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sm465 swap.......sux

Discussion in 'The Garage' started by clarkjw24, Jan 8, 2006.

  1. clarkjw24

    clarkjw24 1/2 ton status GMOTM Winner

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    So I pulled out my old TH350/NP205 in favor of the sm465/np205. Well first off, its very difficult to remove a tranny from a truck with 7" of lift and 42s. Anyway, I put the manual tranny in, then removed it, then put it in again, and now its got to come out once more. Seems that the release bearing is pushing through the pressure plate or something. I put the 12" hd clutch and pressure plate on it, the one with just the 3 fingers. I guess tomorrow I'll pull it again a try a stock pp and clutch disk. All I know for sure is that this sux. This is kinda a vent but would consider any advise that you may have to offer. I've put manual trannys in before but I've never had this much trouble.
     
  2. mtn. burb

    mtn. burb 1/2 ton status

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    Sorry to hear your having headaches with the swap. I'm not a gearbox tranny guy, can't really offer any help.

    You'll figure it out, and that 6.55:1 granny low will make it all worth the effort.:D
     
  3. BIG*RED

    BIG*RED 1/2 ton status

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    Well 1st off i would remove the wheels and tires and set the drums/discs on some 2x4s...it will get the tranny a lot closer to the ground..:wink1:

    Thats odd that you are having the problems, i'm running the 12 inch clutch on my sm465, and everything slid right into place and bolted right up. Is the ball socket that the clutch fork piviots on in good shape? and how is the shape of the spring/clip on the clutch fork? also did the throwout bearing come with your clutch as a "matched set" or did you get it seperatly?

    Also are you manual or hydralic linkage? could the "throw" (the distance the linkage travels) need to be adjusted?
     
  4. 78Suburban

    78Suburban 1/2 ton status

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    Hey John, sorry to hear you're having troubles. Wish I could help, but we both know I'm too much of a noob, lol. Maybe one day I'll have the courage to even attempt a swap like this. Good luck, and I know you'll figure it out.
    thanks,
    James

    PS: the motor fired right up with 40 oil psi today, you're awsome dude :bow: Thanks so much for helpin me out.
     
  5. diesel4me

    diesel4me 1 ton status Premium Member

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    4 speeds OK,but not the ultimate..

    I did exactly the same swap in a 72 K5 ago--removed the TH350/205,and bolted up the entire SM465/205 setup from the crank back from a donor K5...it was a PITA,but it went in ok and worked OK..for about a week!..

    I made the mistake of using Borg-Warner rebuilt 3 finger 12" pressure plates..the first one had one finger snap off..I was idling at a stoplight behind a nice Corvette..in "second" gear with the clutch depressed..the truck suddenly leaped forward,like I'd popped the clutch..and I bumped the "Vette" pretty good,but no damage..the huge negro driving it nearly did ME some damage though..:eek1: --guy looked like a linebacker for the NFL!!..:yikes: gulp!..

    I had to drive it for a week with the clutch "engaged" constanly..that sucked royally..had to start it up IN GEAR at traffic lights..in granny low!,and shift it like a semi without the clutch!..I had to drive it 70 miles to my parents house,and rent the U-haul tranny jack AGAIN to change it!..plus do it ALONE again..:( ..I seriously considered selling it instead..

    The second pressure plate felt funny right from the start..it chattered and shook the truck upon takeoff..a few months go by,and its free play is gone,so I readjust the linkage..soon, I cant get it into first or second gear at all,unless I crash it into reverse first,and shift lightning fast!..time for pressure plate #3!...:mad: ..I was ready to put my TH350 back in at this point--I was tiring of the heavy pedal pressure of that 12" 3 finger pressure plate too..my left leg was twice as big as the right from all the city driving!..

    I finally eneded up with a barely used like new 11" "Centerforce" clutch a friend had in his Nova that hit a telephone pole!..I wanted to go to the 12" Diaphram style pressure plate,but was out of money by this point..I never had a lick of trouble with the clutch again..and it got a good beating most of the time..but I did strip out the "coupler" between the tranny and T-case twice too..the output shaft on the tranny had severely worn splines..(older 10 spline style)..:doah: ..live and learn!..

    I loved the granny low in the SM 465,(would have loved it more if it was synchromesh like the other 3 speeds!)--but I like automatics just as much now..easier to drive,and they don't fail THAT easy..you usually get at least SOME warning before one croaks completely..I plow with all my 4x4's,and find the automatics are much easier to use,and on the drivetrain too..

    I think GM still has a bit of work to do as far as good 4x4 trannies,manual OR aoutomatics..I know the newer Alisons,"4L60" and "4l80" or whatever ,and NV5400 or whatever they call them are pretty decent..but still have issues..

    The SM465 and TH400 were the beefiest "old" trannies there were..but no overdrive,or "granny low" were drawbacks..the 700R4 is a joke in stock form,but has the right idea,with a low first gear and overdrive..the newer ones are a bitch to install in old rigs,thanks to the computer controlled shifting..they should just make a tranny like a Doug-Nash 6 speed manual that will retrofit to ALL the trucks,and make the Alison adaptable and "non-computer"as well..it would save us a lot of work!..:crazy:
     
  6. Jishory

    Jishory 1/2 ton status

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    it will all be worth it when your done man, theres nothing like that satisfaction
     
  7. RootBreaker

    RootBreaker 3/4 ton status Premium Member

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    it is worth it... funny thing is I did this kinda swap back in 1993ish.... and I had a turbo 400 with a shift kit.. will never go back to auto...

    anyway... I just did the hydro clutch swap.... and funny thing is I bought the 12" clutch and had to return it... had to go with the 11"

    what is the difference of the 12" and 11" when a smc is a smc??????
     
  8. clarkjw24

    clarkjw24 1/2 ton status GMOTM Winner

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    Glad to hear you got it done. I knew you could do it.
     
  9. clarkjw24

    clarkjw24 1/2 ton status GMOTM Winner

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    Well from the tech and advice you guys posted, I think I would have been better off going with the clutch, pp setup that was in the truck I pulled the tranny from. Sad part is it looked good and worked great (I drove the truck before parting it) so I guess I should have let well enough alone. I thought about it last night the second time I had the tranny out wondering if I should put the original stuff back on and I thought that maybe I had messed up putting the release bearing in. Now I think I'll just go buy a new stock setup with the standard fingers. I really don't want to pull this thing anymore.
     

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