When you are in 4-wheel drive the front axle is locked so both wheeld drive regardless of traction available, if you drive in 4 wheel drive on dry pavement and try to turn, the wheels will still try to go the same speed and slip on the pavement causing a clunking sound.
It being an American vehicle
There are several things that can cause your 1995 Chevrolet Blazer to shake when accelerating. Bad spark plugs and spark plug wires can cause the vehicle to shake. Tuning up the engine may eliminate the problem.
Any number of things could cause your vehicle to surge. You need to take your vehicle to a tune-up shop and have it diagnosed.
Check Antifreeze level..make sure there are no leaks under the vehicle.
A bad universal joint is one possibility.
It depends on when you hear the noise, but it likely a joint in the front wheel drive unit.
It would all depend on the condition of the vehicle as with all vehicles
What year the vehicle is would be helpful and what engine you have.
I would suggest purchasing a shop manual for that vehicle to do that job.
check coolant level may be low or thermostat may be faulty
Worn trans or diff parts. If it gets worse, have it looked at.
The simplest thing to check would be the universal joints on your drive shaft. See if you have any play in any of those universals. The springs in the center of the clutch disk could also be out and cause a clunking. MGB's also have thrust washers in the differential that wear out and cause a clunk in the differential.