I just picked up a Dana 61 rear axle with 3.31:1 gears that I am going to put under my highboy with a NP205 transfer case. I'm running 7.50R16 tires.

I think I need an 8 tooth drive gear and 17 tooth driven gear. I have read that the gears for a NP205 are the same as for a NP435 4 speed. Is this true?

If it is, I think I need a C8OZ 17285-B drive gear and C3DZ 17271-B driven gear.

Anybody want to double check my work? I'm not the best with the Ford parts book...

 

what! you want an accurate speedometer? what kind of foul sorcery do you speak of?


all kidding aside i would like answers on how to change the speedo gears also where does one find them? how hard is it to swap them? how does one figure out which gear they need? ect ect ect

 

They are color coded as to the number of teeth they have. That determines the speed.

 

how does one figure out which ones are needed/ where does on find them?

 

Speedometer Gear Calculator and Charts - TCI® Auto

The driven gears are a piece of cake to find. I just need someone to verify that C8OZ 17285-B is the correct drive gear for the NP205.

 

Anybody? I can't find any mention of this gear being used for a NP205 and I can't find an 8 tooth gear for a NP205 at all...

 

If you have an ebay account try to message the seller for both of these. They state in there auctions you can message them for help with gears....

Eotz 17285 B or C8OZ 17285 B Ford Speedometer Drive Gear 8 Teeth | eBay

D3TZ 17285 A NP205 NP208 Ford Speedometer Drive Gear 7 Teeth | eBay

 

The 435, 205, and c6 use the same speedo cable gear. You should be fine as long as it looks the same and has the right teeth. If you look on the end of the gear the tooth count is also molded into them. Real tiny font but it should be there.

 

What about the speedo drive gear in the t-case? Is it NP205 only or is it the same as other trannys?

 

That I am not sure about. They appear the same but I have never had the need to swap one out.

 

LMC shows two different gears for c6 vs np205. The big difference is the reverse rotation of the gear. Mine keeps chewing up the gear in the output shaft so I'm guessing maybe I have the wrong gear??? I'm confused.

<a href="http://s881.photobucket.com/user/mvosu/media/F250Crew/70%20crew%20Highboy/826E7834-6FCA-4E74-803F-819FE73C6C91_zpso9dyzhot.png.html" target="_blank"><img src="http://i881.photobucket.com/albums/ac20/mvosu/F250Crew/70%20crew%20Highboy/826E7834-6FCA-4E74-803F-819FE73C6C91_zpso9dyzhot.png" border="0" alt=" photo 826E7834-6FCA-4E74-803F-819FE73C6C91_zpso9dyzhot.png"/></a>

 

Transfer case makes no difference. Speedo gears (DRIVE on output shaft; DRIVEN at end of cable) based on trans type/tire size/rear axle ratio.

But, if the trans is a C6, the DRIVE gear is made as part of the output shaft, cannot be replaced by itself.

Upper pic: Scroll down to 3.31-1 applications / Lower pic: 17285 specs.