Here are the shift rails. The interlock resides inside the aluminum housing. Also note tha
The Dana 300 has exceptional strength for its size. Worthy believes that a stock Dana 300 can easily handle power ratings up to 350 horsepower and 350 lb-ft of torque, while Novak says they regularly see them handling big-block power and deep compound gearing without failure. Novak also reminds us that the Dana 300 was used successfully in the Jeep J-4000 1-ton trucks. Breakage usually occurs because of shock loads to the drivetrain from an aggressive driver, a worn intermediate shaft, or worn bearings.
If there are any drawbacks to the Dana 300, it would have to be the standard 2.0:1 low-range gear ratio and the fact that the centered rear output shaft does not allow it to be clocked for improved ground clearance and driveline angles the way a Dana 18 can be with its offset output. Also, the Dana 300 gears are unbalanced, and Novak says that while it is rare, breakage could occur because the helical front seat can produce significant side loads against the case.
With the endplate removed from the front output shaft, the bearing is visible. The endplat
Mel Wade at Off Road Evolution in Fullerton, California, had an old Dana 300 in his shop and offered it up as the sacrificial lamb for this story so that we could get a better look at its internals. We headed down to Fullerton, where we plucked an old Dana 300 out of the junkpile and let it die a hero.
Also be sure to check out the excellent history, parts, and rebuild guides available at www.novak-adapt.com.
Model 300 in Popular Production Vehicles
1969-'73 Blazers (some)
1962-'79 Fullsize J-series
1967-'73 C101 and C104 Commando
1972-'79 CJ-5, CJ-6, and CJ-7
With the case flipped over and the inspection cover removed, you have a better idea of how
Dana 300 Quick Hits
Similar to Jeep, but used a left-side front output shaft and/or a lower 2.46:1 (or 2.34:1) low range.
Not as common as the NP203 or NP205 and only used with three speed manual transmission.
Had twin sticks from the factory up to '69.
Avoid the problematic remote style "J"-shift versions.
Visible in this photo are the input gear's "bull teeth." A sliding output gear acts as the
It's hard to tell in this photo if the intermediate gear is being removed, but the entire
After completely gutting the case, we welded all of the various components together to giv
1829 W. Commonwealth Avenue
648 W. 200 N. Suite 1