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NP208 Speedo Drive Gear

rebelgregory

rebelgregory

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Does anyone know what speedo drive gear was originally in an '88 NP 208. I'm going to overhaul the t-case soon and wanted to correct speedo at the same time.

Were there different gear or all the same? How many teeth?
 
Any idea on the odds of one being in there already? Most of what I've read tells me its either a 15 or 18 tooth. Eventually, I'm gonna have to go look, I know.

By the way, I appreciate the help. I know your input on these matters is highly regarded by the brotherhood.
 
Good chance yours will be an 18 considering the original gears. Always happy to share, I learn a lot more from the folks on this site than I contribute
 
In most cases the stock civilian gear is the blue 18t. The gray 15t did come on the M1009's and they also had a over speed ratio drive mounted on the transfer. You will most likely need one of those too. I just went through this on my rebuild. Luckily the gray 15t drive gear is available, the blue 18t is not.
 
Massboy said:
....and they also had a over speed ratio drive mounted on the transfer.
Click to expand...

you lost me on that one. Can you explain? Are you talking about one of those external Speedo correction boxes?

EDIT: The online calculators state I will be good with a 15/40 gear setup. Figured on 34.5" tires for size variances and tire wear. Hopefully shouldn't need an external gearbox.
 
Yes, one of these. The M1009 w/31's, 3.08's, and the 15t gear needed this over speed box. It was stock on them. With the 32's, 3.08's, 18t gear (transfer case from a civilian donor), 45t driven gear, I still needed this box to get the correct reading.

IMG-20140313-00483.jpg
 
rebelgregory said:
you lost me on that one. Can you explain? Are you talking about one of those external Speedo correction boxes?

EDIT: The online calculators state I will be good with a 15/40 gear setup. Figured on 34.5" tires for size variances and tire wear. Hopefully shouldn't need an external gearbox.
Click to expand...

Your gear calculation is dead on. Be sure the aluminum housing that holds the gear is for the 40-45 tooth gears and not the 34-39 series, there is a difference in offset.
 
Whelp...go figure, I need all new stuff. My driven gear housing is for the 34-39 tooth gears which tells me the stock drive gear HAS to be an 18 tooth. Got a new housing, and 15/40 gears on ebay for about $50 so hopefully it'll all get sorted. Thanks again for the help.
 
I just went through this with mine, 35s 4.10 gears and np241. Spoke with multiple experts and the only way to get mine correct was a ratio adapter box. No combination of gears would correct mine. The box was only like $60

6d878d8a31961ffe13a841cab5793884.jpg
 
I considered the range box, but it's not my first choice. I checked with a couple different calculators and they both stated the 15/40 combo would work with the 208 and my setup. Maybe something different about the 241? Limited drive gear options possibly?
 
I ran your numbers through my calculations and came up with the same 15x40 combo, provided your speedometer is ok you should be spot on.
 
rebelgregory said:
I considered the range box, but it's not my first choice. I checked with a couple different calculators and they both stated the 15/40 combo would work with the 208 and my setup. Maybe something different about the 241? Limited drive gear options possibly?
Click to expand...
Yea from what I found the 241only had a gear drive speedo for one year (89). So there is a limited selection for drive and driven gears. Just my luck [emoji16]
 
Did you shine a light in the opening to see what color the driven gear is? I thought there was another tooth count option from a Dodge or something that could be made to work with a spacer. The spacer can be made from the old driven gear. Sorry I can't provide any links right now, but might be worth some research.
 
I remember reading something about that. I haven't looked inside mine. Once I realized that I had the 34-39 tooth Speedo housing, it was mathematically impossible for me to have a stock 15 tooth drive gear, so I just went ahead and bought everything. I will post what gear I find in there when I get it open. Might help someone in the future.
 
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