Motor won't rev up

[95slowhoe]

Hey guys i have a 95 Tahoe with a 5.7l and when i put it in four hi it wont rev up and barely spins the tires. And also when i put it in four low the front end wont lock in but in four hi it will. Any help would be greatly appreciated.

 

[Green monster]

Well if it's a stock Hoe I don't think it will spin tires in 4X4. With 33's on it and if it has stock gears I bet its just bogging on U, loss of torque with the taller tires.