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My truck is rediculous to drive on the freeway...advise?!?!

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by heavy4x4, Nov 23, 2003.

  1. heavy4x4

    heavy4x4 1/2 ton status

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    Alright guys, I just got back from a 4 hour drive on the interstate (I was in Northern Wisconsin deer hunting). Anyway, I HATE how my truck drives on the interstate. My truck sucks when it's windy or going up a grade (it's okay on a flat stretch of road with no wind).

    Here's the deal. In order to get my beast to go over 65, I have to push the gas to the point where it will shift out of lockup. It's like the gas isn't depressed enough to make my truck go 65 in lockup, so in order to go over 65, it has to be unlocked. I don't want to be running not in lockup because my tranny gets hot (I've got a temp gauge, and when it's not in lockup, I can literraly watch the needle climb). And, today there was a wicked head-wind, and my truck was nearly impossible to keep at a constant speed. Most of the time I was under 65 and it was going from OD-lockup, to OD-unlocked, to Drive, and all over again. /forums/images/graemlins/angryfire.gif Also, in order to get it to lockup again after it has unlocked and I'm going about 70, I have to back the throttle almost all the way out, and by that time, I've slowed down to the point that I need to gas it again to get back up to speed and then I'm not in lockup...back at square one.

    Anybody else have this problem? I'm running 33's, 3.73's and a 700R4. It is fairly close to the stock setup, gear-wise, but it sure doesn't drive like it. I think my problem would be solved if I could get the tranny not to unlock at the throttle position that it does. It feels like there is still plenty of power at the RPMs it runs at in OD lockup, but the tranny wants to kick it out of lockup any time I barely touch the throttle.

    Now for my question, I guess. Is the locking/unlocking a function of the TV cable at all? I'm thinking maybe I just need to adjust my TV cable again and that will change the point the tranny unlocks...maybe not. I know the 700R4 has a valve in it that will unlock the torque convertor when the throttle is at 2/3 of full throttle. I'm almost positive I'm not that far down.

    Sorry if any of this is just a rambling mess, but I'm kinda pissed right now...I did this whole axle swap to different gears in hopes of solving this problem, but it's still there. I'd rather not burn up my tranny, which is going to happen if this keeps going on. And, I am positive lower gears wouldn't help, because I'd have to push the gas down even further than now to go 65, and the tranny would surely be unlocked the whole time then.

    /forums/images/graemlins/confused.gif What can I do?
     
  2. Bubba Ray Boudreaux

    Bubba Ray Boudreaux 1 ton status

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    [ QUOTE ]
    Anybody else have this problem? I'm running 33's, 3.73's and a 700R4.

    [/ QUOTE ]

    That's your problem right there, you are undergeared for anything more than flatland............................
    /forums/images/graemlins/deal.gif /forums/images/graemlins/deal.gif /forums/images/graemlins/deal.gif
     
  3. SUBFAN

    SUBFAN 1/2 ton status

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    Strong headwind, OD, and 65 mph? Put that sucker in Drive during those conditions. You are not giving the truck enough mechanical leverage for that situation.

    If you think the R's are to high, just back off 5 mph....
     
  4. 99firehawk

    99firehawk 1/2 ton status

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    you need one of these

    700R4 full throttle 3-4 up-shift sleeve. Now you can have a full throttle 3-4 shift. At 80 MPH it takes 90% throttle to make a 4-3 downshift. Can be installed without removing the valve body. The Up-shift Sleeve also eliminates part throttle 4-3 downshift for less gear searching. This is an extra option on the 700 Raptor. Not recommended for motors over 250 horse power. Cost $49.00

    http://www.transmissioncenter.net/highperf700r4.htm#700R4%20Parts
     
  5. heavy4x4

    heavy4x4 1/2 ton status

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    In D-lockup, I'm running about 3 grand at 65...that's too much IMO for an extended length of time.
     
