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installing a torque converter into a th350

Discussion in 'The Garage' started by adamforsythe, Mar 30, 2005.

  1. adamforsythe

    adamforsythe 1/2 ton status

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    Hello,
    I am looking into installing a torque converter into my blazer. Is this hard to do?
    It is a th350 that is in my 1985 K5 blazer
     
  2. big83chevy4x4

    big83chevy4x4 3/4 ton status

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    you need to drop the tranny or pull the motor. not hard for someone whos done it a few times. i have pulling a 4wd tranny down to about 30-45 minutes.
     
  3. 74757685k5

    74757685k5 1/2 ton status

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    easy? with right tools yes.un bolt tranny and 4 bolts on tc seperate them and slide it off. yer makin a showoff truck?
     
  4. adamforsythe

    adamforsythe 1/2 ton status

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    Hello,
    I am buying a NEW...Well rebuilt 2000 miles ago Th350 and Np205. Well I got a NEW, never used b&m 2900 stall converter for $50.00 bucks off from a good friend. (Yes I know 2900 is a bit much for a k5 but hey there is only mud in maine and I am building a show truck.)
    I am doing all of the work on the truck my self (Well most of it). I have dropped trannys before but never automatics. I need to know step by step how I should do this. And yes I am going to go to napa and buy one of those how to books that cost $15.00 :mad: .

    That brings up another ????...will I have to buy new driveshafts since I am replacing my old Th350 Np208 set up?
    Thanks
    Adam

     
  5. 74757685k5

    74757685k5 1/2 ton status

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    both shafts are different
     
  6. 84gmcjimmy

    84gmcjimmy 1 ton status

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    Don't quote me, but the np205 is (i think) a different length than the 208, so you will need a new driveshaft, or get your current one lengthened.

    For dropping the th350-np208, there are 2 or so bolts holding on the dust cover, take it off. then there is 6 or so bolts on the bellhousing connected to the engine, unbolt those. unbolt the 4 bolts holding the x-case crossmember up. check to make sure nothing is in the way. take off the tranny shifter rod, and the transfer case shifter linkage. un do and watch out for or move tranny lines, and the tranny dipstick. slowly lower and remove from truck or whatever you said it was in.

    Don't follow these directions if someone else replied. I did this in december so I can't remember everything...and I had everything off the frame except the drivetrain and powertrain. and springs...etc.

    good luck
     
  7. 84gmcjimmy

    84gmcjimmy 1 ton status

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    and i forgot you have to unbolt the TC from the flywheel before you try to move the tranny. The TC just sits on the shaft of the tranny I believe.
     
  8. 74757685k5

    74757685k5 1/2 ton status

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    the 208 has a slip yoke in the t-case 205 is a fixed yoke. so at least legnthen and new end with slip yoke.front on 208 is a big ring and 205 is like whats on the axl side.so you would at least need a different cv.
     
  9. Ryan B.

    Ryan B. 3/4 ton status GMOTM Winner

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    2900 stall eh? well I have a 3,000-3,200 stall converter in my camaro, and that is not real street friendly. and i put a 1200-1400 stall converter in my k5 last time i rebuilt the tranny. just a little more stall than a stock convertor.. i was thinking the same thing, it will be good for sand and mud, and the jump outta the hole.. well i started getting into rock crawling and my tranny starts cooking with a stall converter in it.. but we know why.
    If you're gonna run a 2900-3000 stall you know this means that anything below 3000 rpms and you will be slipping and creating heat.. sometimes lots of heat. Heat is the #1 thing that will kill an auto tranny. I don't know what gear ratio or tire size you plan on, but if you're only spinning 2500 rpms on the freeway to get to the show, your tranny will be slipping the whole time because your under the 3000 rpms your stall converter needs to see.
    If you are set on going with a stall convertor, put in a manual valve body. The second time around rebuilding my th400 w/ a 3,000 stall i put in a manual valve body.. with that high of a stall and trying to cruise around with the transmission in "D" so it will shift for you, it never really knew what gear it was in, and was probably slipping the whole time... as the clutches told me. :grin:
     

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