np203/203 doubler what do I need

1983Bronco

1983Bronco

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On your mom in Winston Salem NC
I meant to say 205/203 doubler, sorry! I have an sm465/205 combo and I want to go with a doubler, so I know I need part of an np203, but do I need the whole np203, which case goes first the 205 or 203, just looking to get the parts together. Thanks

Brad
 
I think you have to use an NP205 from behind a TH400. If you get a 205 that was originally mated to a SM465 or TH350, then you have to change the input, and the input bearing or something like that. I beleive the front part of the 205 case has to be machined for the larger input bearing. I might be wrong on all that, it has been a long time since I did all the research, and I never built one.
 
drkelly said:
I think you have to use an NP205 from behind a TH400. If you get a 205 that was originally mated to a SM465 or TH350, then you have to change the input, and the input bearing or something like that. I beleive the front part of the 205 case has to be machined for the larger input bearing. I might be wrong on all that, it has been a long time since I did all the research, and I never built one.
Click to expand...


Dk is right.

I'd get one from Jeds.
 
I got mine from Jeds also. I'd def recommend them.

Transmission -> NP203 rangebox -> Doubler -> NP205

Ideally, you want to find a 203 from a truck that had your transmission. When you order your doubler, they will cut down and re-spline your shaft to match whichever NP205 you have.

They will also weld the adapter clocked to your request and mill the surface flat.

I'll look for a pic of my doubler setup....
 
If you look at the picture you'll see my setup... ignore all the cable shifters and brackets.
There is a long shaft that goes from the NP203 range box and extends into the chain drive section of the NP203. You remove this shaft and send it to Jeds (or buy their hardened shaft) and they machine it down to fit into the input on your NP205.


So all you really need to do is source an NP203 from behind an SM465 or use an adapter.
FYI I think that mid 70's K30's had an option for a 465/203.


I found this information on Off Road Design's website:
GM SM465 4 speed Manual Transmission:
If you have an SM465 transmission there are 3 ways to mate it to the NP203.
1: Use a factory configuration. GM mated the NP203 to the SM465 in 1973-1975 using the 10 spline output in the 465, a 10 spline female input in the NP203 and a 4.25" adapter housing between the two. This configuration was used in a wide range of GM trucks but is somewhat rare. Problems are the 10 spline connection tends to wear in the long term and it's difficult to find. Positives would be the short length and the ability to use the common 10 spline output in the transmission.
2: Use a SM465 that was originally mated to an NP208 transfer case. This 465 will have a 32 spline output shaft with a 8 3/8" adapter housing. You'll use a NP203 gearbox with a 32 spline input gear and the face of the 203 drilled and tapped with the GM round bolt pattern to match up to the factory 208 adapter housing. This works very well if you have the available length in the vehicle since the parts are commonly available and the 32 spline connection is very strong and durable.
3. Use the factory SM465 to NP203 adapter housing with ORD's new 32 spline SM465 output shaft and a 32 spline input gear in the NP203. This allows the shortest overall length with the highest strength, most durable spline connection.
 

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TheGriz said:
If you look at the picture you'll see my setup... ignore all the cable shifters and brackets.
There is a long shaft that goes from the NP203 range box and extends into the chain drive section of the NP203. You remove this shaft and send it to Jeds (or buy their hardened shaft) and they machine it down to fit into the input on your NP205.
So all you really need to do is source an NP203 from behind an SM465 or use an adapter.
FYI I think that mid 70's K30's had an option for a 465/203.
I found this information on Off Road Design's website:
GM SM465 4 speed Manual Transmission:
If you have an SM465 transmission there are 3 ways to mate it to the NP203.
1: Use a factory configuration. GM mated the NP203 to the SM465 in 1973-1975 using the 10 spline output in the 465, a 10 spline female input in the NP203 and a 4.25" adapter housing between the two. This configuration was used in a wide range of GM trucks but is somewhat rare. Problems are the 10 spline connection tends to wear in the long term and it's difficult to find. Positives would be the short length and the ability to use the common 10 spline output in the transmission.
2: Use a SM465 that was originally mated to an NP208 transfer case. This 465 will have a 32 spline output shaft with a 8 3/8" adapter housing. You'll use a NP203 gearbox with a 32 spline input gear and the face of the 203 drilled and tapped with the GM round bolt pattern to match up to the factory 208 adapter housing. This works very well if you have the available length in the vehicle since the parts are commonly available and the 32 spline connection is very strong and durable.
3. Use the factory SM465 to NP203 adapter housing with ORD's new 32 spline SM465 output shaft and a 32 spline input gear in the NP203. This allows the shortest overall length with the highest strength, most durable spline connection.
Click to expand...


Damn thats nice!
 
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