Franken-commando???

So, earlier I introduced my 73 Bullnose Commando in the VIN forum...
Spent the last few days poking around and investigating, have determined the driveline has been replaced.

She does have the AMC 304 V8, but the rest appears to be different.
Tremec T176 4-speed transmission
Dana 300 transfer case
AMC 20 rear axle

and, I think a Dana 30 front axle. I'd like some help in confirming....
The cover appears to be consistent with either a Dana 27 or a 30. There is a 30 cast into the top of the diff housing. The metal tag appears to say "3.31 43 13" and "5363734" in two rows (though somebody painted the tag...).

There appears to be a port for a breather vent in housing, just right of top dead center if looking at differential cover, though the vent is plugged with a piece of wood painted black....(INSPECT THOSE USED VEHICLES!!!).

 

As a 73 Commando, She should have a Dana 27, the 30 would be a change from factory.

please expand on open vs closed knuckles, how do I tell by inspection?

 

Found the knuckle type, open knuckles.

 

Front axle should be 535xxxx, a model 30 in the '73 Commando. Open knuckle is a 30. I don't have a book that overs '73 but they are out there.

43 13 is 43/13 = 3.307 or 3.31 ratio. This is reasonable for a Commando. Make sure the rear matches the front before you engage 4WD.

A Corporate 20 rear (M20) is a reasonable swap for a Commando, since the spring pads line up. There is nothing major to prevent an '80-up drivetrain from a CJ to be swapped in to a Commando. Jeep never offered the T-176/D300/M20 combo in the Commando, but it was offered in the '80-up CJs.

 

No, every '72-73 Commando came from the factory with an open knuckle Dana 30 front axle.

 

Thank you for the help.

Another question, the Dana 300 (or typically all transfer cases) have a 1:1 output ratio between the front and rear driveshafts, correct? I’m going to jack up and count tire to driveshaft rotations, that would suck for there to be a reduction in the transfer case between the two outputs.

 

5363734 tag would be for a 1982 and later CJ, 3:31 ratio FYI.

 

If you are looking to check gear ratio's, do your self a favor and drop the covers and do a tooth count. This will give you a chance to inspect the ring and pinion, carrier for damage, and refill the pumpkins with fresh oil.

 

Your D300 has a high range ratio of 1:1 and a low range of 2.62:1. You can't have any "mixed" ratios; either 1:1 high range for both front and rear outputs, or 2.62:1 in low range for both front and rear outputs
The transfer case has two shift rails. One controls high or low range, and the other controls rear only (2WD), or both front and rear outputs (4WD).
-Donny

 

My 70 Commando has a 27 front axle.

 

70 1/2 and 71 Commandos had the D27 set up for Saginaw steering. 72 and 73 D30 open knuckle.

 

After a busy day, I have confirmed both axles have a 3.07 ratio. Both have a 43 ring, and a 14 pinion

The front D30 now has a tapped brass vent routed by the battery box.

Tomorrow will be installing tail lights and working other electrical issues.