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new motor now hard shifts

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by MNorby, Apr 12, 2002.

  1. MNorby

    MNorby 3/4 ton status Premium Member GMOTM Winner

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    I put a 400 sbc from a '76 chevy in my '86 last week and ever since then she shifts really hard. It has a 700R4 tranny. Last night I put the old carb off the 305 on it since it has all teh electrical stuff on it but it still shifts hard and now has no power. I think I might as well put the original carb back on it but why does it shift so hard and doesn't want to shift till it reaches 4000 rpm even if you are at 1/2 throttle? I found 2 wires that I can' figure out where they go. One looks like it comes from the tranny and splits about by the driverside exhaust manifold next to the firwall and one lead goes and and looks like into the cab and I don't know where the other one goes but it has a connections for a 2 wire plug on it. If need by I can take pics this weekend to show. The other wire is on the pass side of motor on intake manifold and has a 2 wire connectio that looks like it goes inline with something. I can take pics of it too. Remember the 305 used to have all teh smog crap at one time and I am wondering if some wires are for the air pump or something but that was removed before I bought the truck. Any ideas? Thanks
     
  2. MUDNUTT

    MUDNUTT 1/2 ton status

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    did you hook the t.v. cable back up? the tranny wont shift right without it.

    deck
     
  3. ramjet gmc

    ramjet gmc CK5 Staff Staff Member Moderator GMOTM Winner

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    That’s what I was leaning to also the t.v. Cable and do you have a locking tork converter?
    Keep us posted /forums/images/icons/smile.gif
     
  4. Blazer_Boy

    Blazer_Boy 1/2 ton status

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    Ditto on the TV cable thingy. Just go to google and type in TV cable adjustment. All it does is regulates transmission pressure based on throttle position. The wires you are talking about are for the toque convertor. Normally your torque convertor slips, so your motor is turning faster than your transmission. This unit allows you to idle while not having the transmission moving so you won't stall the motor. When you get enough RPMs, the convertor catches and delivers power to the transmission, the stall speed as its known. What those wires do is make the torque convertor lock up on the highway. With a 1:1 of engine revolutions to transmission, you now have lower RPMS and better mileage. There should be a little vaccum switch on the upper right side of the firewall. You may also have one on the left, thats just extrianeous crap that you don't need. The one on the right gets suction from the carb at higway conditions and tells the convertor to lock up. Make sure you have all the electrical garbage hooked up or the carb will be goofy. If I were you, I'd drop the distributor you have for something older and get an '81-'84 ish carb that has a port for the lock up convertor but without all that electronic crap.
     
  5. riz

    riz 3/4 ton status

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    <font color=blue> Adjust your TV cable ........ I had the same problem when I dropped in my new engine ! Also, your tranny will burn up if the TV cable isn't adjusted properly.
     
  6. MNorby

    MNorby 3/4 ton status Premium Member GMOTM Winner

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    how do you adjust it. I hooked it up but I don't know how to adjust it and how do you know were to adjust to unless it is trial and error? Does it adjust by the carb or by the tranny? Thanks for the quick replies too /forums/images/icons/smile.gif
     
  7. MNorby

    MNorby 3/4 ton status Premium Member GMOTM Winner

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    These steps look kosher? I think I answered my previous question.

    1. Remove air cleaner on vehicles with carb. or TBI.

    2. Depress lock tab down on TV cable and push cable all the way Forward towards carb. or injector.

    3. Have someone sit in vehicle and depress gas pedal to the floor so it's at WOT (Wide Open Throttle). Hold it there for steps 4 and 5.

    4. Now check to make sure the carb arm is bottomed out or has no more movement. If not, use a pair of Channel Locks to bend TV cable bracket until carb. or injector arm no longer rotates.

    5. Next, depress lock tap down and pull TV cable back (Pull HARD!) towards firewall or away from carb or injector untill it stops and than release the tab.

    6. Use a pocket knife or hacksaw blade to mark the cable in front of the snout. This is MAX TV.

    7. After marking Max. TV depress lock tab and push cable forward toward carb. or injector 1/8'' of an inch. Make a mark in front of snout. This is Minimum TV.

    8. Set cable back to Max. TV and Road Test.
     
  8. MNorby

    MNorby 3/4 ton status Premium Member GMOTM Winner

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    another ? now. Since it is probably the TV cable problem I might as well put the original carb back on the motor . It seemed to run better with it but it doesn't have the electric connections to it and it isn't electric choke (big deal though /forums/images/icons/wink.gif) Is there any reason I need the electrical stuff with this motor? Both carbs are original quadrajets
     
  9. 6.2Blazer

    6.2Blazer 1/2 ton status

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    From my understanding you will also need to make sure you have the lock-up feature of the torque converter functioning or it could lead to early failure of the trans.
     
  10. MNorby

    MNorby 3/4 ton status Premium Member GMOTM Winner

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    sorry for being dumb but how would you know if it is a lockup converter? Would that be the 2 prong wire that I noted about that I don't know were it goes? If it were that wire were does that plug into?
     
  11. MNorby

    MNorby 3/4 ton status Premium Member GMOTM Winner

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    I'm detemined to beat this thing. Anyways, I did the adjustment and found it was already as far back towards the firewall as it can go. I pushed the button and pushed back and futher then floored teh gas pedel and nothing happened or moved. I drove to twn and it was like it was. In town I pushed it forawer toward the radiator about 3/16th of an inch or so and tried that and it maye have done a little help but not a whole lot. Should I move it forward more or am I doing it worse that way?
     
  12. dyeager535

    dyeager535 1 ton status Premium Member

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    Sounds to me like the TV cable is too tight. Too loose and you typically end up with sloppy slipping shifts.

