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NP208 or 205??

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by dyeager535, Nov 8, 2001.

  1. dyeager535

    dyeager535 1 ton status Premium Member

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    Well, if I ever get a response to my inquiry about an SM465/208 combo, I may have to make that decision.

    I already have the SM465/205 combo in the truck.

    The pros of the NP205 are obvious, indestructable (in my case) and will last forever.

    Pros of the 208, IMO, are that parasitic loss should be less (better economy, maybe quieter too, but who cares), floor is already setup for it (I hate cutting holes), better low range, and is pretty strong as well. (from reviews. Although obviously not strong like the NP205, more than strong enough for my use I think)

    With a 350 being used (Somewhere on the order of a 350hp/375ftlbs motor I'm planning it to be), 95% on-road use, and with my off-road use being what I consider "light" anyways, I'm thinking perhaps the 208 wouldn't be so bad?

    If I were to get the SM465/208 combo, I would be able to re-synchro, -bearing, and -seal the 465, as well as replace the chain in the 208, before install, so not much vehicle down time.

    The one thing I *don't* like about the 208 is the (as stock) inability to just remove the rear driveshaft to move the vehicle if necessary. IMO, since a u-joint can go at ANY time, thats almost a necessity. Never really paid attention to the slip yoke eliminator set-ups, are they cheap enough that with all the rebuilding expense that I would incur at this point, that would be a viable option?

    Other problem is that the 208 could be screwed up internally as well....if it were, am I correct that the 465 with 208 has 32(?) splines and the 205 one has 10, so the 465 wouldn't be a direct interchange either?? I could do my own output shaft swap, but that would mean more work tearing both of the 465's down...

    I know its false economy in reality to say "better mileage" when all the potential savings will be thrown down the drain in the acquisition of the 208, but I figure the SM465/NP205 already have 25+ years on them, and really will need an overhaul while I own them anyway.

    Thoughts and opinions are welcome, thats why I ask.

    Dorian
    My tech/links page: <a target="_blank" href=http://www.dorianyeager.com/index2.html>www.dorianyeager.com/index2.html</a>
    Why insist on counting when the ring gear has the tooth counts stamped in?
     
  2. Hossbaby50

    Hossbaby50 3/4 ton status

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    I have a 208, and I like it. I personally though would just stick with the 205. You can't break it, and who care if it doesn't have the nice low range. Thats what the 375lb/ft is for. My 208 has 150K on it, and is still going good, but if I had to choose I'd go 205. It is one less thing you have to worry about. There is alway that little thought in the back of my mind that I might break a 208, but if I had a 205 it would be long gone. Since you have a 205 you could always get the Doubler.

    My Chevy isn't broken, its just out of gas.
     
  3. K10ANDYKHAMNIC

    K10ANDYKHAMNIC 1/2 ton status

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    i have quite a bit of experience with 208 , they are strong imo i wheel the wee out of my truck and haavent busted one , the only time ive busted em is with no skid plate to protect it otherwise they are good , i am working on a slip yoke eliminator now using a dodge 208 with a minor mod &lt;requires aluminum welding , i have 2 of them so one is going to be for sale ...i kinda miss washington ...

    WHATS WRONG WITH A 305 ?
    81 K10 GOODYEAR 35" MTRS
    TH350 NP 208
    O R D's axles
    NO BREAKAGE :)
     
  4. dyeager535

    dyeager535 1 ton status Premium Member

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    Yes, most everyones experience with the NP208, within reason (and sometimes beyond reason) seems to be pretty good. I "burned one up" in my '83, but with 130k on it, and probably no fluid changes, I don' tthink thats the transfer cases fault. I guess I don't like the idea of the case cracking if you toss the driveline either, and I don't think eliminating the slip yoke will do it. Friends sister improperly lifted her K5, and the rear u-joint let go at 60MPH. Yoke never came out, but the whipping of it cracked the case. Then again, knowing her, she probably let the engine continue to run after the u-joint broke.

    I don't think strength is an issue, longevity maybe, but it will take me many years to reach 150k on this truck...

