 2:1 would be good for something where you need wheel speed and 5.3:1 along with a sm465 you'll have a ratio for anything.
Click to expand...

So with the 241 i could run:
lo-lo
lo-hi
hi-hi
hi-lo

Not sure if i have that right. It would also be 5.3:1 compared to 203/205s 3.76:1? I want to be able to disable the front drive shaft from spinning while in 2wd if possible. I guess thats what twin sticking the 205 will get me?

muddermilitia said:
To convert the 10 spl. 205 to 32 spline input, you will need to bore out the case FYI since the 32 spline uses a bigger bearing. 10 spl and 27spl use the smaller bearing. Since you are having the intermediate shaft made, you could always use a 31 spl Ford input in the 205, just in case you were able to find one for cheaper. Plus the ford 205 will have a 32 spline front output.

Just throwing that info out in case you didn't already know
Click to expand...

Boring out the case is no big deal. I think i follow you on the ford shaft.
 
203/205 = 3.96:1 both low .

and ord has short shaft 32 spline outputs if I recall to keep whole combo real short .

http://offroaddesign.com/catalog/sm465shortshaft.htm

205 is a part time case already so in 2wd front shaft is not engaged .

203 was full time case like that .

twin stick shifter on stock 205 gets you 2wd low range only .

twin stick shifter and modified rails gets you front wheel drive high/low option and rear neutral .
 
sweetk30 said:
203/205 = 3.96:1 both low .

and ord has short shaft 32 spline outputs if I recall to keep whole combo real short .

http://offroaddesign.com/catalog/sm465shortshaft.htm

205 is a part time case already so in 2wd front shaft is not engaged .

203 was full time case like that .

twin stick shifter on stock 205 gets you 2wd low range only .

twin stick shifter and modified rails gets you front wheel drive high/low option and rear neutral .
Click to expand...

Good info thanks! If i went with a 241 i supposed id have to find a passenger drop?

Im still not sure which direction to head. Ive got CAD files to make the 203 adapter in my hand but nothing for the 241. It appears to be easier...

http://coloradok5.com/forums/showthread.php?t=247978
 
I have the 32 spline SM465/NP203/NP205 combo under a Blazer. I have a double cardan joint in my rear driveshaft. The length doesn't bother me too much.

Martin
 
Why a 465. I wheeled with a guy with a 465 /203 / 205. He hated it. But we do pretty technical crawling. I can go from slow technical crawling to spinning the tires anywhere. He often had to back off of stuff because the 465 in first was too low to really get them spinning. In backing off he would often get off line.

That being said I realize there are preferences and if a 465 is what you want then go for it.

I would do the 241 / 205 cause it's easier. The adaptor between the 2 cases is very much the easy part. Especially if you don't mind it being steel.

208 came being 465 and the 241 is very similar so it would be much easier to mate them.

It would be very easy for you to bore out the 205 and get a 32 spline input. 241 205 with a 465 wins because there are more different ratios available.

So with a 465 I would do a 241 / 205 cause it's easier better ratios.
 
blazinzuk said:
Why a 465. I wheeled with a guy with a 465 /203 / 205. He hated it. But we do pretty technical crawling. I can go from slow technical crawling to spinning the tires anywhere. He often had to back off of stuff because the 465 in first was too low to really get them spinning. In backing off he would often get off line.

That being said I realize there are preferences and if a 465 is what you want then go for it.

I would do the 241 / 205 cause it's easier. The adaptor between the 2 cases is very much the easy part. Especially if you don't mind it being steel.

208 came being 465 and the 241 is very similar so it would be much easier to mate them.

It would be very easy for you to bore out the 205 and get a 32 spline input. 241 205 with a 465 wins because there are more different ratios available.

So with a 465 I would do a 241 / 205 cause it's easier better ratios.
Click to expand...

Im just not a fan of autos anymore. The more autos i have the less i like them. To me its worth not having to worry about the over heating and strength. I know my 700r4 is pretty stout but nowhere near what a 465 is. The other major benefit is with the steep hills ive encountered out wheeling, the manuals have far greater ability to use engine braking to keep you from relying solely on the brakes.

skunked said:
damn thread has me rethinking things now :doah:
Click to expand...

If youre doing an auto id say the 203 is good for that. There is such a thing as too low with auto trannies. I think i ran the numbers and 203-205 is in the sweet spot for an auto. Plus i might have the perfect 203 for you...

GWeakland620 said:
Pshhhh, that's what this entire website does:haha:
Click to expand...

Yeah pretty much. Im not completely sold on the 241 yet. I just remember watching bmxbryant motor along great and when it came to faster sections he was far in front of me.
 
wetoolowdingbangow said:
I just remember watching bmxbryant motor along great and when it came to faster sections he was far in front of me.
Click to expand...

That's one of the nice part about the doubler. It is super simple to switch the range box back and forth between high and low.

Martin
 
82355 said:
I have the 32 spline SM465/NP203/NP205 combo under a Blazer. I have a double cardan joint in my rear driveshaft. The length doesn't bother me too much.

Martin
Click to expand...

Same for me but I also did a 3" stretch in the rear.
 
wetoolowdingbangow said:
Im just not a fan of autos anymore. The more autos i have the less i like them. To me its worth not having to worry about the over heating and strength. I know my 700r4 is pretty stout but nowhere near what a 465 is. The other major benefit is with the steep hills ive encountered out wheeling, the manuals have far greater ability to use engine braking to keep you from relying solely on the brakes.
Click to expand...

These are the same reasons I went with an SM465 instead of an auto . . . plus there is a huge factor of nostalgia.

Now, one major disadvantage to a manual offroad is that you need both feet for go so you often can't apply brake and gas at the same time unless you get a hand throttle like I am installing.
 
Yah just different expirence. I have seen lots of guys lose clutches.

But man I do love the 700s first gear. Can't be beat. You certainly have to know how to build em though. 465 is simple for sure

I do know as bad as our frame flex is I would do a modified linkage if mechanical or a hydro if at all possible.

I would still suggest the 241/205. Just cause it would be easier to find the bits
 
82355 said:
That's one of the nice part about the doubler. It is super simple to switch the range box back and forth between high and low.

Martin
Click to expand...

Right. Can you shift while moving? My 208 sucks balls. I have to come to a stop, throw it in neutral and shift.

truck-oholic said:
Same for me but I also did a 3" stretch in the rear.
Click to expand...

As in moved the axle back?

truck-oholic said:
These are the same reasons I went with an SM465 instead of an auto . . . plus there is a huge factor of nostalgia.

Now, one major disadvantage to a manual offroad is that you need both feet for go so you often can't apply brake and gas at the same time unless you get a hand throttle like I am installing.
Click to expand...

Ah yes. When bmxbryant was on 1st-lo-lo he could start the truck with the clutch out and it would stay alive. It was slow enough that you wouldnt need brakes, so far the technical stuff thats what im aiming for.




One thing that may create some problems is the guy (D&D machine) is no longer around, who made the in between shaft for the 241/205. Im not sure if anything is available now that hes off the grid.
 
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