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.

Difference Between NP205 & 208

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by SAVAGE1, Feb 16, 2001.

  1. SAVAGE1

    SAVAGE1 1/2 ton status

    Joined:
    May 22, 2000
    Posts:
    1,104
    Likes Received:
    0
    Location:
    BAY AREA, CA
    I was just wondering if one is stronger or better than the other. My 85 has a 700r4/208 combo and it feels like it's gonna crap out on me soon. I have found a couple guys selling 208's and 205's. I need some advice on which one to go with. Does this sound like a good deal:

    <font color=blue>Turbo 350 trans w/torque converter & NP205 T-case. Shifter, coupler, & adapter for T-case included. Pulled out of a 3/4 ton Chevy Suburban. $400 OBO for all.</font color=blue>

    Would this stuff work in my rig?

    Rod



    BLAZER FOOD!!
    [​IMG]
     
  2. talldogg

    talldogg 1/2 ton status

    Joined:
    Jul 26, 2000
    Posts:
    754
    Likes Received:
    0
    Location:
    San Diego, CA
    Savage,
    First of all why do you say that your t-case is gonna crap out on you? You might want to look into that before you fork out "Blazer food" on a new set-up.
    There's major diferences between the 205 and 208. The 205 is a steel case that is gear driven, this thing is bulletproof. The 208 is a chain driven aluminium case. Not as strong nor durable. An important consideration concerning t-cases is that they're not exactly what you'd call interchangeable. Each t-case is built for a particular application. The spline on a 205 might be 32 tooth or 27 tooth. If it's 32, then it only mates to a TH400. The 27 tooth will mate to a TH350 and 700r4, so you could just swap the 208 for the 205, but you'll have to replace the driveshafts too. The deal sounds pretty good, it'd be better if you pick up the front driveshaft too, the rear you'd have to get somewhere else. Just so you know, by swapping in the TH350, your first gear won't be as low and you'll loose the 30% overdrive.

    It's not what you buy, it's what you build!
     
  3. SAVAGE1

    SAVAGE1 1/2 ton status

    Joined:
    May 22, 2000
    Posts:
    1,104
    Likes Received:
    0
    Location:
    BAY AREA, CA
    My 700r4 doesn't even shift into OD. From what I understand the 350 is a stronger tranny. If I go with the 350/205 combo will the driveshaft lengths change any?

    BLAZER FOOD!!
    [​IMG]
     
  4. HarryH3

    HarryH3 1 ton status Author

    Joined:
    May 31, 2000
    Posts:
    10,384
    Likes Received:
    2
    Location:
    Georgetown, TX
    NP205 Case: Cast Iron. Big, beefy, strong.
    NP208 Case: Aluminum. Use a good skid plate!

    NP205 Gears: Heavy steel gears. Like you'd find in a manual tranny.
    NP208 Gears: Planetary gears. Like you'd find in an auto tranny.

    NP205 Front Drive: Driven via those heavy steel gears.
    NP208 Front Drive: Driven via a chain.

    NP205 Low Range: 1.96:1
    NP208 Low Range: Somewhere around 2.6:1

    The 205 is a stronger transfer case. But the 208 is pretty strong plus is has a much better low range for slower crawl speeds.

    When you say "It feels like it's gonna crap out on me soon", are you talking about your tranny or t-case?

    Your crawl ratio in low range is going to change quite a bit by losing both the better low range of your current t-case plus the lower 1st gear of your 700r4.

    Let's assume a 4.10 ratio and look at the numbers in low range:

    (1st gear ratio) * (low range ratio) * (axle ratio) = (overall crawl ratio)

    700R4/208 Combo:

    3.06x2.6x4.10=32.6196

    350/205 Combo:

    2.48x1.96x4.10=19.92928

    (I'm not sure the 1st gear ratio for the 350 is exact, but it's close enough to show the point). [​IMG] There's a pretty big difference.


    <font color=black>HarryH3 - '75 K5</font color=black>
    <A target="_blank" HREF=http://ThunderTruck.ColoradoK5.com>http://ThunderTruck.ColoradoK5.com</A>
     
  5. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

    Joined:
    Jul 23, 2000
    Posts:
    36,169
    Likes Received:
    1,366
    Location:
    E-town baby!
    The 208 is not a bad case. If you like aluminum housings, slip yokes and chain drives. Better crawl than a 205, but how good does something crawl when its broke?[​IMG]
    How about if you grenade the rear driveshaft on the trail? The 208 has a slip yoke so you 'll lose all the t-case fluid plus won't be able to drive out under your own power. Most 205's are fixed yoke T-case's, so if you destroy your rear driveshaft, you can unbolt whats left and drive out with Front Wheel Drive[​IMG]
    If you want crawl ratio, go with the SM 465/NP205, with 4.10's it'd have a 52.6 to 1 crawl.[​IMG]
    You can also twin stick a 205, similar to the Atlas II.

