Dana 300 oil

[4xbrian]

I'm about to install a d300 behind an ax-15 in a CJ. So, what is a good oil for the tcase, and is there anything I should know regarding the oil when clocking it flat or nearly flat?

[TSwiss]

80W-90.

I put a sight hose on mine so I knew how high the oil level was, but you may need to decrease the amount of oil you have in it the flatter you clock it. Alot of guys have had alot of oil blow out th breather hose by adding the stock amount of oil after clocking it flat.

I like to have the rear output bearing bottom ball covered, or just touching, depending on how much clock you have. You could use a bent wire in the hole to see how much oil is in.

[Loftis61]

Typically, my rule of thumb is, anything with an aluminum case = Auto tranny fluid.

Anything with a cast iron case - 80/90

The sight tube is also a handy addition, as well as looking cool

I will also add that you might want to extend your breather hose up if you are going to be hitting water/mud of any kind.

[4xbrian]

Noted for the breather.

Regarding the sight tube, is it a drill and tap deal, or use one of the existing bolt holes? Have you seen a need for a catch tank for blowby?

Another question: Is there a needed difference in front d/s length for a case clocked flat vs. in stock config? Obviously mathematically yes, but in practice? My brother is putting my junk together for me while im out of state, but he's not too familiar with offroad vehicles and his time is at a premium. So I'm thinking of having him go the easier route and using the stock config, then clocking it later. But I dont want to have the shaft cut too short for a stock setup then need a longer one later. Opinions?

[TSwiss]

For the sight tube, its drill and tap. I did 1/4" NPT thread and a couple of 90 degree push connect fittings.

The driveshaft does end up longer, but that will depend on how long it is now and how much angle is on it. A quick way to see if it will work is throw it on clocked where you want it, and measure the driveshaft length from T-case yoke to pinion yoke. Then take your old driveshaft, and extend it and compress it by hand, and measure the extended and compressed lengths. If your lift isn't ridiculously high and your driveshaft is long (maybe over 30") then you probably need around 1" to 1.5" of extension and compression max from resting height.

This is just a quick figure, you may need more than that depending on your setup.

[Bubba_Jeep]

Originally Posted by TSwiss

For the sight tube, its drill and tap. I did 1/4" NPT thread and a couple of 90 degree push connect fittings.

Excuse the off-topic question--but what tubing did you use for the sight-tube?

[TSwiss]

Originally Posted by 4xbrian

Have you seen a need for a catch tank for blowby?

With the fill level where I have it, I don't need a catch tank for blow by.

Originally Posted by Bubba_Jeep

Excuse the off-topic question--but what tubing did you use for the sight-tube?

PVC clear 5/16" tubing. The size depends on your fittings, mine needed 5/16".