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I MAY need a tranny. Replace or rebuild?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by NewK5Guy, Apr 15, 2001.

  1. NewK5Guy

    NewK5Guy 1/2 ton status

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    First of all, I have an 84 6.2 diesel 4x4. The majority of you are probably not familiar with diesels, but I'll ask here anyway since this site gets so much traffic.
    The tranny is the verable 700r4. I posted my lockup problem earlier and it does seem to be heat related. I will be adding a cooler soon. Looking for some opinions: replace or rebuild??
    The ticker on the truck reads 230+k miles. SUPPOSEDLY, the tranny has a rebuild with some 10k miles or so on it. I find that hard to believe. It was said a shift kit was added which, if it was, I believe is the cause of the problems I'm having. I can't toss in a gas tranny because the diesel 6.2 700r4 has a different bellhousing bolt pattern. Plus, there are other minor internal differences like shift points and such that make it unique to the diesel application. But, it's getting very tired and difficult to live with. Summer is coming and I personally don't think it will last. Occasionally, these VA summers can get brutal at times.
    So, should I drop it and attempt a rebuild on top of the supposed existing rebuild? I'm thinking it may need a new valve body IF a shift kit was actually put in. I don't think the shift kit was a good idea for the diesel in the first place. It may need a new valve body to boot and I don't know if I can foot that bill.
    Or, should I try to track down a new one? Jasper? Jet? To tell you the truth, I don't know if either carries the diesel version. Won't know till I ask. I'm figuring if I splurged for a new one, it would come pre-equipped with the later model updates that made the late 80's early 90's 700r4(and other incantations) a better unit.
     
  2. CaptCrunch

    CaptCrunch 1/2 ton status

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    Just my $.02 worth, but since the tranny looks kinda FUR.. then why not look for a crashed Diesel 700 combo and drop in the works. Usually you can get the 2 together for a few hundred more...maybe 500 more, depending on the age. 230k is a lot of miles, but I have seen gas TBI motor w/ this many miles on then and running fine. Diesels regularily get this kinda milage and it isn't all that uncommon to hit 300,000. Grabing a lower milage unit wouldn't be a bad idea though.

    [​IMG]
    1987 Chevy K5 Blazer- 350 TBI
     
  3. NewK5Guy

    NewK5Guy 1/2 ton status

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    Well, the motor has less than 10k miles on it. It was replaced about 3 months before I bought the truck so it will stay. It's just the tranny giving me trouble. I've thought of trying to rescue a wrecked diesel 700, but there just ain't none around here. Does anybody make a standalone controller for the 4l60e? Dreaming...
     
  4. dyeager535

    dyeager535 1 ton status Premium Member

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    I'm pretty darn sure the 6.2 uses the standard GM bolt pattern. Not sure who told you that it didn't, but I beleive that 6.2 was designed FOR GM. If it was designed for GM, I can bet you that they specified the same bolt pattern. It makes no sense to have two different ones. As far as that goes, do a search on yahoo for a 6.2/6.5 diesel powered vehicle page. i know I've seen one before, and it will tell you that.

    Shift kit should definitely not require a new valve body. Likely a new spacer plate if the old one was drilled, and the springs in the valve body were likely changed if it was decent shift kit.

    Personally I think the diesel governor shifted way too fast...the diesel is torquey, but not enough to shift at like 1800RPM WOT. The governor itself is not application specific, its the weights and springs on teh governor that are.


    Dorian
    My K5 and Chev/Olds tech/links page: <A target="_blank" HREF=http://www.dorianyeager.com/index2.html>http://www.dorianyeager.com/index2.html</A>
     
  5. Executioner

    Executioner 1/2 ton status

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    FYI, with all do respect to you, and the Tranny Industry
    I do not think you will be able to source a new tranny
    good luck
     
  6. NewK5Guy

    NewK5Guy 1/2 ton status

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    And with all do respect to you, I agree. The only reason I don't want to rebuild is because I don't know what kind of wear and tear is on the inside of a 230k mile tranny. I don't know what point in mileage you have to reach before a tranny is not rebuildable.
     
  7. dyeager535

    dyeager535 1 ton status Premium Member

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    I wouldn't be so much concerned with having used parts. Using old parts (they are called "hard parts" for a reason, they don't wear out unless something major goes wrong) has been standard in the rebuilding industry for probably as long as there have been transmissions.

    Theres just no way that you could put a tranny together from new parts and be under $1000. I believe at one time I heard the most expensive component of an automobile IS the transmission. Check on prices of "new" hard parts, like a planetary assembly alone for a 700.

    If you plan on rebuilding it yourself, then you may have problems discerning what is proper wear, and what is indicating a potential failure. If a shop is going to do it, and I must stress REPUTABLE shop, especially with a 700, I wouldn't worry about it. Let them do that.

    Think about wear this way...an automatic transmission, and basically every component in it, is completely lubricated most of its entire life...you aren't concerned about your 230k ring and pinion/bearings are you?

    I'm not insulting you, just trying to put it in perspective...

    Dorian
    My K5 and Chev/Olds tech/links page: <A target="_blank" HREF=http://www.dorianyeager.com/index2.html>http://www.dorianyeager.com/index2.html</A>
     
  8. NewK5Guy

    NewK5Guy 1/2 ton status

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    None taken. I understand what you're saying. I had a reputable shop do my AOD with fantastic results(not to mention a fantastic 12 month warrenty). As far as the wear, I understand that, too. It's just that a tranny is abused more than a set of gears.
    I'll have it diagnosed soon and get an idea of where to start.
    Damn. Seems can't get one fixed in time for the other to break down. I ain't never gonna get outta this (&@#$( apartment.
     
  9. Tybee

    Tybee 1/2 ton status

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  10. Tybee

    Tybee 1/2 ton status

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    Never mind saw your post there.

    1984 GMC Jimmy 379 diesel, 700R4, 3.73s, 31 x10.50 x 15
     

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