  6. heavy4x4

    heavy4x4 1/2 ton status

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    [ QUOTE ]
    [ QUOTE ]
    Anybody else have this problem? I'm running 33's, 3.73's and a 700R4.

    [/ QUOTE ]

    That's your problem right there, you are undergeared for anything more than flatland............................
    /forums/images/graemlins/deal.gif /forums/images/graemlins/deal.gif /forums/images/graemlins/deal.gif

    [/ QUOTE ]

    I don't think so though. Like I said above, if I had 4.10's or 4.56's, I'd have to have the throttle pushed down even further to go 65 than I do now, and the torque convertor would unlock. /forums/images/graemlins/crazy.gif
     
  7. bryguy00b

    bryguy00b 3/4 ton status

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    hah...i dunno..i have 3.08 and 33's and i would have a hard time getting my truck over 3 grand, i usually have only ever had it up to 2500 or so /forums/images/graemlins/rotfl.gif
     
  8. Bubba Ray Boudreaux

    Bubba Ray Boudreaux 1 ton status

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    [ QUOTE ]
    [ QUOTE ]
    [ QUOTE ]
    Anybody else have this problem? I'm running 33's, 3.73's and a 700R4.

    [/ QUOTE ]

    That's your problem right there, you are undergeared for anything more than flatland............................
    /forums/images/graemlins/deal.gif /forums/images/graemlins/deal.gif /forums/images/graemlins/deal.gif

    [/ QUOTE ]

    I don't think so though. Like I said above, if I had 4.10's or 4.56's, I'd have to have the throttle pushed down even further to go 65 than I do now, and the torque convertor would unlock. /forums/images/graemlins/crazy.gif

    [/ QUOTE ]

    I can guarantee ya that is your problem. I ran that setup for a few years and having to drive over the mountains out here, while not as bad as the 3.73/35" setup, was almost as bad. The deeper gears give you the torque multiplication that you need to get over those hills and through the wind.............. /forums/images/graemlins/smirk.gif
     
  9. 84_Chevy_K10

    84_Chevy_K10 Banned

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    [ QUOTE ]
    In D-lockup, I'm running about 3 grand at 65...that's too much IMO for an extended length of time.

    [/ QUOTE ]

    1. My '87 C30 has turned 3,000 RPM @ 65 MPH since it was new, that's how GM geared it.

    2. You're definitely under geared. 3.73 is bare minimum for 33s. 4.10s would be the minimum I'd run.

    I ran 4.10s and 35s and ran into the same problem you have. I realized I had two choices, lower gears, or ditch the overdrive. I did the latter...but going with lower gears would have been just as good of an option.

    With the lower gears, your foot will not be closer to the floor, it'll be further up. My '87 that has 4.10s, no O/D and 30" or so tall tires requires hardly any pedal at all to get going and maintain speed, even with a load, and it still gets 14 MPG empty.

    In short, the reason your freeway performance sucks is that you're trying to push a brick through the air and your engine just doesn't have enough power at that low cruise RPM to pull itself. Try lower gears or shorter tires and you'll definitely enjoy your freeway performance.

    I'd go to 4.88 if you're gonna change the gears, and consider 5.13s.
     
  10. Derf00

    Derf00 1/2 ton status

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    [ QUOTE ]
    I can guarantee ya that is your problem. I ran that setup for a few years and having to drive over the mountains out here, while not as bad as the 3.73/35" setup, was almost as bad. The deeper gears give you the torque multiplication that you need to get over those hills and through the wind..............


    [/ QUOTE ]

    I had the same set-up with the same results. Lower gears or more engine would solve your problem.
     
  11. heavy4x4

    heavy4x4 1/2 ton status

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    Well, crap. Looks like I'm screwed. Should've gone with 4.10's like I had wanted I guess. Ah well, I guess my truck will just be a dog on the freeway until I can afford to step up to 4.10's or 4.56's - hope that happens before I blow apart my tranny.

