To make a 700R4 transmission shift harder, you will need to fine tune the TV cable, which is also known as the Throttle Valve cable or even install a shift kit.
Having a tighter TV cable raises the internal line pressure on the 700R4 transmission for firmer shifts and internal kits physically alter the fluid routing for quicker and more aggressive clutch engagement.
The 700R4 transmission relies entirely on the TV cable to dictate the line pressure and so increasing the tension on the TV cable, forces the 700R4 transmission to run at higher pressures, which results in a firmer and more positive shift.
To adjust the TV cable, with the engine off, press the release button on the TV cable bracket and then push the cable housing all the way back toward the firewall.
Next firmly push the throttle linkage to wide open throttle to allow the cable to ratchet out to it's exact setting.
For a harder shift, you can manually adjust the TV cable by clicking it 1 to 2 notches tighter so that it pulls the throttle valve slightly earlier than factor spec.
Just don't overtighten the TV cable drastically, just to get an aggressive shift, because it can cause the 700R4 transmission to run too hot and lead to internal damage.
A 700R4 transmission will also not shift properly without the TV cable and will burn up the very quickly.
Driving without the TV cable on the 700R4 transmission will cause the transmission to have early and weak shifts and severe slipping, which will quickly destroy the 700R4 transmission in a matter of a few miles or less.
The TV cable is required for the 700R4 transmission to shift properly as the TV cable mechanically regulates the internal hydraulic line pressure that is based on the throttle position.
Unlike older transmissions that use engine vacuum, the 700R4 transmission relies on the TV cable to determine how much line pressure is needed and more throttle = more pressure and less throttle = less pressure.
Without the TV cable indicating throttle position, the 700R4 transmission will not known when to command the shifts and result in erratic and extremely early shifts and no passing gear.
And low line pressure that is caused by a disconnected or loose cable allows the internal clutches and bands in the 700R4 transmission to slip, which creates immense heat and rapidly burns the transmission up.
The only way that you can operate a 700R4 transmission without a standard TV cable is if you install a specialized Constant Pressure Valve Body or a Constant Pressure System such as those from TCI, which are aftermarket modifications that allow your transmission to maintain adequate line pressure without a cable, although the shift timing might still require being managed manually.
The common problems that the 700R4 transmission have are delayed shifting or hard shifting as well as slipping gears and sometimes total transmission failure.
These common issues with the 700R4 transmission, which was later known as the 4L60 transmission are often caused by fluid loss, inadequate cooling and even a misadjusted Throttle valve cable also known as the TV cable.
The 700R4 transmissions TV cable or throttle valve cable is what determines the transmission line pressure that is based on the engine load.
If the transmission TV cable is stretched or misadjusted or is installed with the wrong geometry on aftermarket carburetors, the 700R4 transmission will burn up the internal clutches very quickly and so it's important to make sure the TV cable for the 700R4 transmission is adjusted correctly and installed correctly.
Ensure that the TV or transmission valve cable is properly calibrated using the manufacturer's specified procedure to align the throttle position with the transmission line pressure.
The slipping gears and momentary surging that can occur with the 700R4 transmission is a common issue with the 700R4 transmission and includes, slipping, especially when the transmission is cold, or a failure to shift into 2nd or 3rd gear and often points to low transmission fluid or a clogged filter.
The fluid loss with the 700R4 transmission often occurs at the torque converter seal or tailshaft seal.
You should check the transmission fluid on level ground while the engine is running and warm and top it off and replace any leaking seals.
Loss of reverse gear and overheating are also common with the 700R4 transmission, especially when not maintained properly or when you do a lot of towing.
Losing reverse or having difficulty in engaging into neutral is a widespread issue with the 700R4 transmission that stems from internal wear, worn reverse clutches or low fluid pressure due to case leaks.
You should inspect the tailshaft for leaks and verify fluid levels, if the fluid is full, the transmission may require a teardown to inspect and replace the worn reverse bands or clutches.
And operating a 700R4 transmission without an adequate transmission cooler frequently leads to burnt fluid and warped internal components.
And so you should ensure your factory transmission cooler is fully functional and consider installing an auxiliary transmission cooler if you use the vehicle for towing or heavy duty hauling.
However, while there are some common issues with the 700R4 transmission, it can be a very reliable transmission if maintained properly and you change the fluid and filter often enough as well as ensure the fluid level doesn't stay low and you don't overheat the transmission or overload it.