vibration in 4x4

[1$Chuck]

My truck has started shacking when its locked in 4x4. If the front hubs are locked and the transfercase is in 2wd, I get some vibration, but not bad. Also, if the hubs are unlocked and I shift the transfercase to 4 hi, I get a little vibration but not too bad... but if the front hubs are locked in and I shift the transfercase in 4hi, it shakes pretty bad at anything over 28mph. This is definitely a new occurance, I to be able to run at 45 or 50 with pretty minimal vibration in 4x4.

I don't know the whole history of this truck, but the front driveshaft has lables on it that lead me to believe it was replaced at some point. I can't find any U joint that is visibly bad. I got under the truck and tried to shake the front driveshaft. Its has some movement but I wouldn't call it excessive. The front output shaft from the transfer case has some wiggle to it as well, but not real bad. I spun the shaft around by hand and could feel no binding or hear any noise. Also I couldn't feel anything hot after driving about 15 miles in 4x4. Any suggestions? Also I've noticed that its become hard to get shifted out of 4x4 recently. I sometimes have to back up to get it to shift into 2wd. I didn't have to do that before.

[Sutter1stgen]

Check the front drive shaft and the actual axle U-joint for excessive wear.

[sloppy2nds000]

you should pull your front drive shaft and inspect the u-joints for any wear or looseness. it only takes about 10 minutes to get out even if its really stuck in there. there are 3 joints in the front shaft. the 2 off the transfer case can be hard to spot play in and nearly impossible to grease via the grease fittings.
if you have to replace one of the paired joints replace them both and really you would benefit from replacing all three in this case.
the front shaft sees less use and far less winter road slime so it doesnt wear out as often as the rear drive shaft. so it you replace all three you wont likely have to revisit that drive shaft for quite some time.
also its a good idea to lock your hubs every now and then in the summer to warm the grease and move it around in the front axle if you never use 4x4 in the summer. this can in my opinion, keep the front joints serviceable longer. you dont have to engage the tc to do this.

[dazedandconfused]

Check your fluids in the transfer case to. I just helped a Buddy with a similar problem and the transfer case aas empty. We bandaided it for now.

[1$Chuck]

I just pulled the driveshaft. It was pretty hard to extend and retract, the grease was very cold and stiff. The front ujoint was apparently dry because I of course forgot to hold onto the caps that go to the axle side and they fell off and needle bearings went everywhere. The two on the transfer case side seamed to move OK. The shaft coming out of the transfer case has more play in it than I think it should have. I checked the fluid it was a little low but no where near out. I topped it off with more 90w. I leaks so I've added fluid to it pretty regularly but I remember the first time I checked it it was pretty much empty. I think It this point I'll either rebuild or replace the front shaft and try to limp into warmer weather.

[dazedandconfused]

First I've heard of using 90w in a transfer case I've always used at.

[CumminsPower59]

NP205's use conventional gear lube. It's everything else that runs thin stuff.

[dazedandconfused]

All the Ford and Chevy 205's I've had have used atf.

[Tacoclaw]

AFAIK all 205's use gear lube. It makes sense since they're the only ones with actual gears in them anymore. Any of the newer, aluminum housing chain drives always call for ATF.

I couldn't keep fluid in mine if I used anything thinner than gear oil.

[ellis93]

All the Ford and Chevy 205's I've had have used atf.

Yep and use a p!ssy little pump to lube the trash inside

[CumminsPower59]

I'm pretty sure NP205's are splash lubricated.

[ellis93]

Might be......it all runs together for me,the ones I've downed have had pumps that were driven off the output shaft. They're mostly newer stuff.....they may even be different animals and I am all confused about the whole thing

[1$Chuck]

I recall reading about 205's when I first got mine and differant manufacture's used differant weight oils but New Process basically specified that it needed lube in a range of like 15w up to 90w. Don't quote me on that, but I was looking at the time because mine leaks and I wanted to run heavier oil.

[CumminsPower59]

Basically all the aluminum cased, chain drive units used ATF, had lube pumps driven off the output shaft, like Ellis said. The NP203 was a cast iron case, chain driven unit that used 10w30. The NP 205 was really the only gear driven, splash lubricated transfer case, and used traditional gear lube.

[sloppy2nds000]

im not sure what the t-case in my truck is but i had it on the ground sunday, and back in the truck yesterday. it was damn heavy and awkward. like almost stupid heavy, barely weighed less than the tranny and that was stupid heavy but far less awkward. and it called for gear lube when we looked it up at the parts store. 2 quarts of up to 90w.

2$chuck, keep up on that grease man, and be sure to grease that rear pair of joints. they kinda suck to remove and replace. you may have to use a small grinder or rotory file to clean so me of the casting burr off to get the grease gun in there. shes a tight one. dont forget to check your front axles now too.