    What about spline count? Not familiar with the input on the 208, does the tranny output shaft just slip into the t-case, or does it have a "coupler" like my 465/205 combo. How about spline count for the 208 input?

    If I don't hear back soon though from this person, it may be a moot point.

    Dorian
    My tech/links page: <a target="_blank" href=http://www.dorianyeager.com/index2.html>www.dorianyeager.com/index2.html</a>
    Why insist on counting when the ring gear has the tooth counts stamped in?
     
  5. 84_Chevy_K10

    84_Chevy_K10 Banned

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    I had a u joint let go at 70 MPH once. the slip yoke did come out. It hit the highway and broke too.

    Slip yoke 208s suck dick. Keep the 205. It won't need a rebuild.

    Tim
    '84 Chevy K10, lifted, loud, fast, and 3/4 ton axles
     
  6. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    The 465 mated to the 208 from 81 up is a 32 spline output version. I had that combo in my Jimmy when I bought it. It whined in low range...whereas the 465/205 combo I have now is dead quiet in low range. Not sure how the tranny and T-case mate up...it prolly uses a drive sleeve like the 205 does. I never separated mine.

    Rene

    <font color=green>Dyslexics of the world...UNTIE!</font color=green>
    <a target="_blank" href=http://coloradok5.com/gallery/project_T2> tRusty pics...</a>
     
  7. Hossbaby50

    Hossbaby50 3/4 ton status

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    I think all 208's whine. Mine does, and I have a 700R-4

    My Chevy isn't broken, its just out of gas.
     
  8. Blazer_Boy

    Blazer_Boy 1/2 ton status

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    I was bustin through drifts last year in low and never heard a peep. Course it had been rebuilt. Ahh, I remember that night, 11 pm and I was up to my skid plates in snow and got stuck cause I forgot to bring my shovel.

    <a target="_blank" href=http://www.geocities.com/bigkern76>http://www.geocities.com/bigkern76</a>
     
  9. DesertDueler

    DesertDueler 1/2 ton status

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    I would say go for the 208. I have put mine to trough alot as well and they hold up. Just build a good shield on them and they will last forever. The only way I would get rid of the 208 is if I got a doubler.

    86Jimmy 4"&35"MTRs,87 burb 4"&35"MT,69Firebird w/525 hp,and 70GTO live in PHX,AZ<a target="_blank" href=http://www.geocities.com/modifierperformance>My vehicles</a>
     
  10. Twiz

    Twiz 1/2 ton status

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    Why degrade the T-case?

    Sounds like alot of work to gain a minamal amount of fuel economy. -Less rotationg mass, and reduced weight would increase economy. I wouldn't think by very much though.

    I've seen one planatary gear set carrier wear out, the planatary gears are held in a stamped steel houseing and something wore-out. Sorry, it was a long time ago, and I'm not really sure of the details beyond that..The Blazer that had it, did have alot of miles on it, and was wheeld a bit too.

    If your taking a poll here, I'd stick with the 205..Just my oipnion.



    <font color=blue>Twiz</font color=blue>
     
  11. dyeager535

    dyeager535 1 ton status Premium Member

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    It wasn't all about the economy, although the Dexron ius a heck of a lot thinner than 80-90, so I'm thinking economy would actually improve quite a bit. Just a theory of mine. If and when I re-seal the 465/205, I will likely go with synthetic fluid, which should help out on the economy side, as well as just better lubrication. The price for 80-90 synthetic is apparently just a bit more than it is for synthetic motor oil, about $6-7, not on sale. Wonder if that stuff will ever go down in price!

    Anyways, I had a 208 before in my '83, and shjortly after I bought it (used of course) the planetary "melted" or so they told me when I had it rebuilt. Thats one downside of the 208, but then again, theres a difference between someone ELSE owning a vehicle, then you getting it, and something breaking, as opposed to rebuilding it yourself. I can't vouch for the history of that 208, but I could if I rebuilt it. I just don't think that with the light use I subject the t-cases to, an NP205 is necessary.

