T-Case Questions (She's Alive)

[72Highboy]

Hey hows it going everybody been almost 2 years since I've been on, being stationed up in Fort. Carson, and being in the army makes it hard to work on my truck. Plus my truck being down in Texas makes it even more difficult.

Well on to the topic I finally got the 72 F100 up and running after the sprindle finally giving way and breaking. (Mother was driving it for a week and half all that was holding it was the 6 hex keys, and the locking ring for the 4x4 hub) . Well luck be having it, in Colorado Springs UP&P I found a bump 4x4 (sadly destroyed after getting parts off it) that had a Dana 21 and complete Dana 44 front to take the spindles and hub assembly. Second round trip to UP&P I found a Highboy that I snagged the divorced NP205. Well being back home on leave finally gave me the time to fix her up took me awhile to remember how the put the sprinde back toghter along with buying a new set of Warn Premium locking hubs since the passenger side was destroyed when the spindle broke. Little hick-up and disapointment to figure out that the power steering pump finally went out after 34 years of normal size tires and 6 years of turning 38's. Next up on the operating table was the extion housing and Dana 21. All bolted up and running smooth now wanting to go fully test it out but have some questions.

1: With the guys that have ran Dana 21 or still do what oil do you use and how much?
(Im guessing to the side fill hole, since I have a fill hole ontop I can pour through.)
2: Is there any way to keep it from poping out of 4wd when using it.
(The little hill I tested to see if the hubs locked and if the T-Case actually worked seemed to make it pop out of 4wd.)

Any answers to my questions is greatly appreciated and ideas or thoughts. Glad to be back home working and playing around with my bump.

[Doug Comer]

I have one truck with the 21. I have never had an issue with it popping out of gear. Maybe the linkage is out of adjustment?

Doug

[CrypticRacer13]

Have some one run the stick while you look at the linkage from underneth.

[averagef250]

If it's properly engaged and it pops out you have worn parts inside.

Transmitting power holds it in gear. Just like a transmission. Try pulling a stickshift trans out of gear under full throttle.

[72Highboy]

None of that I knew, Ill have to try that. What type of oil you guys us and how much?

[harrysnyder]

Gear oil

[greentruck]

I use 80w90 gear oil, if i remember correctly it took 2.5-3 quarts. but you are right just fill it till it spills out the top side fill port. if you end up swapping to the np205, i would like to see a thread on how it goes if you have the time to take pictures and type it out.