4x4 grinding noise
 

on my 89 s10 blazer 4.3L v6 i get a terrible grinding noise when i engage and disengage 4hi or 4low. once engaged they work and sound fine but getting to and from sounds horrible. i think the Tcase needs to be replaced. any ideas would be greatly appreciated.

Is the sound coming from under you or from in front of you?

If it is from in front of you, it likely is a problem with the front axle engagement. Either the vacuum actuator is not properly pulling on the cable (bad actuator, bad vacuum line or poor vacuum source), the cable could be froze up somewhat - just needing some WD40 or other suitable lubricant to free it up, or the shift fork and/or collar inside the front axle is somehow messed up.

it sounds like it is coming from directly below me. i can feel the grinding in the 4x4 stick on the floor as i engage or disengage 4x4

Are all ur tires the same size?

yeah all the tires are the same