Major clunk coming out of 4 wheel drive on the highway

Rear ujoint may be bad causing vibration when under load from transferring. Also could just be loose or bad carrier bearing.

I would check the spark plugs and wires or coil packs. Sounds like the ignition system is arcing.

I have a 2003 GMC it has two buttons to use 4 wheel drive as most all do with push button controls...One is for standard highway driving with 4 wheel drive the other is for 4 wheel drive a low speeds for off road driving and conditions that need low speed less spin driving..not designed for highway use..and must be stopped to engage where 4 speed highway can be shifted on the go..hope this answers your question..good luck..

driving in 4wd on hard surfaces produces what is known as torque wind up as the wheels cannot slip so the variations of distance going around corners , dips in the road etc place considerable strain on the transmission , transfer case , drive lines and diffs
that is why it is difficult to get out of 4wd unless you drive with 2 wheels on a grass verge to relieve that torque wind up
as for the noise check wheel bearings and the cv ("U") joint at that wheel as there appears a proble where the dog teeth in the hub are not engaging properly or are jumping out of engagement

1) Take car to non dealer shops willing to give FREE opinion

2) Not likely you have a shock in Driver Front wheel, more likely a strut. Not likely strut needs to be replaced, but strut has a STRUT MOUNT (3 bolts of which can be seen when opening your hood) below this it is connected to STRUT BEARING which below it connects to UPPER SEAT OF STRUT or SPRING INSULATOR, that if loose will rattle. Usually, shops will not tighten, because to tighten is same labor as replace the parts. (Since you already dropped $1000 on ToyotaDealer, ask them to tighten FOR FREE since rattle is still there.)

3) There is a part called a "link," connects strut to stablizer bar, that if bushings are bad will rattle.
4) If stabilizer bar bushing(s) bad, will rattle early on but eventually clunking
5) Bad ball joint or tie rod can rattle as well

Never permit any shop to do expensive work on your car w/o first getting a second opinion somewhere else first. Do not tell second shop that you are there for a second opinion.

Shaking steering wheel at highway speed, no braking
1) Bad tire in front, bad tires in front, verify inflation of tires
2) Wheel alignment may be out
3) Front suspension parts (mentioned several above)

Highway speed to suddenly braking shakes steering wheel
1) Front brake rotors need to be inspected for warping
2) Test calipers on empty road at 40 mph, going straight on very LEVEL ROAD, hit brake pedal SOMEWHAT hard while barely touching steering wheel. If car jerks to one side, instead of braking straight on, you may have a caliper, ABS, or brake fluid pressure regulator off.
3) If brake rotors are warped, may as well replace front brake pads at same moment. Use ceramic.
4) When you drive on VERY LEVEL road on highway, steering wheel must be centered, let go lightly of steering wheel. Did car stay in middle of lane? No? Get a 4-wheel alignment.

You have one or more loose wheels. You are in danger of loosing the wheel and hurting your truck, yourself and me. Don't drive the thing any further than you have to. What you are hearing is the wheel(s) chucking on the lug nuts. Let it go long enough and it will shear the studs and the wheel will fall off. If all the wheels check O.K. check the drive shaft for a bad universal but I'm convinced it is a wheel. Good Luck.

Unless your climbing big hills, I'd leave it in 4 high, for normal roads. If you happen to get stuck, better to shift to low, to get out, then when back on highway, or main roads use high. Remember, 4 wheel drive might get you out of the snow or whatever better, but it will slide sideways, and stop the same as 2 wheel drive, so don't think you can go faster than those ahead of you with 2 wheel drive, if roads are bad. Sorry, I know, you know better, but I see more 4 wheel drives in the ditches around here in Canada, than 2 wheel drives, in fact I've seen 2 beside each other in same ditch, as I slowed down for ice patch, and drove past them. Yes I did check to make sure they were o.k. though.

That noise sounds to me like a Ball Joint problem. I would check to see if you have fittings to grease the front suspention.

Good luck, Allen

That is up to your preference in my opinion. 4 wheel may give you a little more traction, but it can also lead you into a false sense of security. If heavy snow, and you need to get through it, you can only go as fast as the guy ahead of you anyway right? Up here in Ontario Canada, I passed by many a 4 wheel drive in the ditch, because they assumed they would have a better chance on icy roads than me, with 2 wheel drive. Remember this, no matter what you decide, you may be able to go a little faster in 4 wheel, compared to 2 wheel, but when you have to hit the brakes, or go into a spin, 2 wheel or 4 wheel drive, your not going to be able to stop it any faster. Your going to use more gas in 4 wheel too. Yes there will be times when you need to use it, but like I said, when it goes sideways or you have to lock up the brakes, because you were pushing the envelope too much,? At least with 2 wheel, you feel the back end break loose, to warn you how slippery it is, and you may not feel that soon enough, with 4 wheel. Just my opinion, but maybe some 4 wheelers have a different opinion. It's just like the experts from the skid school said up here about mandatory snow tires being talked about. If putting snow tires on your car is going to make you drive a little faster, your defeating the purpose.

Will your 'friend' take it back? 1 prob, likely a vaccum leak at the intake. 2 prob, at 'stopping'?? Brake pads. Stopped, good question. 3 prob, either the plastic cover or the horn pin under the steering wheel. 4 prob, This sounds like the exhaust 02 sensor is acting up. 5 prob, shock bushings or rubbers mounts on sway bar. Or the top bearing on a strut. 6 prob, Fixing the past probs 'may' solve this? 7 prob, Just live with this! You have enough on you plate already! Frankster016