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.

how strong is my 70 dana 20 transfer?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by ryanNC, Dec 7, 2000.

  1. ryanNC

    ryanNC 1/2 ton status

    Joined:
    Dec 7, 2000
    Posts:
    182
    Likes Received:
    0
    Location:
    North Carolina, Valdese
    I just finished my 475 hp 406 sm. and already spit the spider gears through my inspection cover on my 12 bolt. I fixed that with a Lock-Right. I now my SM465 will hold up.
    I'm just wondering if I need to np205 swap now?
     
  2. fr8train

    fr8train 1/2 ton status

    Joined:
    Aug 2, 2000
    Posts:
    1,712
    Likes Received:
    0
    Location:
    Maryland
    I would in err. in favor of hind sight and go with the NP 205 setup. I wouldnt put it past a built mill to chew up anything. Its just the duration of replacing stuff can get real old real quick , not to mention expensive.

    "Lord have mercy on my next thirty years"
     
  3. SilverJim

    SilverJim 1/2 ton status

    Joined:
    Sep 23, 2000
    Posts:
    105
    Likes Received:
    0
    Location:
    Evergreen
    I just finished putting an NP205 behind my SM465, but the weird thing was that when I went to put the body back on , the transfer case was too high...the body rested on the t-case! So I got a 3" body lift and all was well. This problem could have been solved by lowering the t-case i suppose, but my oil pan on my big block is already too close to the front x-member for comfort. Just thought I would throw in my limited experience with that...curious though...does anyone know if the x-members for trucks with an NP205 are different than the ones with Dana 20s?

    1970 GMC Jimmy 502HO/SM465/NP205 doesn't run just yet!
     
  4. HarryH3

    HarryH3 1 ton status Author

    Joined:
    May 31, 2000
    Posts:
    10,384
    Likes Received:
    2
    Location:
    Georgetown, TX
    I'm not sure what kind of abuse a Dana 20 can take, but installing the Lock-Right in the 12-bolt only fixed the current problem. [​IMG] I hate to rain on your parade, but if you pound the truck with that engine and a manual tranny, next thing to happen will be bits of ring gear popping out through the inspection cover. [​IMG]

    After blasting through 3 12-bolts in 3 years in a previous K5, I decided to figure out how to install a 14-bolt FF under my current one! I haven't managed to bust teeth off of that 10.5 inch ring gear yet. [​IMG]

    <font color=black>HarryH3 - '75 K5</font color=black>
    http://ThunderTruck.ColoradoK5.com
     
  5. Blazer1970

    Blazer1970 1/2 ton status

    Joined:
    Feb 17, 2000
    Posts:
    1,600
    Likes Received:
    0
    Location:
    Old Mission, MI
    SilverJim, having swapped from a 3 speed Saginaw/Dana 20 in my '70 Blazer to an SM465/NP205, I can tell you that the cross member for the NP205 has about an inch more drop in it to clear the 205. I started putting mine back together with the old cross member, and had the same problem you did. Fortunately I had a complete parts truck with the correct cross member. To the original question, I think the Dana 20 is pretty stout, as someone else said, the 12 bolt is probably still the weak point.

    Tim

    70 Blazer CST 4X4 350 SM465 NP205
    87 Burb 4X4 350
    01 GMC 2500HD 4X4 Duramax/Allison
     

Share This Page