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Gen2 Dblr

Discussion in 'OffRoad Design' started by K5 NUTT, Feb 6, 2001.

  1. K5 NUTT

    K5 NUTT 1/2 ton status

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    Steve...saw an add of yours about the Gen2 dblr in one of the off road rags....was wonderin what the Gen 2 was all about....basically you lose 3 inches from the previous design which gives us k5's more rear driveshaft...correct? But...on your site i see no th350 models...as the th400 NP205's are harder to come by...why did you go that route first as apposed to the th350? Just curios.

    Azblazer

    1979 K5
    1976 K5 Chalet
    1972 K10 Suburban
     
  2. Stephen

    Stephen 1/2 ton status Moderator Vendor

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    The 400 version is the first, a 350 version is to follow, don't ask when, I don't know yet. Then we may do a 465 version also, but we're a little leery of that since they tend to wear a good bit and we don't want our parts to wear out.
    Most guys convert 205's instead of finding the 400 version. We've got the parts to convert them and it's relatively economical.
    We don't feel too bad about only having the 400 version ready now since it is the best setup available. It's the strongest most durable shaft we could come up with.
    thanks

    Making the world better, one truck at a time.
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  3. TX Mudder

    TX Mudder 1/2 ton status

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    Could you elaborate a little on 465 'wearing out' comment?
    I know the output shaft is 10-spline (bad) so is this where the problem is? What exactly is happening?
    If someone (say, me) has a 205/465 and wants a doubler without having a significant weak point, what would he do?
    TIA,
    -- Mike
     
  4. Boss

    Boss 1/2 ton status Author

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    Quote:

    "Most guys convert 205's instead of finding the 400 version. We've got the parts to convert them and it's relatively economical"

    Steve, You say you carry the parts to convert my Np205 (mated to Th350) 27spline shaft to convert to a Th400 32 shaft?? If so, how much do you sell them for??? You say its economical, that would be a great.
    Boss

    <A target="_blank" HREF=http://www.boss.coloradok5.com>http://www.boss.coloradok5.com</A>
     
  5. Stephen

    Stephen 1/2 ton status Moderator Vendor

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    Ok, I'll go into a couple of these questions at once.
    The problem with the 465 version 205 is the 10 spline shaft. The 10 spline connection wears more than we like to see. It's pretty strong, but durability is not so great. You guys with the 465-205 will probably notice that the drive sleeves tend to wear and get loose in 50K or so miles, then can get worse and fail pretty quick after that. This depends on usage of course. The TH350 27 spline wears better and the 32 spline doesn't ever wear.
    We don't want to build an expensive shaft for our Doubler kit that will wear and get sloppy in a couple of years. I know other shops don't have any problems doing this, but we're looking into a little deeper to make sure it's something we want to do.
    As for the conversion parts, I'll try to find a back post on this and copy it in.

    Making the world better, one truck at a time.
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  6. Stephen

    Stephen 1/2 ton status Moderator Vendor

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    Ok, you wanted info, here it is:!!! This is right from a previous Doubler post, so it goes over some stuff that's redundant, but cut and paste is easy!
    Ok, the GEN2 requires a 32 spline female input gear. You have to use the "short" version input gear. We've found 2 32 spline female input gears, one sticks out of the case about 1 1/4", the other sticks out of the case about 3 1/2". For the GEN2 you have to have the short stickout. Luckily, the short gear is the most common, the long one appeared mostly in later 205's (86ish and up) with the round bolt pattern.
    As for the case pattern, we can do either the round pattern, or the Fig 8 pattern, no problems either way. Or you can put a Ford 205 on it, or even an Atlas.
    Now, if you don't have a 32 spline input gear.....2 options, one is to modify your case to the 32 spl., the other is to wait. More on waiting later. (get it, wait on waiting...ok, back to work) There are 2 basic cases available in the NP205, (we're not going to talk about the round pattern here since they were all "big input") One has the "small input" the other is the "big input". This refers to the size of the input gear bearing itself. The 27 and 10 spline (TH350 and SM465 versions) use the "small input", the TH400 uses the "big input". The difference in the hole in the case is over .300". To modify a case with the "small input" you just cut (mill usually) the hole to the bigger size. Then you can install the 32 spline input gear and you're ready to go for the GEN2 Doubler. We also have a 205 case exchange going on here where we send you an empty 205 case with the input hole already bored out, and you send us your empty 205 case back as a core. The cost for the service is $100, and the core charge is $200.

    Now, on the 10 spline, in factory applications, the 10 spline connection tends to wear out somewhere around 80-100K miles, depending on usage. The drivesleeve (female splined coupler) is soft enough that it wears out and creates a good deal of backlash in the system. If it wears enough to strip out, you stand a chance of ruining one or both of the shafts. We're researching what it would take to build a system that won't wear out. A big factor we're keeping in mind is that most of the trucks with Doublers in them are or become vehicles that don't see many miles. The miles they do get are pretty rough, but overall, the numbers aren't really high. So, some wear may be acceptable.
    For max durability, the 32 spline is the way to go. It's fine enough that wear isn't an issue and strong enough that you'll rip outputs out of the 205 before you break an input. In the real world, you'll either spin the tires, or break a ujoint, axleshaft, or other driveline part.
    I think this answers the questions, whew!

    Ok, price for the case exchange is up in the text, cost for the new input gear ($140) and bearing ($30) is $170, and if you want, we have rebuild kits for the 205 that are about $190, and include all the overhaul parts, including the big bearing for the TH400 gear. So buying the rebuild kit saves you buying the bearing for the gear.
    Hope this helps get it all straight.



    Making the world better, one truck at a time.
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  7. rich

    rich 1/2 ton status

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    What about a 1980-newer SM465 with the 32-spline long output shaft? Is this more durable than the older 10-spline SM465's?

    Would a 32-spline SM465 use the same female 32-spline T-case input gear as the TH400?

    What about the T-case adapter (like for an NP203 or NP205) - is it the same as for the older 10-spline SM465's, or would I need a different adapter because of the different shaft?

    I have a 32-spline SM465 in an '84 Jimmy mated to an NP208. I'm just trying to figure out how to mate an NP203 (for doubler) or older NP205 (no doubler) to it. Would I have to change the output shaft of the trans to 10-spline?

    Thanks!

    Richard
    Raleigh, NC
    '90 K-5 Blazer - stock, daily driver
    '76 K-5 Blazer - 14-bolt FF, 4.10's, locked front and rear, 36's, SM465/NP205
     
  8. Stephen

    Stephen 1/2 ton status Moderator Vendor

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    There are newer versions of the 205 that will directly interchange with your 208, but they're pretty rare, so you'll probably have to find an older 205 and swap the output shaft. The older versions require the 10 spline output. There's not much room for variation here. It might be wise to measure a factory adapter and your ouptut shaft and see if you could modify a factory old style housing to retain the 32 spline output. There's a chance that will work.

    With the 203, the factory way is with the 10 spline shaft. We're looking into building our own adapters and trying to use a fine spline input for the 203, but it won't be your shaft since the setup would be so long. We may be able to remachine a 203 face to bolt up directly in place of your 208, but again it's going to end up pretty long for a k5.

    Give us another couple of months and we may be able set up a fine spline short adapter. If we keep working on it we'll be able to make it to where you'll have front driveshaft problems again!
    Thanks
    SW

    Making the world better, one truck at a time.
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    SW-ORD
     

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