    The 700 is going to have a locking converter. The plug is on the drivers side of the transmission. It most definitely heats the tranny up without being hooked up, and without auxiallary cooling, it can potentially cook the tranny.
     
  13. Blue85

    Blue85 Troll Premium Member

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    If it's an 86 and an auto, it's a TH-700R-4 with a lock-up torque converter. Make sure you get the electrical connected or it can't lock up (some may argue, but they are wrong /forums/images/icons/smile.gif ). The most important thing is that it has the wire that is always hot connected to it. That will at least give you lock up in O/D so you won't have to sing "Clutches roasting on an open road". Then you need to get those plugs connected to the vacuum switches.

    One plug should go to a vacuum switch that is mounted to your firewall over by the brake booster. That is what gives you lock up based on ported vacuum. If your carb doesn't have that port, then just skip it and go with lock up only in 4th gear or get a speed sensing lock up controller.

    The other plug should go to a vacumm switch mounted on or near the passenger side valve cover. This is to allow the EGR to get vacuum only when you are at cruising speed. If your new engine doesn't have EGR, or has EGR hooked up a different way already, just skip this plug.

    But make sure you get power to the tranny and until you do, don't use O/D.
     
  14. MNorby

    MNorby 3/4 ton status Premium Member GMOTM Winner

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    I have an aux tranny cooler. I think I know the wire for the locked I think but it isn't connected up in the motor area but is connected on the tranny. Where in the motor compartment hook up to? The wire I am looking at anyway is a 2 wire group and the end is flat connection with 2 female plugs but I can't figure were it plugs into. I have a vacuum hooked from a little cylinder on teh firewall going to a connection between the carb and distributor. Also is there a way to know or feel if it is TC is locking up? I don't think I who what to do to see if it is
     
  15. dyeager535

    dyeager535 1 ton status Premium Member

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    Well, Blue85 covered it. The TCC plug on the tranny is a 4 prong square, with typically three wires. (which depends on application) Yours sounds more like the alternator, AC, or AIR plug, perhaps a mix control wire for the carb. I *think* a mix plug on the truck would be blue, as is the connector on the carb.

    Only way to know if lockup is happening is be on a very smooth road, put it in 3rd, accelerate pretty slowly to around 45MPH, and "feel" for all the gear shifts. You'll have 1-2, then 2-3, then a (typically) very soft one in 3rd, shortly after it shifts, if you aren't on the gas much.

    If you have a tach, you can watch instead of feel, for the same thing, or when cruising in 3rd or OD, keep foot on gas, and lightly tap the brake pedal, and see if the RPM's jump around 250-500RPM's.
     
  16. MNorby

    MNorby 3/4 ton status Premium Member GMOTM Winner

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    ok. I think I am starting to understand this. Thaks for al lthe help thus far. Basically after it droppes into 4th (OD) then a second later is drops rpm by a few hundred that is the lockup? I am confused, will it do that in 3rd also? I remember it doing that before but I don't recal if it is doing it now, I'll check after work. If it isn't locking up am I safe to drive it w/o using OD just keep in in 3rd max or should I shut her down till I get it fixed?
     
  17. dyeager535

    dyeager535 1 ton status Premium Member

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    Yes it should do it in 3rd.

    I believe the concern with having it in OD with no lockup is the two (in the 700?) OD frictions. If you can keep the tranny cool, and line pressure is high, then it's no different than driving it in OD with lockup functioning, since lockup isn't ALWAYS used when in 3rd/4th gear...thats why there is a vacuum switch.
     
  18. MNorby

    MNorby 3/4 ton status Premium Member GMOTM Winner

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    I went and checked again. The wiring is hooked to the tranmission. it make a split then one set of a blue and yellow wire goes off and I don'tt know where it connects. Another set goes up and make another split. One set of 2 greens (?) and a blue which then connect to a vacuum line behind the brake master cylinder on the firewall and that vacuum goes around and plugs into the carb in a T that also goes to the vacuum advance. Another set of 2 wires goes off the vcuum set and they are blue and green and the blue is butt connected to a brown wire wich goes into the cab and the green wire has a connection on it but nothing is connected to it. I am guessing the last ones are the brake wire (?) and the unconnected one may be for the cruise control that never has worked (just guessing now remember). I am guesssing teh ones that goes to the vacuum is what tells it to lock up and the first wires I talked about I have no clue where they go. Hope that may give you a visual. I have a drawing I made but I won't be able to scan it till I get him late tonight. Thanks for all the great help
     
  19. dyeager535

    dyeager535 1 ton status Premium Member

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    Someone obviously messed the wiring up. I hate that. I wouldn't imagine there is supposed to be many, if any, splices in the TCC wiring. It needs temp input, VSS, and vacuum to lock up, and if it has TPS on the carb (drivers side) it needs that too. Not much point in vacuum with TPS though, so likely one or the other.

    Since I haven't dealt with the later trucks wiring wise, I am getting out of my league on this one, and I really wouldn't know what is supposed to be where. But just test lockup and see if it works. If all you changed is the motor, it's pretty much a certainty that the TV cable is going to be the cause of the hard shifting IMO, and have nothing to do with the lockup working or not.
     
  20. MNorby

    MNorby 3/4 ton status Premium Member GMOTM Winner

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    Ya, I haven't tested to see if it locking up. I guess the big thing at this time is the TV cable. It was all the way back from the get go and I did the "steps" to adjust it but it stayed all teh way back. I did move it forward about 3/16- 1/4 inch and I think it did soften it but how far is too far to come forward with the adjuster so I don't get the change to sing "cluth packs roasting on an open road" /forums/images/icons/wink.gif ?
     

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