Hi everyone. i have a 84 k5 blazer with a np208 transfer case. I believe the chain has some slack, because this terrible grinding sound was coming from the case. So when i put it into 4wd, it went away because of what i was told was a load was being put on the chain. Well i was driving it untill i can afford to fix it, but today, i lost all power. the motor was revving but the truck was going no where... my friend looked underneath and he thought the drive lines werent spinning.

Im on a budget here, and am wondering the best way to tackle this problem. do you have any ideas of what might be wrong. the fluid was a little low but not much. I have two np208 transfer cases in my garage. one in the truck (broken) and another that i took out, the other was was making a clunk sound when i put it in gear. How hard is it to rebuild? or should i just take a chance on another used one? whats the best thing to do?

 

Sounds to me like you may have toasted the tranny. Check and make sure the shifter and linkage on the t-case are operating correctly. Put the tranny in nuetral and the t-case in low range, then put the tranny into drive... anything? Try all forward gears and reverse. To check and see if the t-case has "lost connection" with the tranny, put the tranny into park and make sure the t-case is in 4hi or 4lo. Try to push the truck, you should not be able to move it. Like I said... sounds more like the tranny.

 

my question is, why would it be the tranny? the transfer case was what was grinding, and the grinding when away when i put it in 4wd. if it were the tcase to go out, wouldnt it show the same symptoms? ie not engaging?

you were right, i can move the car in park etc. i shifted the car to drive in 2wd, 4 hi, etc, and i get nothing to engage. but when shifted from neutral to drive, i can still hear something working, just not engaging. the tranny was rebuilt and has less than 4000 miles on it.

now when i shift to park, it (sounds like the same sound that was coming from the tcase) makes a grinding sound...

 

Yea, you got something broken inside the t-case. The tranny made that noise because the shaft was spinning when you shifted it back to park. Time to look for a new t-case or rebuild it.

 

Definitely sounds like something is not working correctly inside the transfer case. There are quite a few resources online for rebuilding the NP208. It was a popular transfer case.