Dana?
Dana?
- Thread starter kickitandholdit
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thats a good one havent ever thought how they came up with the numbers
IOPort51
NOT the voice of reason Jeep-CJ.com
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4.2 W/MC2100 carb, 4.0 head W/3 angle valves,SS Header,TFI ignition with MSB-6 offroad module,CS144 140 amp RPS alternator with remote regulator T-150,d-20,Dana 44 with OX lock and disk brakes. D-30 with Spartin locker,
skyjacker 2.5 lift?nitro shocks,31" BFG A/T off road.8000 lb Warn winch, original owner.=^)
2006 Toyota Tacoma
the day of the month of the engineers wifes birthday. drive line parts are like stars and asteroids, if you discover it you get to name it. The NP408 Transfer Case , Natalie Peterson (the engineer, john Peterson's wife) April 8th. They didn't mention the year for obvious reasons. 
Don't step in the Bull
!!
Don't step in the Bull
!!
Kane
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the day of the month of the engineers wifes birthday. drive line parts are like stars and asteroids, if you discover it you get to name it. The NP408 Transfer Case , Natalie Peterson (the engineer, john Peterson's wife) April 8th. They didn't mention the year for obvious reasons.
Don't step in the Bull
WTF!!!! How did you know that? That is the craziest explaination I have heard. Pretty cool though.
IOPort51
NOT the voice of reason Jeep-CJ.com
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4.2 W/MC2100 carb, 4.0 head W/3 angle valves,SS Header,TFI ignition with MSB-6 offroad module,CS144 140 amp RPS alternator with remote regulator T-150,d-20,Dana 44 with OX lock and disk brakes. D-30 with Spartin locker,
skyjacker 2.5 lift?nitro shocks,31" BFG A/T off road.8000 lb Warn winch, original owner.=^)
2006 Toyota Tacoma
I'm sorry guys, a couple of beers after a long day and the imp of the perverse got the better of me. Do you think this would make a good urban legend? 
Old Dog
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I'm sorry guys, a couple of beers after a long day and the imp of the perverse got the better of me. Do you think this would make a good urban legend?
Thats go'na be my story from now on.
But for the real scoop check this out. CJOffroad.com - General Information
kickitandholdit
Old Time Jeeper
wow thats so funny. that was pretty good. i could see that being true though
i could see that being true though
BajaEdition
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hey both of those are not true
the real reason they got named
is much more simple.
The size of the clock spring is taken i ratio with the gear count of the spyder gears divided by the circumference of the inner race bearings. this in fact is then multiplied by pi and divided by aspect ratio of the front pumpkindcover. So fo a Dana 30 it is cs+sgc/cirbxd1cklength/pi{ASSpucker}=D number
the real reason they got named
is much more simple.
The size of the clock spring is taken i ratio with the gear count of the spyder gears divided by the circumference of the inner race bearings. this in fact is then multiplied by pi and divided by aspect ratio of the front pumpkindcover. So fo a Dana 30 it is cs+sgc/cirbxd1cklength/pi{ASSpucker}=D number
BusaDave9
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I checked out that link and it saidThats go'na be my story from now on.
But for the real scoop check this out. CJOffroad.com - General Information
"The old model numbers were calculated as follows:
Model = (pitch diameter X 100 X face width)/24
The pitch diameter and face width is of the ring gear."
I don't get it. How can they take into account the face width of the ring gear? The ring gear is a different width for each gear ratio. BajaEdition's "simple" explanation is a little more believable but I like the thing about the day of the month of the engineers wifes birthday best. Actually the NP in NP208 stands for New Process Gear, a division of Magna Powertrain, the makers of the NP208 (and other drive train components).
As for the number in the model. I am guessing but I don't think the number has any relevance. Like the Pontiac 6000 and the BMW 325 I think the manufacturer just makes up a number. Newer or larger models then get bigger numbers.
BusaDave9
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Face width is across the tooth surface. I got it now.
BusaDave9
Always Off-Roading Jeeper
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With the axles the larger the number the bigger the ring gear.
With the transfer cases the bigger the number the later they were released.
The Dana 20 has a 2 to 1 gear ratio for low.
The Dana 300 has a 2.6 to 1 gear ratio.
There are other differences. For example if you have a Dana 20 then there is a gear that sticks out of the Transmission . This gear sticks into the TCase when they are bolted together.
If you have a Dana 300 then there is an output shaft that sticks out the tranny and into the TCase.
The older Dana 18 TCase has an offset rear output.
Here are the Dana Tcases found in Jeeps:
18
20
300
kickitandholdit
Old Time Jeeper
good info 
CJ
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I'm gonna have to kick a buncha asses... Great thread!