Dana 20 T-Case Differences

Today I was all ready and excited to swap in my replacement Dana 20 transfer case when I ran into a slight problem.
In the picture, I circled the recessed areas that are not present on my replacement t-case. In the bigger circle, the tranny has two pins that stick out, hence the recessed region on that part of the connecting face. The smaller circle is less recessed and just has holes, whereas mine is not recessed at all in that area.
What's the deal? Different manufacturing year? I'm planning on having the case machined to make some room for those pins, but is this a good idea? I'm not really sure what tranny I have- the engine is a 360 if that narrows it down ...
TIA
FredS

 

Also, this may be a dumb question but I can't for the life of me figure out where the temperature sending unit screw into my my engine- any help? TIA

 

Those recessed areas look like the same ones from my Dana 18 but I probably am wrong.

 

I ran into the same problem with my d20's. THe closest i can figure is that the one without the recesses was from a j truck or more likley a commando with an automatic. I ended up getting the relief machined into the case. The machinist just stuffed a rag into the hole and had at it. He used the gasket as a template. I installed a magnetic drain plug, and changed the oil after 5 miles, to make sure there were no shavings. Other than that you dont really have alot of options.

The one in the smaller circle didnt seem to do anything, and there was no corresponding feature on the trans, so i didnt worry about it.

 

What's wrong with the transfer case you have now?

You could take the guts out of the new case and put them into the old case, but that's not much different from fixing what you have.

There are several variations of the 20 ... look here for a table. Make sure the gears in the new case are compatible with your output gear.

20s are common and cheap - personally I wouldn't mess with the case you have. I'd look for another one.

 

I agree with Tim that you could just exchange the parts from 1 case to the other. I'm woundering if the difference ibn the cases is for the T15. Some transmissionn/D20's share the oil resivour and are essentially open between the transfercase and the transmission. I will attempt to attach a photo of my case it shows the areas you are refering to

 

LarryD- I think you are correct with the T15- I think that is the tranny I have- I snapped a few more pictures to show a little better what I'm looking at-
Pic1 is why I can't exactly exchange parts . . . (not sure how that happened)
Pic2 is the t-case that I took off . . .
Pic3 is the t-case I planned on putting on. . .

 

I don't know why you couldn't do as DrDamtelll did , hog out space with an angle grinder or die grinder.

 

To shed a little more light on this issue, Eric at Novak offered the following:

"What you're seeing are differences between the earlier Dana 20 cases and the later ones.

The one with more recesses in it is earlier. I would guess that they did this to hold oil for the input bearing to draw from. Later versions, they cast it solid and for what reasons, I am not sure. I have never really seen any performance or longevity differences. It may be that they were attempting to strengthen the flange as some technicians would use the bolts to pull the gearboxes together, breaking the bottom ear of the flange off."

So to reiterate, earlier cases have the recessed regions, and later cases have the solid face. When the switch occured I'm not sure. My jeep is a 74 so I guess sometime after that . . .

 

Its alot harder than that. Its about 1/4" deep, and there is the gasket sealing surface to deal with. I was originally thinking of doing that , but everybody I talked to said i should just bite the bullet and take it to a machinist. I'm glad i did, and it only cost me $20. Die grinder might work, but that's alot of grinding time!