The 700R4 transmission has been in production by General Motors since the 1980s and was designed for trucks and larger cars. This transmission has been used in vehicles like the Chevrolet Blazer, Corvette, Camaro, and Impala. This model was in production for approximately ten years before it was renamed the 4L60 and then finally upgraded to be electronically controlled rather than hydraulically controlled, giving it an “E” (4L60E) which you can read about here.
Although the 700R4 transmission is no longer produced new, it is still considered to be one of the best overdrive transmissions ever produced. It boasts improved fuel economy and gear ratio in the first gear. The improved gear ratio gave drivers better acceleration when at a stop as well as making it good for off-roading. Additionally, it’s constructed of cast aluminum, weighing in at only 155 pounds.
One downside to this transmission is that because it’s used for vehicles that are driven hard, such as heavy-duty trucks and vehicles that haul heavy loads, it is prone to overheating in particular. We recommend adding a transmission cooler if you don’t already have one to prevent this problem as overheating can lead to a multitude of other issues. To learn more about common 700R4 transmission problems, read on below:
- Torque Converter Won’t Lock: a locking torque converter improves fuel economy by allowing for a true 1:1 connection between the engine and the rear wheels when traveling at high speeds. If it appears that the engine is turning faster than usual at highway speeds, you may have an issue with your torque converter.
- Valve Bore Wear: another failure to lock-up issue (or locking immediately after second gear) can be caused by too much pump bore to valve clearance. This problem allows oil to leak past the OEM spool and overwhelm the solenoid’s exhausting abilities.
- Not Shifting Right: The 700R4 is still a mechanically controlled transmission (with the exception of the locking converter circuit mentioned above), and depends physical pressure sensors and a sort of throttle position sensor to get it’s throttle position right. This throttle position sensor is called the “TV Cable” This cable acts like the kick down switch would on a TH350 in that it’s physical, but lets the transmission know exactly where the throttle position is like a 4L60E.
- Speedometer Not Working: The 700R4 uses both a traditional mechanical speedometer cable, like you might find in an older muscle car. Alternatively, they also used a variable speed sensor. This sensor is often abbreviated “VSS”.
- Engine Revs, but Car Barely Moves: this could be either an issue with having too little transmission fluid, or another issue that will need to be diagnosed by a qualified transmission specialist. If your transmission is leaking fluid or otherwise not functioning properly, it’s important that you bring it to Eagle Transmission as soon as possible to prevent dangerous driving conditions and further damage.
- Vibrating: if you notice a harsh vibrating as you drive, it could be a loose torque converter bolt or a driveshaft in need of balancing. Have your car diagnosed for free with Eagle Transmission
- Trouble Shifting: this is a problem that will need to be addressed by a qualified transmission technician. It’s usually a sign of a bad governor gear or a problem with your TV cable, but you should have your vehicle checked out to be sure.
- Overheating: transmission overheating is a very serious transmission problem that can lead to more serious issues down the road. This type of transmission is sometimes installed on vehicles that are not suited to its class such as heavy trucks or vehicles that are used for a lot of towing, causing the transmission to overheat. Make sure your transmission is rated for your specific vehicle’s weight, class, and the job you’ll be needing it for.
- TV Cable Problems: no, we’re not talking about the television in your living room. Your TV (throttle valve) cable controls line pressure, part throttle downshifts, shift points, detent (full throttle) downshifts, and shift feel. If the connection somehow becomes interrupted, you’ll have problems shifting properly and more issues.
If you notice any of these trouble signs and suspect that your transmission is having problems, bring your vehicle to Eagle Transmission right away to prevent further, and possibly costly, damage. Remember, it is never a good idea to drive your vehicle if you’re having transmission problems. Eagle Transmission offers free towing with major repairs. Give us a call today!