Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

NP208 Problem, HELP!!

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Hathaway, Mar 18, 2001.

  1. Hathaway

    Hathaway 1/2 ton status

    Joined:
    Jan 2, 2001
    Posts:
    295
    Likes Received:
    0
    Location:
    Missoula Montana
    I've got an 86 K5 with a 305 v8, TH700R4 and an NP208. When I've got the 208 in 4wd(Hi or Low doesn't matter) after a short while I lose all power going to all the wheels. It m akes kind of a grinding/whiring sound then I just stop moving. The engine doesn't die, and when I put it back in 2wd it works fine. I was told by one person that the Tcase was just flat dieing and I'd need a whole new one. If thats the case I'm screwed because I can't afford that. And another person said it might need a new chain. Can anybody give me some ideas as to what the problem is? And can this Tcase be rebuilt(would it be worth it?). Thanks for any help.
     
  2. 4GUNZ4X4Z

    4GUNZ4X4Z 1/2 ton status

    Joined:
    Aug 10, 2000
    Posts:
    3,459
    Likes Received:
    0
    Location:
    Mustang, Oklahoma
    Are you sure that it's not just slipping out of gear? I've got a 208 and it will slip out of 4lo and 4hi sometimes. It gets fustrating at times but I just throw it back into whatever gear I'm using.

    <font color=blue>Professional <font color=red>JEEP EATER</font color=red> it's a population control thing.</font color=blue>[​IMG]
     
  3. CBLAZER81

    CBLAZER81 1/2 ton status

    Joined:
    Mar 3, 2000
    Posts:
    281
    Likes Received:
    0
    Location:
    Milliken,COLORADO
    Mine's been doing that too lately.I'm blaming it on the body lift.

    Chuck
    81 Blazer
    <font color=blue>does anyone have another F#@d that I can park on?</font color=blue>[​IMG]
    <font color=red><A target="_blank" HREF=http://www.chucks81k5.coloradok5.com>http://www.chucks81k5.coloradok5.com</A></font color=red>
     
  4. ScoobyDann

    ScoobyDann 1/2 ton status

    Joined:
    Mar 9, 2001
    Posts:
    305
    Likes Received:
    0
    Location:
    El Paso, TX (Far West Texas near Las Cruses
    mine does the same thing, its bothersome but i also just throw it back in to gear, just in 4hi. 4lo is fine, i think its the chain
     
  5. bigerik

    bigerik 1/2 ton status

    Joined:
    Feb 24, 2001
    Posts:
    184
    Likes Received:
    0
    Location:
    Sonoma County, CA
    Last night, my NP208 popped out of 4Hi halfway through a mud bog race! We verified that it had 4Hi for the hours leading up to the race, but after the race--guess what? The front wheels stopped moving after the high revs and driving up a berm--that sucks! What's up with that?! My solution will be to switch in an NP205 when I have the money. The 4Hi/2Hi stations are not very positive (since the 3" body lift). When it's in 4Hi, one can easily nudge the t-case shifter into 2Hi. My dad has an NP208 w/ no body lift, and his 4Hi is sort of locked in and certainly doesn't pop out at random. Is this your same symptom? My trucks are at <A target="_blank" HREF=http://www.bigerik.coloradoK5.com>http://www.bigerik.coloradoK5.com</A>.
     
  6. jarheadk5

    jarheadk5 1/2 ton status

    Joined:
    Mar 6, 2000
    Posts:
    4,389
    Likes Received:
    0
    Location:
    PA
    I've found that I have to do a little "searching" for the 4Hi detent on my 208. If I don't "search", it'll come out of 4Hi when I accelerate, and the idiot light will go out. In the snow, my first indicator is when the truck tries to swap ends on me.[​IMG] I've got a 3" bodylift so I'm pretty sure that's what screws things up. One more reason for me to use 4Lo offroad...

    [​IMG] Semper Maintenance!
     
  7. LA Bogger

    LA Bogger 1/2 ton status

    Joined:
    May 19, 2000
    Posts:
    192
    Likes Received:
    0
    Location:
    Robins AFB, Georgia, USA
    Start looking for a NP205. Mine pop out when in 4 HI no problem so far in 4 LO..60/14 Locked 4;88 700r 208 39.5 Swampers

    Eat More Mud!!!
     
