Truck shakes when front hubs are locked up????

[sikn3s]

So yesterday I went 4wheeling I noticed a potential problem and figured i'd get sum input. When I would engage the truck into hi4 or low4, the entire truck would shake VERY NOTICEABLY. It would get worse the faster I'd go. Then when i'd get off the gas the entire front end would shake until the truck came to a halt. But with the front hubs not locked, none of this would happen. ONLY WHEN THE FRONT HUBS ARE LOCKED does this happen. I can put the truck in 4hi or 4low (for the gearing) and nothing abnormal will happen. I ran it shaking like this the whole day like this and it really killed part of the fun.

My best explanation on to how the shaking is speed dependent (not made to scale lol)

ACCELERATION:
MPH: ......0..........10..........20..........30
SHAKING: x x x xxxxxXXXXXXXXXetc...

DEACCELERATION:
MPH: .....30..........20..........10..........0
SHAKING: XXXXXXXXXxxxxx x ...x .....x

Sorry about the crude table but you get the picture... SO any1 have any idea wtf is wrong with my front end. Oh keep in mind that this is an sas 86 toyota, stock gears and open diffs front and back.

[elripster]

My first thought is front drive shaft u-joints. See if they have play and make sure they have been greased.

Frank

[MiniSimp]

Driveshaft or bent axles

[slosurfer]

If you don't have a locker on the front and you have only one hub locked for this test, won't it only spin the axle on the side without the hub locked as that will be the side with the least resistance? It will just be free spinning that axle in the hub, although I guess this will still let you know if the noise is made on one side or the other.

[blake85]

ya i would check our u joints, that's what it sounds like. i am having the same problem with mine. but in 2hi. it sucks, i'm going to redo mine tomorrow.

[yotaman91]

First of all you dont have u joints, you have birfields. And second, you don't bend toyota axles, you break them. My guess is the the tang on one of you lock washers is busted. Jack up you front end and try to jiggle each tire individually, tear into whichever side moves and replace it (lock washer (get a chilton)).

[Cheese]

He does have u-joints in his driveshaft, not birfields.

Toy axle housings bend a lot. Stock shafts and Stockfields break a lot.

Is the shaking a new thing? If so, what was changed?

Are you just asking if some front end vibe is common with hubs locked in 2 or 4 wheel drive, the answer is yes.

Please explain this tang idea. I do not know what one is and I fail to see how one of 6 per side would do anything like what is partially described.