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Old 04-09-2011, 10:08 AM
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Stacked shifts on a 700R4

86 Chevy Pickup, 454, mild cam, otherwise stock. 6-71 BDS blower. 26" tires, 4.11 rear gears. Kind of a pro-street type set up, used for cruising only, NO RACE, occasional romp through 1-2 gear. Had a TH400, wanting the OD for better road manners/lower RPMs at 60-70MPH.

OK, a 1989 700R4 that has just been rebuilt by me using a kit from Pro Built Automatics. Among other things it includes a Transgo shift kit.

The trans is stacking the light throttle shifts. It will be in OD TCC locked by 15MPH. I think it may be slipping in OD. Manually shifting, 1-2 shift is good, 2-3 shift is good, 3-4 shift is soft.

LOKAR is the only company I could find that sells a TV cable for the side throttle linkage required for the blower/carb setup. At WOT the TV cable is at full pull. But I'm not at all sure that it is correct at other throttle settings. At idle it is at minimum TV, no slack.

Line pressures;
TV cable disconnected, 1000RPM (idle)
P 75
R 130
N 75
OD 75
3 75
2 125
1 125
TV fully pulled
P 210
R 250
N 210
OD 210
3 210
2 175
1 165

Any suggestions will be appreciated.
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Old 04-09-2011, 01:58 PM
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stacked shifts usually caused by stuck or sticky governor , valve body or the TV inner valve on the valve body
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Old 04-10-2011, 07:01 AM
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Thanks for the comments Crosley, I guess the first place to look would be the governor.

I did recheck the TV setup last evening and it is adjusted correctly as far as I can tell. Is my thinking correct that a loose adjustment will/could cause early shifts and a tight adjustment would/could stretch the shifts out?
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Old 04-12-2011, 06:45 PM
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Try this disconect TV cable then try pulling the TV cable all the way out then let it snap back a few times this may free up the valve.
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Old 04-13-2011, 12:21 AM
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Yes, Loose = early/soft shifts. Tight = later/firmer shifts. You don't want any slack in the TV cable @Idle.

Try unplugging the TCC electrical plug on the Trans & see if it makes a difference in shifts. Would indicate a bad TCC Solenoid or unwanted -ground.
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Old 04-14-2011, 08:04 AM
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Well the owner called me yesterday with news. The truck shifts are stretched out more, almost normal, when the TCC is switched off. He has a switch in the cab. When the switch is in the on position, the shifts stack and the TCC locks, all by 15MPH or sooner. Also he tells me the TCC will lock in 3rd gear too. I am totally confused now.

How does the TCC circuit have anything to do with shift points???

And why id the TCC locking in third when I've got it wired through the 4th gear switch only???

ETA: this is a 1989 700R4
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Old 04-14-2011, 08:53 AM
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If the TCC Solenoid is bad/shorted or the wiring or Pressure switch is shorting out "Grounding" it can lockup in 2nd, 3rd & 4th gears.

Similar problem here>> http://www.turbobuick.com/forums/tra...lp-needed.html

More TCC Solenoid problem Info>> http://www.montecarloss.com/TCC_Solenoid.html
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Old 04-14-2011, 11:20 AM
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So what you are thinking the wiring, or 4th gear switch, or the TCC solenoid is grounded. This would cause the trans to stack shifts??? Not trying to argue, just trying to wrap my head around this.
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Old 04-14-2011, 05:36 PM
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I replied to your post on the Probuilt web site.

How exactly do you have the TV cable attached to your carburetor? What type of carburetor? Are you using a geometry corrector on the carb? Just because you have the cable adjusted such that carburetor wide open throttle equates to full TV cable pull DOES NOT MEAN THAT YOU HAVE THE TV CABLE SET CORRECTLY.

At this point, I would like to know how you have the TV cable attached to the carburetor arm... Can you post a pic?
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Old 04-14-2011, 07:43 PM
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Quote:
Originally Posted by Kawabuggy
I replied to your post on the Probuilt web site.

How exactly do you have the TV cable attached to your carburetor? What type of carburetor? Are you using a geometry corrector on the carb? Just because you have the cable adjusted such that carburetor wide open throttle equates to full TV cable pull DOES NOT MEAN THAT YOU HAVE THE TV CABLE SET CORRECTLY.

At this point, I would like to know how you have the TV cable attached to the carburetor arm... Can you post a pic?
The TV cable is not connected to the carb. This is a blower application, as stated in my original post. There is no available place, or room, for the TV cable on either carb. The cable is connected to the linkage at the base of the blower on the bell-crank that the throttle cable is connected too. It is a Lokar application for a 700R4.

I can post a picture but it will be tomorrow evening before I can get it.

As far as adjusted correctly, yeah I think it is. WOT = full pull. Idle = no slack. From the centerline of the pivot shaft, it is approximately 1 1/8" from the centerline of the connection point of the TV cable. It's hard to get an accurate measurement. But that is what it looks like.
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Old 04-15-2011, 07:47 AM
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Quote:
Originally Posted by Overdriv
So what you are thinking the wiring, or 4th gear switch, or the TCC solenoid is grounded. This would cause the trans to stack shifts??? Not trying to argue, just trying to wrap my head around this.
Yes, it can cause stacked shifts. You would have to study the Fluid paths to understand how/why. If you could find a GM 700R4 Principles of Operation manual it has all the diagrams.
This is from a 2004R P of O manual & has the same setup as the 700R4:
http://www.turbobuick.com/forums/tra...-tutorial.html

Your description of the TV cable's setup above sounds correct. The distance from Center of Throttle Shaft. The Angle also needs to be correct for adequate line pressure rise.
Diagram here:
http://www.tciauto.com/Products/Inst...ble_adjust.htm
More Info:
http://purplesagetradingpost.com/sum...o/700R4p1.html
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Old 04-15-2011, 12:34 PM
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From PATC's site:
Looking at the throttle shaft lever from the left side at idle position, 33% of the throttle lever total travel must be to the rear of the throttle shaft centerline. And at wide-open throttle, 67% to the front of the throttle shaft centerline. This will be about -inch to the rear and 1 inch to the front of the throttle shaft centerline.

The throttle valve cable must be hooked up in this manner so the pressure will rise faster off idle and slow down at heavy throttle. If the pressure cable is pulled in a more even manner the pressure will be too low at light throttle. Failure to hook-up the throttle cable in this way will burn the three-four clutch pack up fast.
http://www.transmissioncenter.net/Full.jpg
http://www.transmissioncenter.net/Idle.jpg
http://www.transmissioncenter.net/Setup.jpg
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Old 04-15-2011, 01:09 PM
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Ssedan, that is great info, thanks so much. I did not know it worked like that. The books I have do not describe it in as much detail. Thanks a lot!

Here are some pictures of the TV setup. From the pictures from the Transmission center it looks like we might be starting to far back.

Thanks again for the information guys. The info from the Buick forum is very enlightening.
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Last edited by Overdriv; 04-15-2011 at 01:24 PM.
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Old 04-15-2011, 01:19 PM
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I think we can make the necessary changes to the geometry of the arm to make it right. But I do believe it is starting to far to the rear. It ends up just a bit forward past 90* at WOT. Just about opposite of what it should be.

We will make some adjustments before he drives it again.
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Old 04-15-2011, 07:12 PM
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Please post back after you get the geometry for the cable worked out and let us know if that fixed it. People searching this site can find the information later and hopefully save them some headaches..
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