NP205 Transfercase Servicing

I just bought a 79 Bronco with the NP205 transfercase, I am wanting to drain out the old fluid and put in new. What weight oil do I need to use, how much does it hold, where do I drain it, and where do I put the oil in at. These is the first 4wheel drive I have owned.

Man you've got me struggling to remember. I honestly don't recall if the NP205 has a drain plug, but I think it only had the generic drain-n-fill plug leaving you to **** out most of it with a turkey baster with some vacuum hose fitted onto the end of it. I *DO* remember that I used a straight-weight 90 gear-oil with it and using synthetic oil would NOT be a waste of your time or cash. You now own what has GOT to be the hands-down *best* transfew case ever made so appreciate it & take care of it. If you're interested you can always use the engine vacuum & a peanut butter jar to make a sort of vacuum sucker for the gear oil, if you're interested let me know 7 I'll explain it but otherwise a turkey baster & vacuum hose work just fine to get out most of the oil and if you buy a couple gallons of it then you can easily swap it out twice and be SURE that you're running new & uncontaminated fluid. Just look for the 1/2" square plug on the case, they're easy to spot and that's what you want. If there are two and one's low while the other is hign then, well, the low one is your drain & the high one is your fill. If you only find one then it will be high and it will be a drain/fill port. I can post scans of an exploded view if you need them but they do *not* show drain/fill plugs (I looked) but they ARE usefull for rebuilds or refreshenings.

Do you recommend straight 90 weight gear oil as being the best thing to use? Also is there a particular brand of gear oil that may be better than another? If you have time post the exploded scan, that would help out a lot. Correct me if Im wrong, but isnt the NP205 all gear driven instead of having a chain?

Yes, the 205 is gear driven, that & the steel case are probablythe two things that make it THE #1 trnsfer case out there. You'll *never* get a better Xfer case unless you shell out upwards of $2K for an Atlas. The 205 is King, simple as that. I'll post the entire section of the Ford service manual on it if you'd like (and yes that includes the exploded view as well as detailed service & rebuild instructions). Yes, just a straight 90wt gear oil but again, I would really use a synthetic since it's available. Synthetics make a *real* difference today and it will help with not only shifting it but the lubrication in general will be superior. Use a natural oil if that's all that's handy or affordable but if you *can* swing it then I would strongly suggest the synthetic.

How many quarts does that bad boy hold? I was also wondering if it causes excessive wear if you leave the hubs locked in but have the transfercase in 2H. That way when the roads are nasty and you get in a hard spot you dont have to get out and lock in the hubs you can just put in in 4H or 4L. I dont mean I would run it like this all the time, just in winter weather.

To be honest I've never really measured just how much it hold. I always bought 5 or 6 of those 2qt bottles of gear oil and then drained as much as I could and then filled it until it ran out of the fill plug. Seeing as it was gear oil I never really changed it all that often, especially since I always ran the vent line way up into the rear fenderwell and way abouve any high-water that I got into. Maybe two or three times in the life of any one truck.

As for the hubs, no man, go for it. I would *routinely* lock my hubs in October and leave them that way until March or April. Open them up once a year and do your maintenance on them and then forget about them. It maybe costs you 3 or 4 miles per *tankfull* of gas to keep them locked but not much more. It's far and away the easiest way to go, you only need to engage the Xfer case lever if/when you need 4WD and knowing that the hubs are already locked makes life a LOT easier. I wouldn't hesitate to run my truck that way throughout the winter. Just make sure that you open the hubs and do your maintenance at LEAST once a season.

Thank you for your posts you have been very helpful. I had a little bit of bad news today. I have been busy so I didnt have time to go pick up my Bronco where I bought at until today. It doesent have a choke on it, I have no idea what the other owner did to it, but anywho I poured a little gas in the carb and she would fire right up then die, poor a little more she would fire up then die. After doin this a few times I figured I check the gas in the tank, and probably as you guessed it, absolutely nothing was in it. Soooooo being today was New Years all the little local town gas stations were closed, so I gotta go back this weekend. I felt so stupid for not bringing a bigger gas can with more gas. The guy told me today while I was there that it had all brand-new u-joints that made me feel better, just somethin else I wont have to worry about for years.