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TH400 rebuild questions

Discussion in 'The Garage' started by 6.2puller, Sep 10, 2006.

  1. 6.2puller

    6.2puller 1/2 ton status

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    It appears I need a new oil pump in my TH400. Anyone have a GM part # so I can try gmpartsdirect.com ? I found a Hughes on summit for 52$ so far.
    Mine is scorred pretty evenly top to bottom on the gear and case. There are no grooves but I assume it should be smooth.

    Also I am hearing that I can increase holding strength by taking out one big steel and clutch set and putting in some smaller ones as long as the over all length is the same in the end. Would this be a good idea on a tow rig were heat is more of an issue than slippage? Wondering if the thinner steel would heat up quicker than a thicker one?

    My rebuild kit did not come with bushings so I am also looking for a GM part # for those if anyone has them. If not I found plenty of sets on the net cheap.
     
  2. 1979jimmy350

    1979jimmy350 1/2 ton status

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    the idea of a larger quanity of thinner steels and friction disks will give you more surface area which gives you more holding power which reduces slippage.
    if you are looking for bushings and hard parts look at Makco Distributing, they have good prices, i have used them a few times before. If i were you i would also look into a mild shift kit for towing, a short shift will create less heat and slippage leading to a longer tranny life

    when rebuilding a tranny being clean is very important, clean every thing till you think it is good then clean it one more time for safe measures

    good luck, hope the manual helps you
     
  3. 6.2puller

    6.2puller 1/2 ton status

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    The manual has been great so far. I have it totally disassembled now and I have cleaned the housing and started cleaning the pump when I noticed the wear on it. This tranny has been opened befor for sure. Their were moths in the pump in two places, three moths. :eek1: I think the shift kit was allready installed as their was 7 check balls in there rather than 6. I had allready ordered a B&M shift kit though and it comes in tomorrow AM.

    I realize the purpose of the extra friction and steels but I am wonderring if it makes them more susseptable to heat damage when towing?
     
  4. 1979jimmy350

    1979jimmy350 1/2 ton status

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    i would guess that a thinner steel would warp easier, but when a clutch pack is ingaged i would think the pressure would keep the heat from warping the thinner steel
     

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