    Any tranny gurus know if torque-convertor unlocking has anything to do with the TV cable. I'm pretty sure it doesn't, but maybe with a little adjustment, I can fudge with the point it unlocks.
     
  12. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Nope. Torque converter clutch is on a vacuum switch on the firewall by the wiper motor. TV cable has nothing to do with TCC lockup unfortunately.

    When I had that setup, I had considered two options:

    1. use a vacuum switch that opened at a lower vacuum setting (so I would have to step on it more for it to come unlocked)

    2. Putting a switch under the dash to bypass the vacuum switch and force lockup.

    If I'd kept my 700, that's what I would have done. Now I just let the clutch out. /forums/images/graemlins/thumb.gif /forums/images/graemlins/rotfl.gif
     
  13. SS66

    SS66 1/2 ton status

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    Hey heavy4x4, where were you hunting? I was up in Tomahawk..about an hour North of Wasau. God the weather sucked
     
  14. SUBFAN

    SUBFAN 1/2 ton status

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    Your 'Burb will run all day long at 3,000 RPM's....

    I am putting 4.56's into my Burb to combat some of the things you are complaining about.

    Bui;ding a torquier 383 will help alot in this area too....
     
  15. moneypit

    moneypit 1/2 ton status

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    I have a toggle switch on mine.Switch it when I want it locked or unlocked. Works well.
     
  16. heavy4x4

    heavy4x4 1/2 ton status

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    I was up an hour north of Green Bay in the Crivitz/Marinette area. Yeah, the weather today sucked, but not as much as the lack of deer. My brother shot a nice 8 point opening morning, but I didn't see anything in the 16 hours I spent on stand.
     
  17. heavy4x4

    heavy4x4 1/2 ton status

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    Yeah, it'll run at that RPM, but I prefer not to be able to hear the gas flowing into the engine. I'm getting 10-11 mpg as it is. /forums/images/graemlins/rotfl.gif /forums/images/graemlins/rotfl.gif

    Also, that's wear and tear my 165,000 stocker doesn't need.
     
  18. heavy4x4

    heavy4x4 1/2 ton status

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    Can you please explain how you have yours hooked up. Is yours just a switch that cuts out the electrical connection to the tranny when you don't want it to lock, and connects it to have normal lockup functioning?

    /forums/images/graemlins/thinking.gifWhat I'd really like to do (but don't know if it's possible) is to have two switches. One would do like I said above - enable the lockup to act as it did from the factory when switched one way, and the switch flipped the other way would turn off the lockup function and turn it over to a manual switch operated by me. Here's a "for instance": I have the one switch turned on allowing the lockup to function normally for around town driving or whenever someone else drives my truck. Then, when I go on the interstate, I would flip that switch and use the other switch to manually turn on or off the lockup (not turn on or off the ability to lockup, but actually lock it and unlock it as the switch is flipped...make sense?)

    Anybody done this or know if it's possible? /forums/images/graemlins/ears.gif I'm gonna check out some wiring diagrams and see if it is a feasible option.
     
  19. jekbrown

    jekbrown I am CK5 Premium Member GMOTM Winner Author

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    [ QUOTE ]
    I ran that setup for a few years and having to drive over the mountains out here

    [/ QUOTE ]

    there aint no stinkin mountains in oklahoma! lol!! /forums/images/graemlins/rotfl.gif

    j
     
  20. 84_Chevy_K10

    84_Chevy_K10 Banned

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    [ QUOTE ]
    Yeah, it'll run at that RPM, but I prefer not to be able to hear the gas flowing into the engine. I'm getting 10-11 mpg as it is. /forums/images/graemlins/rotfl.gif /forums/images/graemlins/rotfl.gif

    Also, that's wear and tear my 165,000 stocker doesn't need.

    [/ QUOTE ]

    I disagree. You'll get better mileage by not lugging your engine down. My TBI powered 1 ton gets 14 mpg empty and it has 160,000 miles on it.
     

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