Ok so I have a 78 f150 4x4 with a 351m c6 trans dana 44 diffs and np205 transfer case.

I tried to shift in to 4x4 the other day and shifted it into 4H. I then shifted back to neutral and it wouldnt shift out(the transfer case), I eventually tried 2nd gear(on the column) and it shifted out. So today I put it in 4L and now no matter where I shift(on the column) or what I do it seems stuck in place.

Any ideas whats going on maybe im just operating 4 wheel drive wrong.....I dont know whats up but i had surgery not too long ago, so if I can know what to look for or do before getting under it would be great.

 

I have the exact same lay out on my truck. The 205 was a grenade proof tranfer case, but it wasnt the easiest to engage or disengage. When you have everything locked up in 4 wheel drive, get the wheels straight creep forward. Now with the wheels still straight, back up a few feet then slide the trans shifter to nuetral. Try taking it out of 4 low. I had the same problem on mine, and the best remedy was to flush out the ATF in the transfer case a few times and to engage and disengage it few times a month.

 

x2 on what nine inch said, you may just have a case of "driveline wrap". Not to insult you but if you are new to these older 4x4s, the part time setups like this should not be operated on pavement, the driveline will bind.

 

yep triple the above, they are impossible to shift if you have driven them locked in and got em in a bind. straighten em up and reverse then drive forward.

 

Ill be the first to admit I dont know everything, however ive used it alot off road or in the snow....however never on dry pavement.

Considering too that its not been used in over a year It was infact bound up. So I put it in reverse about 15 feet and it wouldnt shift out, then put it in drive and crept forward 15 feet and then it did shift out and is fine now.

Im going to throw some new gear oil or trans fluid in it and flush it a couple times, i just never realized how bad it was to drive on dry pavement in 4x4. Wont make that mistake again.

However while on this quest to replace the trans fluid ive heard a billion and one different types of fluid to use. This truck will spend more time on the pavement in the coming years, so im guessing trans fluid and not gear oil is the way to go. However what trans fluid is kinda a mystery as ive heard atf 4 mercon, dexmerc? etc etc and then gear oils rangine from a 85w-140w with various front numbers on that. So ill look alittle more in here and tomorrow when i open it up ill see what was in it be it trans fluid or gear oil and go from there.

 

The factory service manuals (1976) call for sae 50wt motor oil for all transfer cases and manual transmissions in the light trucks above 0 degrees. 75-80w is what was suggested here to me as I couldnt find any straight 50 when I was servicing mine.

 

Mine had just regular dexron. Not sure if thats what it calls for but after 40k of ownership the tranfercase shifts fine.

 

Use 50w motor oil or 90w gear oil (they're the same viscosity) i'd recommend the gear oil.

X5 what the others have said, stay off dry pavement in 4x4

If you do bind up the t-case again, driving in reverse 10-15 feet is usually enough to disengage the gears, if not, pull forward 10-15 feet and repeat, the t-case will eventually unload.

 

changing the lube will not make it shift any easier. Its part of long term maintenance but don't expect much of a change. The NP205 is gear to gear and its very strong but it takes a strong handshake even when its healthy and lubed. And if you bind it up, no synthetic lube or anything else is gonna free it up until you release the bind.

 

Agreed but if you have no idea when or if its ever been changed, its not a bad idea to change it with the proper lube