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Transmission problem

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by sting, Aug 16, 2000.

  1. sting

    sting Registered Member

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    I have a 84..350 vortec new ..around 340hp..3;08's...The 700r tranny is stock...shifts terrible at low speeds
    Jet transmissionssay they can correct my problems with new one with all mods and new torque conv.
    for about 2000$...Can a local transmission shop do the same mods..? is there a special torque converter
    that i can match up with 340HP and 3.08 rearend???? will a transmission cooler help..its hot in Texas..
    are the corvette mods helpful??? Thanks John
     
  2. Blue85

    Blue85 Troll Premium Member

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    I just did a 700r rebuild myself. I used a B&M super transkit and now the shifts are awesome. I also used a Corvette torque converter because it has a stall speed of 1996 and can still be had at the price of a stock replacement reman. converter (I paid $115). With your high gears in the axles and high horse motor, I would recommend a stall speed higher than stock, but not too high, since it is a 4x4 and probably doesn't run a huge cam, right? I don't know what all Jet does to their trannies besides paint them black, but I do know that all of the stuff that B&M does to thiers is in the box: new friction materials, upgraded valves for the 1-2 shift, a high flow upgrade for the oil pump and lots of little mods to make the shifts firmer. The 3-4 clutch is also highly modified to help compensate for the "clueless" nature of the chevy overdrive ("I want 4th, no, 3rd, no 4th...). While I had mine apart, I also upgraded the forward sprag clutch and the oil pump to '87 or '88 units, to overcome some of the inherent weaknesses of earlier 700R-4s. 82's sucked and 87's were pretty decent. The changes were gradual over the years, so everything in the middle has reliability somewhere in the middle. I didn't do the Corvette servo because my servo was in good shape and that is something that is easy to change later with the tranny in the vehicle if necessary. BTW, there is only one servo because a thm700 only has one band. It is for 2nd and 4th gears. All other gear changes are accomodated by the 5 clutch packs. Let me know if you have any questions.

    BTW, what do you mean by "shifts terrible at low speeds"?

    '85 JIMMY
    '90 paint/grill/trim 5"susp 33/12.5/16.5
    Fresh 350 B&M '87 TH700
     
  3. talldogg

    talldogg 1/2 ton status

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    Blue,
    Just wondering where you scored the converter so cheap?
     
  4. LittlePig

    LittlePig 1/2 ton status

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    Yes, a local tranny shop should be able to strengthen you r 700 for a lot less. Essentially, you should have the pump upgraded, and more clutchpacks, the usual stuff for any trans. The thing that always kills the 700 is heat, so definitely get the biggest cooler you can, and if possible, have it plumbed so hot fluid goes through it, then through the stock cooler in the radiator, then back to the trans. You might even consider an extra fan just for the cooler. Also, if you can get a torque converter with a lower stall speed, this will help, since the slippage in the converter adds a lot of heat to the system.

    Email: xiaozhu@my-deja.com
    ICQ: 84108805
     
  5. sting

    sting Registered Member

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    Just want to thank everyone for the advice,great web site...! thanks John
     

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