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do all 700r4 use a computer

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by HispanicPanic, Apr 6, 2001.

  1. HispanicPanic

    HispanicPanic 1/2 ton status

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    reason i ask is to see if a get one for my 75 and well we all know the closest i got to a computer is my CD player and can i keep my 203

    <P ID="edit"><FONT SIZE=-1>Edited by HispanicPanic on 04/06/01 09:42 AM (server time).</FONT></P>
     
  2. Sammy

    Sammy 1/2 ton status

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    As far as I know, my 700r4 in my 88 does not use one.


    "K5 Grand GT Blazer Silverado in the Netherlands."
     
  3. CaptCrunch

    CaptCrunch 1/2 ton status

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    I believe the '82-84's didn't run off the ECM, but they do have a little separate box that they use that is separate from an engine computer. Also painless wiring as well as others make a kit for swapping in the 700 to non-computerized applications. It is under $50... also most tranny shops can wire it for about $50 or $100.

    [​IMG]
    1987 Chevy K5 Blazer- 350 TBI
     
  4. Wheels

    Wheels 1/2 ton status

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    The only part of the 700r4 that is "computer controlled" (AKA - ECM) is the torque convertor clutch (TCC) lock up on the 87 to 93 models (which has an aux valve body to soften the TCC and 3 - 4 up shift). The wiring on these models can be modified with either a Painless wiring kit ($150) or Fitzall also makes a kit for these. Earlier models (82 - 86) had a wire going to it for the TCC but it ran of the 3-4 pulse switch. 82 to 85 valve bodies can be modified to make the TCC a hydraulic lock up. The Painless kit is a real no-brainer to install, however, I would add a temperature switch in the water goose neck to switch the vacuum line on after operating temperature is reached. Mine would kick in and out of lockup until everything warmed up properly. Also, correct me if I'm wrong, and I have been wrong in the past, but I believe that the park/neutral safety switch is actually located on the steering column along with the reverse light switch and not in the tranny.
     
  5. pcorssmit

    pcorssmit 1/2 ton status

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    Correct, the reverse light switch and nuetral safety switch are both housed in the same switch located toward the bottom of the steering column.

    On my '83, the only wire going into the trans is for the TCC. It is hot whenever the key is on, and the brake pedal is NOT depressed. The trans shifts fine without the wire hooked up, but the TCC doesn't lock up. This is not adviasable as the trans temps run much hotter.

    Pete

    '83 K5, 350 TBI (ex 6.2), 700R4, NP208, Dana 60/14 bolt, 4.56s, Detroits, 3" lift, 15-39.5x15 TSLs
    '97 Dodge 2500 4x4 CC LB Sport, Cummins 5 spd
     
  6. CaptCrunch

    CaptCrunch 1/2 ton status

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    yeah... running w/ no TCC will fry it in no time flat.... had one come in the shop last year... poor kid just wanted to upgrade his 82 Camaro... he was pretty cool and I actually ended up doing it off the clock for 100 bucks (It's gravey job) which I rarely do... but since he has all his buds bring his cars to the shop and ask for me... +good money/ -they are all roaches.... win some... lose some.

    [​IMG]
    1987 Chevy K5 Blazer- 350 TBI
     
  7. HispanicPanic

    HispanicPanic 1/2 ton status

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    so i guess it doesnt matter what year i get as long as get the painless wiring kit for it right?

    <A target="_blank" HREF=http://jimjim.coloradok5.com>http://jimjim.coloradok5.com</A> [​IMG]
     
  8. pcorssmit

    pcorssmit 1/2 ton status

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    From what I understand, the '87+ units are better, and avoid the ones built before Oct. '84 like the plauge.

    OK, time for a question of my own.

    I had mine ('83) rebuilt about 5 years ago. I've been limping it along for a couple years now. While I don't expect it to last more than another year or so, I would like to figure something out. I won't say that it works great, but everything is more or less at the bottom end of acceptable except the 3-2 shift. Whenever the trans tries to go from 3-2, whether forced or automatic, it slips really bad and you have to play with the throttle to get it to grab. I don't drive the truck much, and am hoping to get another year out of the trans, but would really like to at least band aid fix this problem.

    The trans was rebuilt for the diesel that used to be in the truck. Its still has a diesel converter (replaced when the trans was rebuilt), it has a (crappy) B&M shift kit, and a govenor for a police spec Caprice. First gear holds fine, as well as third and fourth. I can also run WOT in 4th, not sure if thats a diesel thing or what, but it works. No problem hitting 5000 rpm in 4th in low range.

    The current motor is a 350 TBI that is internally stock, the only power add ons are exhaust and an MSD 6AL.

    Thanks,

    Pete

    '83 K5, 350 TBI (ex 6.2), 700R4, NP208, Dana 60/14 bolt, 4.56s, Detroits, 3" lift, 15-39.5x15 TSLs
    '97 Dodge 2500 4x4 CC LB Sport, Cummins 5 spd
     
  9. dyeager535

    dyeager535 1 ton status Premium Member

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    I would be suspecting that its the 2nd gear band/drum that have warped or worn. 2nd gear clamps around the drum, stopping its rotation if I understand second gear correctly. The problem I believe was in GM's desire to make the tranny shift "soft" and it just doesn't clamp the band on tight enough, fast enough, so it heats up the drum, warping it, and burning the band up. By revving the motor up, you are increasing the fluid pressure, and it's clamping harder.

    Also as far as I understand, thats what the Corvette servo is supposed to fix..much more apply pressure to the band, and likely faster apply, when the tranny needs to hit 2nd.


