Dana 20 Vs Dana 300

I measured the input to output (horizontal offset) for a dana 18/20 with it mounted in the standard clocked position.
In other words the horizontal distance from input to output is 7-5/8".

Anyone happen to know or have a Dana 300 to measure its horizontal offset ?

 

I see where the factory clock angle is 23 degrees. Maybe that helps.

 

Thanks Walt, at least I got a reply Ha Ha !
I don't have a Dana 300 and I'm trying to determine if the D-300 has less or more offset than a D18 / 20.

 

After reading this, I was curious myself. I just went down to the shop with an angle finder to measure the 300 vs an 18, which should be the same as a 20 (I'm not crawling under the 3b to measure the 20 - it's raining).

Conclusion: I can't tell. It's so hard to find a baseline of 0* on a t-case that is on a bench, I just couldn't get an accurate reading.

Wasn't the 300 roughly an upgrade on the 20, but with low range helical gears and lower ratio? I doubt they would have redesigned the angle, but who knows.

In researching, I found the distance between the input and the front output is identical, and as Walt stated, the 300 is 23* drop. All I could find on the 20 is that it was "near 20* drop" which could be 23*.

 

So, does that mean for a swap from a D20 to a D300 there would be minimal fab work, if at all?

 

In a word, no.
They have completely different faces (300 is round, 20 is Texas), and the 300's bull gear is part of the t-case. It's essentially an enclosed, self-sufficient unit.

 

Well here's whats going on (partly in my head) Ha Ha !
I measured the exact input offset of the various common narrow track Jeep axles.
In other words how far the input is offset relative to vehicle centerline.
Those axles include D25 D27, D30, D44 tapered, D44 flanged offset carrier and D44 flanged centered carrier.
All axle inputs are offset a little differenly excepting that D25 and D27 are identicle to one another.
And most amazingly the center flanged D44 input is actually offset 1" right of Jeep centerline

Then I measured the side offset (not drop) of the D18.
And YES the D18 and D20 offsets are identical.
Like I said a D18/20 is offset 7-5/8" horizontal to the passenger side.
Upon observing the propeller shaft alignment I can readily see what the various offset numbers indicate.
The propeller shaft is never perfectly square to any of the various axles.

Furthermore I determined that for narrow track jeeps with standard axles the transfer case need not be offset that far to the side.
About 1" less transfer case offset would be ideal for most narrow track axles.
So I was simply wondering if Dana 300 offset could be better in terms propeller shaft aligment.

Of course these facts are also relative to engine offest from true centerline. and transfer case positioning left to right.

I was thinking to buy a 1980 Scout Dana 300 because are the only D-300 case with the Texas pattern.
But it will be of no advantage to me if the horizontal side offset is the same as a D-20.

Make sense ?

 

If talking about a scout 300, it will bolt up, but I'm not sure about the bull gear. I read that all 300s have a 23 tooth input spline, but I'm not sure if that included the bull gear on scouts.

Scout 300 on left with a bull gear from an automatic, and Jeep 300 on right.

 

47v6 ,I took out my 20 and bolted up a texas 300 no problems .

 

Interesting. What bull gear? From the 20 or 300?

 

the 300 has it's own gear ...

 

Right, but that had the same spline count as the 20?

 

I have very roughly 2" of difference ,
inside of boxed frame to cl of texas300 is 12" and about 14 " from frame to yoke

 

the 20 bull wont work on the 300

 

it's been on my jeep for 10 yrs now I don't remember

 

I won't be doing this maybe ever, but I have read that the D300 is a very good transfer case and one that might be worthwhile to go to IF one were to use a centered rear differential.

 

D20 is still good and D-300 is probably overkill unless you have really a big engine with big clutch and super low transmission.

 

The pinion in a flanged Dana 44 axle from a DJ is however actually centered. Which is why I like to use them in my v6, 400t, 20 builds as it takes away one of the angles from the driveline equation. I believe the CJ version in an intermediate was offset just to keep both axle shafts the same length?

 

So your saying that the DJ has 2 different lengths of axle shafts ?
The CJ Dana 44 pinion is offset exactly 1" to the right and yes the axles shafts are interchangable.
If the engine is offset say 1-1/2 " to the left then the propeller shaft alignment is .... Well it's kinda WEIRD !

 

Yes a DJ centered rear has about a 23 and 27 inch axle instead of the matched 25 inch CJ axles. They are also sometimes much cheaper as people don't place much value in a DJ. I have actually been given complete DJs before.