Grinding The Case

Most Dana 20 cases will need grinding to clear the Rear Sliding Gear (TL20-E) of the Teralow gearset.  Teralow suggests some will not need grinding.  If it does need grinding, the question is how much.  To check clearance I attached the rear output shaft assembly to back of case and attempted to put the Rear Sliding Gear on.  For my case, it wouldn't go on so grinding was necessary.  Below are the examples of where Teralow suggests you will have to grind.

Dana 20 case before grinding.	Dana 20 case after grinding.

Note: Most Dana 20s require grinding. Even if your case doesn't seem to need grinding, be sure to check the Slide gear through positions with shaft and sliding output gear in place to make sure case clearance is complete.

After some initial grinding I was able to get the gear into the case for a test fit.  I rolled the gear and marked contact areas with a black sharpie.

I had contact in several places.  It took several rounds of marking and grinding to get it right.

For better grinding, I resorted to my favorite tool, the angle grinder.  I took the shield off and was able to get it into the case to where the grinding was necessary.

This is where most of the grinding was necessary.

I also found that it might be possible that the gear could make contact when fully engage the other way so I trimmed a very small amount of material off the other side.  CAREFUL!  There isn't much material there.  I didn't want to risk a hole in the case.

I was making final checks on clearances.  When I was happy that the gear cleared, I was ready to clean it up and start the assembly process.

Cleaning and inspection

I washed all transfer case components except the Rear Output Housing assembly.  With the Rear Output Housing, I was careful not to get it dirty because I wasn't taking it apart.  Only the removal of the gasket on the Rear Output Housing was necessary. 

The rest of the transfer case including the housing and re-used parts were washed in hot water and Simple Green.   I also cleaned the gasket material from all gasket surfaces and dried all components with compressed air.

At this time I inspect all parts that were to be re-used including bearings, thrust washers and gears for excessive wear, pitting, and scoring. If any part is damaged or worn, it must be replaced.

Painting Parts

If you're like me and you live in an area where rain, snow, ice and road salt are constantly assaulting your vehicles, then you'll know why I like to paint everything.  I hate rust.  So after the parts were cleaned of the grease and dirt, I gave everything a coat of gloss black.  I like to use Rustoleum.  I've been using it for years and it seems to hold up pretty well to the elements.

Everything else was cleaned well and painted.  Don't paint the machined gasket surfaces.  Either tape them up or spray carefully and wipe off over spray.  Since I wasn't disassembling the rear output housing, I cleaned the surface and kept the gears and bearings dry and clean.

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Torque Specifications:

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