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"later" ('81+) 465/205 crossmembers and adapters

Discussion in 'The Garage' started by dyeager535, Sep 11, 2003.

  1. dyeager535

    dyeager535 1 ton status Premium Member

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    \"later\" (\'81+) 465/205 crossmembers and adapters

    I have the crossmember from the 1 ton 4L80E/205 that I got some parts off of. This is the crossmember with the "drop" on one side.

    From my experience there are three crossmembers (total) for the '81+ trucks...the "flat" style, for the "tall" adapters, then the "double hump" style that is for short adapters, but has "humps" on either side that apparently are for the exhaust pipe(s) to pass under, and finally the one I have, with the drop on one side, and "hump" on the other.

    With the two "humped" style crossmembers being made for short adapters, I assume those two are interchangeable. Correct?

    Lastly, anyone out there interested in giving me a "deal" on making a 465/205 adapter for the later round pattern 205? Seem to be in fairly short supply, and while I haven't checked GM yet, I imagine $200+ is going to be the price. I'm not expecting anyone to make one for less than that, as I know there will be a fair amount of time involved in a project like this, plus the specialized tools necessary.

    I keep saying someone should make these out of steel or AL, but I have little knowledge of what would need to go into the design/construction. I may be able to get my hands on a broken one, if anyone has the capability/time/interest in trying to replicate these out of better material, let me know. I have a *feeling* that this could be somewhat profitable, as these are commonly broken, and in my experience, hard to find when you need them. At least the 205 ones.
     
  2. thatK30guy

    thatK30guy 1 ton status Premium Member

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    Re: \"later\" (\'81+) 465/205 crossmembers and adapters

    [ QUOTE ]
    From my experience there are three crossmembers (total) for the '81+ trucks...the "flat" style, for the "tall" adapters, then the "double hump" style that is for short adapters, but has "humps" on either side that apparently are for the exhaust pipe(s) to pass under, and finally the one I have, with the drop on one side, and "hump" on the other.

    With the two "humped" style crossmembers being made for short adapters, I assume those two are interchangeable. Correct?

    [/ QUOTE ]

    Correct. The crossmembers go as follows:

    '81-'84, flat, tall adaptor.
    '85-'86, double hump, short adaptor.
    '87-'91, single hump on each side, short adaptor.

    The double and single hump members are easily interchangable since both utilize the short adaptors. Using a flat member can be done while using the short adaptor, but a spacer will need to be fabbed. I believe the space is around 3 to 4 inches between the bottom of the adaptor feet to the top of the rubber mount.

    There is no way to make a tall adaptor fit to the double or single hump member.

    I replied to your PM and agree with someone making adaptors from aluminum as dealer prices are high but aluminum ones can be expected to cost the same as the dealer prices. I just want the stronger aluminum pieces instead. Lightweight, too, is another plus. /forums/images/graemlins/thinking.gif
     
  3. nvrenuf

    nvrenuf NONE shall pass! Premium Member

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    Re: \"later\" (\'81+) 465/205 crossmembers and adapters

    Something else to keep in mind, I know for sure that the flat style crossmembers are different between 1/2 and 1 ton, the 1 ton crossmember is flatter than the 1/2 ton (different frame depths). I would imagine that this would hold true for the "humped" style as well.

    It will probably be Sunday before I could do it but I can verify that about the "humped" style this weekend, if needed.
     
  4. u2slow

    u2slow 1/2 ton status

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    Re: \"later\" (\'81+) 465/205 crossmembers and adapters

    [ QUOTE ]
    Something else to keep in mind, I know for sure that the flat style crossmembers are different between 1/2 and 1 ton, the 1 ton crossmember is flatter than the 1/2 ton (different frame depths). I would imagine that this would hold true for the "humped" style as well.


    [/ QUOTE ]

    This is true of the short-adapter crossmembers as well. It's because the 1-ton's frame channel is 2" taller - or rather, hangs 2" lower.
     
  5. doctor4x4

    doctor4x4 1/2 ton status

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    Re: \"later\" (\'81+) 465/205 crossmembers and adapters

    had 2 jump in on this 1
    i 2 would LOVE to have some body dup these things but
    1st there is quite a bit of work typing up the program to put something like this on the cnc machine as computers only under stand X Y Z axcess and ya have to tell it when aand were to charnge tools
    then figure a few solid block's at least 12 x12 x 4 of aircraft quality alum for pratice at about 100 each then set up and load all the tools and pray and press the green button :-) lol "wala "your first prototype is done
    any ways ya get thge idea why it is so dame expensive
    then ya gotta deal with some finicky jerk talking about design rights if ya try to sell em
    as i am sure gm hold the patent rights to each and every bolt circle pattern thats 1 of the reasons they change the styles over the years
    youd have to have somebody make ya 1 for free to protect them selves then just buy something else they are selling at a greatly inflated price
    good luck and shoot me a pm if ya find somebody and i will do some people research also ;-)
    R
     
  6. thatK30guy

    thatK30guy 1 ton status Premium Member

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    Re: \"later\" (\'81+) 465/205 crossmembers and adapters

    [ QUOTE ]
    [ QUOTE ]
    Something else to keep in mind, I know for sure that the flat style crossmembers are different between 1/2 and 1 ton, the 1 ton crossmember is flatter than the 1/2 ton (different frame depths). I would imagine that this would hold true for the "humped" style as well.


    [/ QUOTE ]

    This is true of the short-adapter crossmembers as well. It's because the 1-ton's frame channel is 2" taller - or rather, hangs 2" lower.

    [/ QUOTE ]

    While John is correct on the '84 and older 1 ton flat members being shorter than the 1/2 and 3/4 tons, the '85 to '91 crossmembers are all the same between 1/2, 3/4 and 1 ton.
    Even though the 1 ton uses a shorter crossmember, these '85 to '91 has the crossmember sitting on TOP of the lower frame rail rather than under the very bottom part of the rails like all the other non-1 tons do. /forums/images/graemlins/wink.gif
     
  7. dyeager535

    dyeager535 1 ton status Premium Member

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    Re: \"later\" (\'81+) 465/205 crossmembers and adapters

    Still haven't had a chance to check the GM price on the later adapters, but again, I don't *want* a GM piece as they are still fairly weak.

    $300 in aluminum is probably a cost I am willing to absorb. I really think that the GM piece is somewhere around that new.

    If someone wanted to make it, and felt inclined to ask for charitable donations, I don't think GM would go after them.

    Again, I understand the work that would be necessary on the side of the "developer", but if someone foots the bill for the materials, and all you have in it is time, it could work. Once you get the cutting stuff programmed in correctly, I can't imagine it would be anything more than just material to reproduce in any quantity wanted.

    According to the only place I checked with, a 12x12x10" chunk of 6061 AL is $657.00. I guess it would be less if you were going with the short adapter, but it appears, unless there is a cheaper source/alloy that will do the job, that cost of materials alone is prohibitive. Maybe if you could source it surplus or something...

    If anyone deals with this stuff on a regular basis, and has some more insight, I'd love to hear it. I think this is a great project, but only if the cost of material can be brought way down. I'm going to keep checking, but I bet someone that deals with this stuff will have a better idea who to talk to for better prices.
     
  8. doctor4x4

    doctor4x4 1/2 ton status

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    Re: \"later\" (\'81+) 465/205 crossmembers and adapters

    well C.R.S. would be the way 2 go then much much cheeper and just as stong if not stonger but it kills the tools and at 50 - 75 a bit it still would very costly mabe find somebody with a with a E.D.M I slacked on my calls for today ill try to rember 2 get on it tomorrow and monday
     

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