I know there have been a lot of posts about vibrations but none that I found sound exactly what I'm experiencing. I bought 94 4Runner a few months ago at an auction w/o realizing the kind of work it needed. I have already replaced the engine. I used the 4wd for the first time yesterday and noticed that there is a vibration in the front (I think) when 4wd is engaged. It feels like riding on big knobby tires. When I push the clutch in, it stops. I know nothing about the 4wd system so I would appreciate any theories you have to help me track it down. It's a 3.slow w/ manual trannie, auto hubs.

One more stupid question. I had an 88 (1st gen) 4Runner years ago that had auto-locking hubs. I remember having to disengage 4wd and back up to unlock the hubs. Looking through the 94 owners manual, it doesn't say anything about that. Is it not necessary on 2nd gens?

 

My womans 95 runner stays in 4 wheel drive until you back up a little bit, but I never had that problem with my 92 before I removed all the add stuff.
As far as the vibrations go, I would start by looking for a bent drive shaft in the front. Sometimes there's a bearing the goes out on the front diff housing on the driver's side usually, right where the cv/half shaft bolts to the casing. If you have a little time the best way to check that is to unbolt the half shaft from the differential and just see if you can wiggle that flange around that the shaft would bolt to. You may want to try and see if the drive shaft shakes or wiggles around at all, could be a bad u-joint or cv. Good luck and I hope you find your vibration, they can be annoying.
One last thing, next time you have the front of your runner in the air, try moving the tires back and forth and watch your tie-rods to see if there is any excessive movement.

 

Do your self a faver and chec the U-Joints. I have the same rig, and this is what my problem was. Don't just go under the rig to see if the driveshaft moves back and forth with play. When I did this, it had no play at all. I took it to a shop to see if they could find the problem. The 1st thing they did was put the rig up on the lift. Once the rig wass off the ground, it had alot of play in the driveshaft. Also in the frunt of the driveshaft, they was able to push up and down on the driveshaft. I would bet that this is your proble. Mine had a bad vibration in 2W drive. It was not drivable at all in 4WD.

 

How bad are ther vibes ???
The reason I ask is , if the vibes are only slight , it could be normal .
The "driving on knobby tires" that you described sounds like normal 4wd vibes to me
I have had four 4Runners and 5 Toyota trucks over the years .........and every one of them has had a slight vibration in 4wd .
For that matter , both my atv's have a bit of vibes in 4wd too .

I have had the front drive shafts out of my trucks in the past , and I have noticed that the yoke ears are slightly out of phase the splines are just out enough that if you pull the shaft apart to align the ears , you end up out of phase in the other direction , there is no in between .
Find someone else with a Toyota 4wd , and compare the vibes to yours ....I bet theres will be the same as yours ......

If you use the 4wd in the dirt and rough stuff like you should , you wont feel the vibes

Hope my driveshaft theory makes sense to you , if not maybe someone that knows what I am talking about can explain it a little better .

 

The vibration is not that bad. I suppose it could be normal but my 88 runner didn't vibrate in 4wd. It really does feel like knobby tires as opposed to a shake.

This was supposed to be my dream truck but every time I turn around I find something else wrong with it, so I guess I'm just a little suspicious. I will never buy another vehicle w/o driving it.