The 700R4 is a good transmission although it has some weak points, but if maintained properly and installed correctly, the 700R4 transmission should give you several miles of trouble free service.
My 1992 Chevy Silverado 1500 has the 700R4 transmission and it currently has 200,000 miles on it and has been going strong, but I also change the transmission fluid and filter every 20,000 miles to 30,000 miles and also have a transmission cooler that also helps and I always check the fluid level often as well.
The weakness of the 700R4 transmission is that it often tops out at around 300 to 350 horsepower and if you push the 700R4 transmission beyond that point or fail to maintain it, it exposes the 700R4 to it's common flaws which includes it's 3-4 Clutch Pack, Throttle Valve Cable, the sun reaction shell and forward sprag and pump.
Heavy duty applications or abrupt shifting with the 700R4 transmission can overload the stock forward clutch sprag and cause the front pump bushing to migrate out of place.
And the original factory sun shell of the 700R4 transmission is also relatively thin and is prone toping teeth or even snapping under high torque.
And the 3-4 clutch pack is long regarded as being the primary weak point of the 700R4 transmission as the factory setup was prone to slippage and premature wear, which leads to overheating and transmission failure.
Also the 700R4 transmission is fully hydraulic and requires and relies on the TV cable also known as the throttle valve cable to dictate shift timing and line pressure.
And if it's adjusted even slightly incorrect, it can result in harsh engagement, delayed shifting and even devastatingly low line pressure that burns out the clutches.
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.