yokedworkoutbro3

Hey guys im wondering how to adjust the cable going to the overdrive from the throttle linkage. 1985 corvette 4+3 (a late 1985 i believe, has the o/d button on the shifter). Is this a kickdown cable or does it adjust pressure per throttle input? Or??
When i recently bought the car, the cable was loose in the throttle linkage. (cable sticks out about an inch past the clip)
It will not properly adjust. I can tighten the cable up, but when i push the gas pedal to the floor it just gets loose again.
My o/d isnt working and i think this could be a possible cause.
I have the trans pan off now, and this cable has an adjustment bolt on the arm that is on the bottom of the valve body. Does anyone know how this should be adjusted?? Any help would be greatly appreciated.
Ive talked to Brian at SK speed a couple times, but the past few days i havent been able to reach him...

gerardvg

It controls your auto transmission pressure, when the accelerator pedal is to the floor it makes the transmission run at higher pressure and shifts will feel a bit firmer. If it is not adjusted correctly you can fry the transmission from excessive slipping.
Best way to check is open the throttle fully and adjust the cable till there is no slack on the cable with full throttle (use the D shape button to adjust cable) It is usually a set and forget as it adjusts itself but i always check for any play in the cable.

Perhaps the teeth on your T/V cable adjuster are worn allowing it to slip and go out of adjustment. Don't drive your car if you feel it is slipping .... maybe get a new TV cable assy if it continually slips.

rodj

Step # 28
http://www.corvetteactioncenter.com/...Overdrive+Unit

But appears you need a factory gauge tool to set it up

Manual 4+3 trans can be driven no problem with the O/d not working; no different than driving it with O/d not engaged

yokedworkoutbro3

The TV cable adjuster on top of the engine seems to work fine, the button works and the teeth will hold it in place.
But when i push the pedal to the floor the adjuster slides out and causes slack again, i cant keep readjusting it, thats why i think it should be adjusted in the trans pan.
Step 28 looks to be the correct information for what i need to do, since that is the adjustment im talking about..
Im not sure what he means by "set the hook" or steps on the "guage" though...

rodj

Adjusting in the trans will do no good if the cable will not lock in position at TB.
The 4+3 cable has not been available new for some time now ; used only
or fit a later model 4+3 valve body that did away with the cable
Brian may have one

yokedworkoutbro3

The cable locks into position just fine at the throttle body, the teeth are all in good shape.
The tv cable runs out of cable before the throttle can be fully opened, causing the throttle linkage to yank the adjustment forward when i put the pedal to the floor. (this is how it is supposed to adjust). But when i let off the pedal and the linkage returns to its resting position, the cable is out too far (the crimp on the cable is about an inch past the black clip that it should be resting on). I think i just need to give it more cable from underneath, just dont want to make any changes without knowing exactly how to adjust the arm on the trans valve body.

coupeguy2001

are you talking auto trans? or stick shift trans?
you originally said 4+3.

The kick down cable on the stick trans does nothing except insure that the overdrive goes off under full throttle.

If the spring loaded arm in the trans goes back to normal, normal is "overdrive on" position.

I have a 4+3 in my 57 chevy truck, and I talked to one of the original engineers a few year back, and he said the reason they eliminated the kickdown cable in 1986 was that the throttle position sensor, in conjunction with new software in the engine computer chip eliminated the need for the cable.
He told me to take the cable out, and plug the hole in the trans case.
That means that you have to turn off the overdrive when you floor the engine.
SO, it is understood that if you have an 85, you have a stand alone year for ECM applications, and you cannot use the later computer.

If you have the pan off, you need to look at the wire that goes to the round flat device in the trans, and put 12 volts to the wire. that is the solenoid. Listen for the solenoid to engage.
You also need to check the pressure switch that is the smaller round switch with the black plastic cover that looks like a ford stop light switch. You need to find a way to pressurize that switch and check it with an ohm meter to see that it is working.

If you have the car back together, you can try a few things.

1. fill the trans overdrive with fluid.
2. jack up the rear of the car, so that the rear wheels are in the air. start the car, get it in 2nd or 3rd, and flip on the overdrive, and watch the speedometer. If the speed jumps up about 25 mph, the overdrive works, but if it does not work on the road, the clutches are worn and cannot push the car.
If nothing happens, you may not be getting volts to the solenoid.
3. rig up a switch that you can control inside the car. hook one end of the switch to the battery positive, and hook the other end to the blade connector on the left side of the overdrive.
Get the car back on jacks, get the car in second gear again, and flip the switch. watch the speedometer again, and if the speedometer jumps this time, you are not getting volts through the normal route.
If you get nothing, no change, it is possible that the overdrive pressure switch could be bad, or the solenoid is not working.
4. If you checked the solenoid and switch, you need an overhaul of the overdrive. There is a few pieces inside that will prevent it from operating, and it is bound up near the sprague clutch , or the pump has low output.