    However, all of this is now a moot point, I won't be picking up the tranny/t-case combo I was thinking I would, but I now have a new idea, which I will be posting shortly ; )

    Dorian
    My tech/links page: <a target="_blank" href=http://www.dorianyeager.com/index2.html>www.dorianyeager.com/index2.html</a>
    Why insist on counting when the ring gear has the tooth counts stamped in?
     
  12. greg83k5

    greg83k5 1/2 ton status

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    hmmmm....

    i lost the rear driveshaft one night, sucked out, and drove it 20 miles home. it got fluid all over the rear of the truck, but it still worked fine..... in retrospect, it was a bad idea, but at the time i didn't know i couldn't.....

    greg ( it's amazing sometimes what you get away with when you don't know better! )
     
  13. Chris Demartini

    Chris Demartini 1/2 ton status

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    <font color=blue>So you want to take something you have in your truck now thats bulletproof and works fine, and swap it out for something weaker that needs to be rebuilt just so you can get .0001 more miles to the gallon? Am I reading this right? Keep the 205! If it aint broke dont fix it! I had to drive another member's (Billybob) truck home with a 208 and no driveshaft and it wasnt pretty, and that was on the highway. If it was 3 miles up the mountain we would have been really screwed! If you want gas mileage get a moped! I really dont think you will see a noticable increase, at least not enough to justify all the work it would take to put it in. Arent you already getting 17 mpg or something? !
     
  14. Chris Demartini

    Chris Demartini 1/2 ton status

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    <font color=blue>So you want to take something you have in your truck now thats bulletproof and works fine, and swap it out for something weaker that needs to be rebuilt just so you can get .1 more miles to the gallon? Am I reading this right? Keep the 205! If it aint broke dont fix it! I had to drive another member's (Billybob) truck home with a 208 and no driveshaft and it wasnt pretty, and that was on the highway. If it was 3 miles up the mountain we would have been really screwed! If you want gas mileage get a moped! I really dont think you will see a noticable increase, at least not enough to justify all the work it would take to put it in. Arent you already getting 17 mpg or something?!
     
  15. four_by_ken

    four_by_ken 1/2 ton status

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    I agree with most here. Why downgrade the truck. The gas mileage differance will be so negligible you wont even be able to measure the differance.

    Ken H.

    '85 K5 in process
     
  16. 6.2Blazer

    6.2Blazer 1/2 ton status

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    While I agree with most that the gas mileage probably won't be that much of a gain, don't forget that the 208 has a pretty big advantage in low range ratio over the 205.

    I believe the 205 is something like 1.96:1, with the 208 being 2.6:1...........that's close to the same difference between 4.10 and 4.88 axle gears which would be nice if you were into trail riding.
     
  17. White Knight

    White Knight 1/2 ton status

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    I just blasted my 208 after a measly 367,000 miles, 3 engines.[​IMG]..now if they're so damned weak, how come it lasted that long?....by the way the interior parts are still functional, I just split the case after dropping about 8 feet on to the center of the truck, pushed the cross member up and cracked it.[​IMG]...IMHO the 208 is very underrated, its a great t-case!!!!!!

    White Knight
     
  18. dyeager535

    dyeager535 1 ton status Premium Member

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    bigray: You are missing my point. It wasn't all about mileage. It was about fitting in the truck as designed (floor shifter) and being able to rebuild it without taking my truck out of comission. Mileage is ALWAYS a concern when I do things on my truck, but its not like I'm going with a t-case out of some quarter sized rig like a Samurai or something just to save MPG, this is a t-case that was put up against 350's stock, and for most people is plenty strong. Again, I say most people, and to be honest, my usage is like "most people" 95% street, 5% light off road. Not enough to break one of those things. FWIW, my 208 failed on the street, but if I ran my 205 full of water or something, after 130K, I'm sure it would fail too.

    As I said, this is now a moot point, since the deal "fell through"

    Dorian
    My tech/links page: <a target="_blank" href=http://www.dorianyeager.com/index2.html>www.dorianyeager.com/index2.html</a>
    Why insist on counting when the ring gear has the tooth counts stamped in?
     

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