View Full Version : Why do we have rev limiters and speed limiters?

10-28-2002, 06:57 PM
All 4R70W SCís have rev limiters because the 12 inch torque converter starts
to balloon around 5400 rpm. If it balloons enough, the trust washer could eject.
Therefore, the rev limiter keeps drivetrain speeds down.

The speed limiters are present in the 4R70W SCís because the driveshaft starts
to bend near its critical speed which can depend on rear gear ratios and tire
sizes. The critical speed is when the driveshaft starts whipping in the middle
rather than spinning on its true centerline. This bending creates a vibration or
frequency. The frequency can cause the tailshaft housing to fail. The rear
bushing also gets much hotter and can spin thus dropping the driveshaft at high
speeds. The M5R2 equipped SCís and XR7ís donít have this problem because
the driveshaft is shorter and the tailshaft housing doesnít see as much
frequency. --- compliments of A-Train