  8. Blazer_Boy

    Blazer_Boy 1/2 ton status

    Joined:
    Dec 16, 2000
    Posts:
    1,669
    Likes Received:
    0
    Location:
    Sioux City, IA, USA
    Its not the fault of the case, they don't just do this because its not the high and holy NP205 (not knocking the 205 one bit, its a great case). First off, check the linkage adjustments, seems too obvious but thats what things usually are. There are bushings on the shift fork inside the case that wear out on the NP208 frequently. With the worn bushings shifting can be difficult, it can move in and out of ranges, or do other odd things. Your library should carry the GM service manuals, these are very good books that detail repair work. You don't even have to remove the case to change the bushings. Undo the parking brake cables, rear driveshaft, skidplate, and the bolts holding the case halves. It takes a little grunting to get the halves apart but be as gentle as possible (aluminum doesn't respond well from sweet talking with a pry bar). I can't remember how to do the bushings, I've only had it apart reseal the halves. It should be fairly cheap though to do.
     
  9. pcorssmit

    pcorssmit 1/2 ton status

    Joined:
    Jan 2, 2001
    Posts:
    1,346
    Likes Received:
    0
    Location:
    Denver, CO
    Mine pops out of low constantly. Not sure about 4 hi, I can't remember the last time I used it.

    Shifter linkage is critical on the 208, if its off the range fork wears out really fast.

    Pete

    '83 K5, 350 TBI (ex 6.2), 700R4, NP208, Dana 60/14 bolt, 4.56s, Detroits, 3" lift, 15-39.5x15 TSLs
    '97 Dodge 2500 4x4 CC LB Sport, Cummins 5 spd
     
  10. HarryH3

    HarryH3 1 ton status Author

    Joined:
    May 31, 2000
    Posts:
    10,384
    Likes Received:
    2
    Location:
    Georgetown, TX
    Are you certain that the linkage is adjusted correctly since the body lift was installed? The change in distance between the body mounted shifter and the transfer case must be properly accounted for. Also make sure that the body lift isn't letting the body move forward and backward. That motion would equate to moving the shifter lever on that configuration. [​IMG]

    <font color=black>HarryH3 - '75 K5</font color=black>
    <A target="_blank" HREF=http://ThunderTruck.ColoradoK5.com>http://ThunderTruck.ColoradoK5.com</A>
     
  11. Hathaway

    Hathaway 1/2 ton status

    Joined:
    Jan 2, 2001
    Posts:
    295
    Likes Received:
    0
    Location:
    Missoula Montana
    Hunh, I posted a reply to this last night but its not showing up.... strange...

    Anyway, I don't have a body lift. I don't have a suspension lift. The blazer is bone stock, with the exception of a K&N filter (which obvioulsy won't effect a Tcase ;) ) and 31x10.5R15's up from the stock 255 or whatever they are.

    The shifter DOES NOT MOVE when it does this. I'll be driving along and it'll make like I said, a whiring sound, and all power to the front and rear is lost. I can't just slam it back in gear because the shifter is still in the exact same spot. THanks for all the input.
     
  12. Hathaway

    Hathaway 1/2 ton status

    Joined:
    Jan 2, 2001
    Posts:
    295
    Likes Received:
    0
    Location:
    Missoula Montana
    One other thing, isn't the 208 supposed to be shift on the fly? I can't shift into 4hi while the truck is moving. I've got to stop, put it in park, and shift it into 4hi. Am I mistaken that the 208 is shift on the fly or what? My girlfriend has an S15 jimmy with an NP208 in it and its shift on the fly as was a good friends s10 blazer.
     
  13. HarryH3

    HarryH3 1 ton status Author

    Joined:
    May 31, 2000
    Posts:
    10,384
    Likes Received:
    2
    Location:
    Georgetown, TX
    I'd have sworn that I read something about a body lift. [​IMG] Musta read too many posts today! There were something like 763 new for me this morning. [​IMG] The 208 is shift on the fly, sounds like something is wrong inside of yours. The shifter forks and/or bushings are what I'd check first.

    As for the chain causing the problem, I doubt it. The chain only supplies power to the front driveshaft. Power would still go to the back even with the chain broken.

    <font color=black>HarryH3 - '75 K5</font color=black>
    <A target="_blank" HREF=http://ThunderTruck.ColoradoK5.com>http://ThunderTruck.ColoradoK5.com</A>
     
  14. Hathaway

    Hathaway 1/2 ton status

    Joined:
    Jan 2, 2001
    Posts:
    295
    Likes Received:
    0
    Location:
    Missoula Montana
    Some one else in this thread mentioned that they had a body lift and it was causing theirs to jump out of gear. So no biggie :) But that wasn't my problem.

    I'm glad to hear its not the chain. I assume that would be a rather pricey fix. I'm going to call a few of the tranny shops in the area and see what they have to say, I'm getting a bit tired of crawling around in my gravel/dirt driveway fixing this thing half assed :)

    Thanks for the help

    Dan, '86 K5, 5.0L v8, NP208, TH700R4, open 10bolts front and rear, 3.43gearing, K&N filter, 31x10.50R15 Trailhandlers
     

Share This Page