    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>
     
  10. pcorssmit

    pcorssmit 1/2 ton status

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    I thought about that, but when I fried the 2-4 band a few years ago, I had no 2nd or 4th at all. The way it is now, 2nd is ok once it finaly grabs going from 3-2, and it shifts (more or less) ok from 1-2. 4th seems fine.

    Pete

    '83 K5, 350 TBI (ex 6.2), 700R4, NP208, Dana 60/14 bolt, 4.56s, Detroits, 3" lift, 15-39.5x15 TSLs
    '97 Dodge 2500 4x4 CC LB Sport, Cummins 5 spd
     
  11. dyeager535

    dyeager535 1 ton status Premium Member

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    No computer=fried 700 appears to be partially a myth. If you install a large tranny cooler you should not have any problems. Obviously the 700 is borderline from the factory in the way of cooling, or 3-500 RPM of slippage (at most) wouldn't fry the thing.

    To me TCC is most definitely worth the benefits, so I wouldn't consider running without it. However, you shouldn't have any problems doing so.

    Buying a used 700, then running it, and having it fail, without the TCC connected, does not prove that they will fail when the TCC is disconnected.

    FWIW to anyone that knows the 700 and has heard that not hooking up TCC will fry the tranny, the 2004R and 700R4 both share the same fluid routing, and there are NO stories about the 200 burning up like the 700 without the TCC hooked up.

    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>
     
  12. CaptCrunch

    CaptCrunch 1/2 ton status

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    yeah 87 and up have the aux. valve body which is nice... also they have a lot of items updated.

    [​IMG]
    1987 Chevy K5 Blazer- 350 TBI
     
  13. dyeager535

    dyeager535 1 ton status Premium Member

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    Beyond what I know in 700 operation here...perhaps with just a slipping band the fluid pressure is different in 4th than 2nd, and somehow it works ok? Then again, it may be something much less complicated...I don't claim to be an expert on these things, maybe some tranny guys can help you out.

    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>
     
  14. CaptCrunch

    CaptCrunch 1/2 ton status

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    Actually I will bet 100 to 1 odds it's the classic rebuild/upgrade mistake (aka F#@kup). They modify third to shift in quicker so it doesn't burn out like they did stock. Well alot of guys out there don't modify/forget to modify 2nd to release quicker, thus it binds up... it can feel like anything from a hard shift to a complete thud depending on how it was modified. Chances are that 2nd will be fried when it goes out... I've at least never heard of GM ever having a problem w/ 2nd stock.

    Dyeager- The vette servo makes a regular 700 shift hard... the vettes had a specially design aux. valve body to prevent such a hard shift. This is a really stupid upgrade if you haven't upgraded the sprag and shell... because they just get hammered on w/ a vette servo and they are already one of the 700's weak points. I have heard the Caprice ones are a good choice... less harsh, but still give a lot better shift quality.

    [​IMG]
    1987 Chevy K5 Blazer- 350 TBI
     
  15. dyeager535

    dyeager535 1 ton status Premium Member

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    Do you know if the later 700's (87-up) ever got any hardened parts that would handle the additional vette servo "load"? I don't plan on ever running a 700 in my life again, but sometimes its nice to know this stuff. : )

    I wasn't aware of the aux. valve body, I've just heard of the vette servo being a cheap upgrade. Did they use the same servo/aux valve body since the introduction of the 700 in the vette, or was it one of those "oops, messed up" kinda learning experiences like all the early 700's?


    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>
     
  16. CaptCrunch

    CaptCrunch 1/2 ton status

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    I believe the sprag redesign was in the 85 model... Basically all the stock 700's are weak in that area. Obviously vetter 700's are a bit more performance minded. Now I ran a vette servo w/ race sprag and aftermarket shell in my old street/strip Trans am... and man did that thing shift! I'm not sure on the vette trannys... I'll ask my buddy since he is the tranny man. I do know that another friend has a 86 vette that he is getting ready for road races and it has the aux valve body. I'd guess that either 85 or 86 was the first year for it... which would of left 84 the odd man out... although the rest of the trucks and cars could of just adoped it from the vettes. I know they have a completely different valvebody and sprag. They were designed to be a bit beefier I'd guess, but probably not by much. I'm pretty sure it is like everything else GM has done... TH350, HEI, Cam/crank sensor system, 4.3 Vortecs... they are FUBR until they get the stuff worked out.
    700's are good trannys if you find a good guy to rebuild them (sometimes very very difficult). My buddy there is actually running one behind his big block (500hp) and it has lasted great so far... but then this has been nearly a 8 yr project for him... he thinks it's as good as he can get... if it blows he's gonna start playing w/ 4L80's. He generally builds stout 2wd 700's for about 1500 installed... Jet also has one on the aftermarket for that kinda $$$ and then there are a couple of very well know 700 shops around the country.

    [​IMG]
    1987 Chevy K5 Blazer- 350 TBI
     
  17. bigerik

    bigerik 1/2 ton status

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    Hey Hispanic Panic, not only is my Jimmy a very close cousin of yours, I also speak Spanish. Visit my website at <A target="_blank" HREF=http://www.bigerik.coloradoK5.com>http://www.bigerik.coloradoK5.com</A>....you'll think it's your truck, macho!
     
  18. HispanicPanic

    HispanicPanic 1/2 ton status

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    WOW !!!!!!!!!!!! and i thought i was the only one who liked orange and white i gatta say "esa si es troca no chingaderas"

    <A target="_blank" HREF=http://jimjim.coloradok5.com>http://jimjim.coloradok5.com</A> [​IMG]
     
  19. HispanicPanic

    HispanicPanic 1/2 ton status

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    well thanx guys now i know what to do....and thats stick to my th350

    <A target="_blank" HREF=http://jimjim.coloradok5.com>http://jimjim.coloradok5.com</A> [​IMG]
     

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