speedo driven gear in transfer case same as T400 driven gear?

[ronniebomb]

Hey Y'all!
I'm pretty well versed in the automoblile rear wheel drive world as far as figuring out what driven gear I need and where to find it.
But, I need to know if the gear in my 203 transfer case is the same as a standard T400 driven gear?

1978 GMC K25 454/T400 203 3.73 gears

So, assuming I have the 15 tooth drive gear (that would be in a T400 output shaft) I'd need a 34 tooth driven gear because I have 33's on now.

Is this correct?.....or is there a different style of gears in the transfer case???????

I already ordered the 34 tooth T400 gear...........so I'm hoping I assumed correctly!.,...lol!

Thanks ahead of time!

 

[ronniebomb]

Upon further research, it looks like the system is different...........so..........

Can anyone help me locate information on the np203 transfer case speedometer gear system?

I see some different spline count plastic gears on ebay, so I'm guessing that the output shaft has the drive gear cut on it?......
So I would need to know what that spline count is......
Then I could figure out what plastic gear I would need..........

Help please!

 

[Craig 85]

Several of my squares with 203's ran an adapter similar to the one below. There are several companies that offer them.

You must be registered for see images

 

[idahovette]

The driven gear in my 203 is a metal gear 31 tooth I believe and there are a few others, at least a 30 tooth and a 32 tooth. I am looking for a 32 tooth now.

 

[ronniebomb]

Several of my squares with 203's ran an adapter similar to the one below. There are several companies that offer them.

You must be registered for see images

This is probably the way I'll have to go, I happened to have one that's a 1:1.300 ratio that I installed Friday. It over compensated....... I was 4 mph slow @30, with the 1.300 I'm 5 mph fast now.
So I'm looking for a 1:1.160 adaptor. I have an email to speedometercablesUSA out of Denver. I hope they can hook me up with what I need.

idahovette.......this seems to verify that there aren't too many choices for driven gears on the 203's.

 

[mmerlinn]

Hey Y'all!
I'm pretty well versed in the automoblile rear wheel drive world as far as figuring out what driven gear I need and where to find it.
But, I need to know if the gear in my 203 transfer case is the same as a standard T400 driven gear?

1978 GMC K25 454/T400 203 3.73 gears

So, assuming I have the 15 tooth drive gear (that would be in a T400 output shaft) I'd need a 34 tooth driven gear because I have 33's on now.

Is this correct?.....or is there a different style of gears in the transfer case???????

I already ordered the 34 tooth T400 gear...........so I'm hoping I assumed correctly!.,...lol!

Thanks ahead of time!

NP203 driven speedo gears are all steel on an integral steel shaft.

List of known gears here >>>

https://mmerlinn.com/catalog/lil_wane111/xn_203/xn2034m0.htm#d