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Rebuilding the Dana 20 Transfer Case

Rebuilding the Dana 20 Transfer Case
While inspecting the Dana 20 it is obvious that the bottom cover has seen some better days. Have any of you replaced your bottom cover? If so which one did you use?

I see that NOVAK has a cover. It looks nice, but it should look nice at the selling price. While searching a Dana 20 cover for a Ford Bronco popped up. The price is better, but I really don't know if the Ford Dana 20 uses the same bottom cover. Looking for replacement suggestions.
 
Lumpy, thanks. I can get a stock replacement part here locally. One of those tough as nails after market affairs would do the trick.
 
Figured you could-Just good to have a 'back-up' sometimes.
This is when that SOB 'Murphy' likes to work overtime......:laugh:
LG
 
When at Willys Works for my springs and ball bearings, even Rob said that I 've had a bad run on poppet springs, There was some conversation on heavy duty Transfer Case bottom covers. Rob dove into his bottom cover pile and came up with a military version that is twice as thick as the stock over. It looks like they took two covers pressed together & welded. There is nothing flimsy or cheap about it. My front diff. cover is similar.
 
:banana::dbanana::banana:
LG
 
Busa and others that have done it - The 20 is being reassembled, it definitely needs grinding. What would be the right tool, it says to use a Die Grinder. Unfortunately I don't have one of those. I do have a dremel but that seems like it would be tedious.
 
I have use a right angle die grinder(air-powered)and a Dremel for close in, when we did the gears in my D/300.
How much has to come out?
LG
 
Which tool did you use? I'd like to use a flap wheel rather than a grind stone.

How much to remove? At this point it looks like a mile, but that is the way it is with case iron. I'm expecting the usual amount on the bottom cover bolt edge. It looks like there will be a need for grinding some of the top of the case. It will take some grinding to really know.

I'm looking for a nice clean grind not something that looks like a Neanderthal performed the job.

It was interesting to find that the case needed clearance grinding for the stock gears, not the part next to the bottom cover. The other side.
 
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Come to think of it I do have one of those. It's buried on a shelf with Air tools on it. The thing never impressed me much. Fast but weak and gutless. Time for a second chance.

I've moved a lot of metal with a flap wheel on my angle grinder. Far faster than using an actual grinding wheel.
 
When I rebuilt my Dana 20 and installed the TeraLow kit, it required a bit of grinding/fitting. I used an electric die grinder - sort of a Dremel on steroids - and a 2" or so stone. There was a lot of test fitting/turning to get it clearanced. But it does fit.

Now.... Here's another issue I had to deal with: Drain plug clearance. If you are using the stock drain pan, and the original plug is screwed too far in, it will contact the big gear. Took me a while to figure out what was causing the problem. Solution: different drain plug, or many wraps of teflon tape around the original to keep it from screwing in too far. Or get a deeper aftermarket pan.
 
Good information
 
Thanks for the memory 'shake'.:D I too ran into the drain plug concern with my D/300, 4:1 install.
Found that a STD steel pipe plug, gave me the clearance needed. I did still grind about 1 1/2-2 threads off the end of the plug.
LG
 
To speed the grinding along, you can use carbide burs that are used to port cylinder heads. A lot faster than stones, just make sure you get the ones for cast iron and not aluminum. Summit has a pretty good selection. A bit pricey, but I have worn down many stones for what I can do with one carbide burr. Besides, we all like spending other peoples money!:D
https://www.summitracing.com/search...=Powerhouse Products Porting Bits, Individual
 
:)

Harbor Freight on the die grinder........under $20 bucks I buy them all the time if they fail within 90 days they give me a new one.......Use the carbide or HSS burrs.....they cut fast.

:D:D:D:D
 
First, got some stones from H-F for the air tool. Worked Okay. Found that if carefully used a 3" angle grinder grinding wheel can get some of the work done in a hurry. Okay so why isn't the job done? I'm having trouble distinguishing the front of the case from the back, especially when the case is upside down and I'm working at off angles. The case was ground beautifully. Testing showed that the gear still bound up horribly. Then I realized that I ground the wrong side/the front of the case. EEEEERRRRRRRrrrrrrrrrrr! No harm done, Just some more time on the grinder/die grinder. The air grinder works well enough, but you've got to keep the RPMs up.

It looks like lots of places touch in my case, but until the main area is fitted it is really hard to tell.
 
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Go'n through my notes when I did the D/300 switch over. I found a note that sez to clearance the gear to where you can slide a business card without much drag between the gear and case.
LG
 
Yep doing that. Found clearance where it looked like there wasn't any. Hopefully the grinding will wrap up tonight, The rest of the case should be easy. That is if the shifting fork and the drain plug are clear.
 
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