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#1
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700r4.. no 4th gear?
this past summer i installed a 700r4 along with my 89 corvette 350. i turned it into carb. i need help to use the 4th gear. can i drive iut like this? i mean to be honest i have been and its been driving nice. just no 4th gear, is this bad for my tranny? what kit should i install if i dont want a kit tapped into my brake pressure system??? thanks,, any help would be appreciated!
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#2
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Cool 'ol Chebby.
Do you know your rear end gear ratio? How fast have you had it? Sometimes 4th can't possibly happen due to a governor/ TV cable mis-calibration. |
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#3
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from the research ive done like 700r4.com etc. my tv cable is adjusted right. i just go on different forums and i hear dofferent stuff, like i need to buy a kit which will automatically run the 4th gear when on the highway and then when brakes applied will shut off,, or shall i say "lockup"?????
i heard another forum where he ran power from the tranny, and when on the highway hit a switch meaning he turned on the lock up. and then when reducing he turned off?? i tried that one but i dont think it worked. |
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#4
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Yeah, lockup and 4th gear are two vastly different things. Not sure which you are really 'feeling'. Lockup on a TH700R4 is simply a switched +12v to pin 'A'. on the trans plug. (front outer pin)
If your '50 has a sky-high rear end ratio, your new trans may not shift into 4th until warp speed. For example, the donor car had vastly lower (higher numerically) rear end ratio and your car has a higher rear end ratio (lower numerically)... |
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#5
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As C10 mentioned, lockup is a function of the convertor, and if you are not supplying power to the TCC (torque covertor clutch) it'll sure feel like you have no 4th gear, when, in reality, you've got all gears but cannot realize the full .67 ratio of 4th due to the convertor "slipping". The lockup clutch makes a full mechanical connection in the convertor , thus rendering full overdrive. My Caprice originally had 305/700R4, and when I had a 383 put in and the trans beefed, the disconnection of the ECM of the 305 caused no power to be fed to the TCC (which on this particular application, 305/700R4/2.54:1 open) had been triggered off 2nd thru 4th gears. As a result, I also had no lockup occuring when I got the car back (now with 3.08 posi). Needless to say it felt like no 4th gear, so we manually wired thru switch on dash and retained use of brakelight switch for disengagement. Due to time constraints of being in the middle of a 700 mile move, I actually towed a trailer from Chicago area to Gadsden,Al. without the lockup and got a whopping 7 mpg! (Outclimbed ALL the bigrigs thru the steeper uphill grades of TN. and AL. mountains though!) Anyway, some 700R4's were triggered from 2nd gear, some from 3rd, some from 4th only. While there are kits available for TCC lockup, I believe you can find manual wiring instructions on this site thru the knowledge base. Do a search for it and I'm sure it should come up. Good luck and happy rodding.-Jim
Jim the 700R4's 4th gear is .70, the 2004R's 4th is .67 Correction 9/23/08- Oops,My bad!!! -Jim Last edited by j.d.brown.042964 : 09-23-2008 at 10:01 PM. |
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#6
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Jim the 700R4's 4th gear is .70, the 2004R's 4th is .67
Daoriginator64 There're many ways to wire up the TCC solenoid as Jim mentioned above. From using just a toggle switch to using Brake, Vacuum and Pressure switches. Here's a few I have saved. http://www.chevyasylum.com/tech/4thgear.html http://img45.imageshack.us/my.php?image=yo5la.jpg http://www.73-87.com/7387garage/drivetrain/lockup.htm TV cable & Carb linkage geometry & TCC solenoid http://purplesagetradingpost.com/su...fo/700R4p1.html This shows & explains the what/why of signals the 4pin trans connector will use on cars with computer etc.. http://www.turbobuick.com/forums/tr...trans-plug.html This show a simple toggle diagram. http://www.montecarloss.com/communi...&gonew=1#UNREAD |
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#7
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that first wiring example seems easiest what are the negatives and positive of going that route? i wont be towing anything, i just want it to be realiable, and last, im afraid the way im going that im going to burn this tranny.
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#8
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Quote:
Do you have the correct TV cable geometry corrector for your Holley carb? The last link from the MonteSS site shows the toggle switch method. They used a Relay also. You would just leave it switched off unless you are cruising in 4th on freeway etc.. http://cgi.ebay.com/ebaymotors/700R...1QQcmdZViewItem Last edited by SSedan64 : 09-24-2008 at 03:31 AM. |
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#9
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Jim the 700R4's 4th gear is .70, the 2004R's 4th is .67
Sorry for my dyslexic fruedian slip on 4th ratio. I stand corrected.-Jim |
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