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  • Writer's pictureHunter Dias

Transfer Case Tear Down

Updated: May 17, 2021

At Transfer Case Solutions we take the tear down process seriously. We don't fly through a tear down. Every part is methodically taken out, fully inspected, and insured to be up to OEM spec be fore reusing.

After inspection, the internal parts are organized and await the cleaning process. Cleaning process utilizes Parts Wash Tank with industrial leading bio safe formula to inhibit rust while cleaning. Ultrasonic Wash with specially formulated solution. Media Blast Cabinet with strong abrasive that's safe on all metals. And Electrolysis tank for deep cleaning of rust on all surfaces, even unreachable surfaces.

It's very important to tear down your transfer case for full inspection. Especially if you pick it up from a 3rd party and do not know the history. Even junkyard transfer cases aren't without fault. You can see here the metal shavings built up inside the transfer case.

The magnet helped but when you get this much metal, a magnet can only do so much.

When bad things happen due to neglect, your transfer case will self-destruct. Adding to the metal shavings will be chunks of metal from broken internal pieces.

There is the possibility of water getting inside your transfer case. We all know water and oil do not mix. Given enough heat and pressure you can get what is know as emulsification. This mean the water molecules are broken down into teeny-tiny droplets that can remain suspended in the oil. Having the water suspended in the oil takes away from the protection characteristics of oil. This in turn hurts the parts inside your transfer case adding wear on parts because they are not protected by oil. This lowers the life expectancy of your transfer case.

When the case with the water and oil emulsified sits for a long time the water will separate back out. Water being heavier than oil, it will sit down inside your transfer case. With enough water your metals parts, which were once coated with a layer of oil, will rust. Last thing you want to do is install a rusted transfer case with rust all over. Bad for contact surfaces, bad for bearings, reduces the life of your transfer case.

The "bullet proof" NP205 is only as bullet proof as it's owner. Here you can see the shift fork pad on the right is worn down.

Where as here the front output shaft yoke's oil seal surface has a groove worn into it. If your transfer case leaks from the yoke seals, doesn't always mean you need new seals. Hard parts wear out too. You can see a wear mark to the right of the groove where the hard oil seal was pressed down further as a band aid, in hopes of stopping the leaking oil.

The tear down process is very important, and not a step to gloss over. It will tell you the life story of the transfer case. Knowing the life story of the transfer case will determine how the transfer case will be rebuilt. If it's rebuildable.

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