    Rene (Biased opinions given free[​IMG])

    [​IMG]
     
  6. DieselDan

    DieselDan 1/2 ton status

    Joined:
    Jan 27, 2001
    Posts:
    1,056
    Likes Received:
    0
    Location:
    Vermont
    Yes, a 205 is stronger than a 208. But how strong do you need it? I've run a 208 behind my 700R/6.2 (diesel torque!) rolling on 35" tires. Never had a problem with the transfer, now the trans.....that croaked! I rebuilt mine, with help, and utilized all the latest HD tricks. The 700R (stock) will give up long before the 208 does. IF your transfer (chain stretched?) is bad just swap in another 208 and get a modified (like JET Company) transmission.
     
  7. elkboy

    elkboy 1/2 ton status

    Joined:
    Aug 18, 2000
    Posts:
    293
    Likes Received:
    0
    Location:
    Hillsboro Oregon
    If your a cheap S.O.B. like me, go for the 205. I'm building a trail rig and just swapped out my 700R4/208 for a TH350/205 while it was still working. A fresh TH350 with B&M shift kit, low RPM stall converter cost me $450.00 plus $275 for a used 205 ( Its a slip yoke, but you can't win em all). All together much cheaper than rebuilding a 700R4 or the t-case, plus selling my still working 700R4/208 trans and t-case will pay for half the new stuff. I torched a 208 in an 85 I had because one of the fine auto hubs engaged on the highway. That was $1k bill to replace half the case that shattered all over the highway. I had a 205 case in a 78 that I abused for years and never had a problem. I'm sure I'll miss the low first gear in the 700R4, but not the repair bill. You will need new drive lines, you will have to move your cross member forward a couple of inches, and you will need a new kickdown cable. Other than that the swap is not to bad. $400.00 sounds like pretty good deal if they work. That will save some of that $blazer_food for somthing cool.

    [​IMG]<font color=red> Elkboy</font color=red> [​IMG]
     
  8. FWP

    FWP CRS

    Joined:
    Oct 11, 2000
    Posts:
    3,845
    Likes Received:
    3
    Location:
    Prescott Valley, AZ
    "If you like aluminum housings, slip yokes and chain drives. "- <font color=blue>and less weight</font color=blue>[​IMG]
    "How about if you grenade the rear driveshaft on the trail? The 208 has a slip yoke so you 'll lose all the t-case fluid plus won't be able to drive out under your own power."-<font color=blue> Have the rear output seal prepared with a cap on it for just that circumstance</font color=blue>[​IMG]

    Sorry man, had to dog ya[​IMG], as I haven't found the 465/205 combo available together for a decent price[​IMG]

    [​IMG]
     
  9. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

    Joined:
    Jul 23, 2000
    Posts:
    36,169
    Likes Received:
    1,366
    Location:
    E-town baby!
    Its all good, I was expecting Harry to do it though![​IMG]
    You're right there is a downside to everything and a solution for most things. I used to have a SM 465 and a 208, but I found a 14 bolt, Dana 44 8 lug and a SM465/NP 205 package deal and couldn't pass it up. $550 for all. I like overkill, I'm still looking for that elusive Dana 60 for under $400 [​IMG]

    Rene

    [​IMG]
     
  10. walt88

    walt88 1/2 ton status

    Joined:
    May 24, 2000
    Posts:
    430
    Likes Received:
    0
    Location:
    Monmouth County, NJ
    I have a 208 in mine, and i was wondering how do you know if the chain is "stretched"?

    <font color=red>1988 Chevrolet K5 Blazer, Middletown, NJ (07737).</font color=red> wkeil@home.com
     
  11. elkboy

    elkboy 1/2 ton status

    Joined:
    Aug 18, 2000
    Posts:
    293
    Likes Received:
    0
    Location:
    Hillsboro Oregon
    Rene, if you find two of those Dana 60 for $400.00, let me know [​IMG] . I missed a 79 K30 single rear wheels, 6 cyl for $800.00 last month. I was going to buy the whole thing for the front axle. One of these days I'll find one for under a grand.

    [​IMG]<font color=red> Elkboy</font color=red> [​IMG]
     
  12. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

    Joined:
    Jul 23, 2000
    Posts:
    36,169
    Likes Received:
    1,366
    Location:
    E-town baby!
    If I ever find a Dana 60 for $400 or under I'll be jumping on that like a fat kid on a smartie! [​IMG] If I find two I'll know I've died and there is a heaven.
    On a similar note, I know a guy here that found an NV4500 for $150....Canadian. Thats about $100 US. Unfortunately it ended up in his YJ[​IMG] Why can't I have luck like that?

    Rene


    [​IMG]
     
  13. DieselDan

    DieselDan 1/2 ton status

    Joined:
    Jan 27, 2001
    Posts:
    1,056
    Likes Received:
    0
    Location:
    Vermont
    A stretched chain will slap inside the case and in some instances jump sprockets when in 4wd (you can hear it). The get stretched usually from abuse (alot of forward to reverse, and back action, to get unstuck). I've only seen one 208 suffer a bad chain, but two or three 242 (in HMMWVs, don't ask).
     

Share This Page