1993 and newer General Motors vehicles equipped with the 4L60E, 4L65E and 4L70E automatic transmissions have always been plagued with 3-4 clutch failure. There are many different reasons for it, but probably the most often overlooked reason is a leak at the reverse abuse plug in the valve body. This plug acts as a separator and a seal between the 3-2 downshift valve and the reverse abuse valve.
In third gear, the 3-4 clutch oil goes between the 3-2 downshift valve and the plug to stroke the valve towards the spring. There is constant spring force pushing the plug on one side and 3-4 clutch oil going to the opposite side. Because of that, each time the 3-4 clutch oil comes and goes, the plug slightly moves in its bore. Loosely held in place by a roll pin, the soft factory aluminum bore plug wears out over time. The more it wears, the more 3-4 clutch oil can leak past the plug into the other side which is open to the sump. In addition, to make things worse, the leak is downstream of an orifice feeding the 3-4 clutch. As a result, it can cause a 2-3 shift flare or a 2-3 shift overlap. Consequently, it is sure to be a slow silent killer for the 3-4 clutch.
Our TransGo drop-in steel plug is longer with a slightly larger O.D. than the OE plug which virtually eliminates the plug leak. We have designed and manufactured the plug with a harder material and greater interference fit to keep in place. This is a solid solution to the plug leakage. The plug also features a threaded hole on one end for ease of installation. A long bolt is also furnished for installation and enough parts to fix five units.
- Burnt 3-4 clutch
- Flare 2-3 upshift
- Burnt 2-4 band
- (5) Precision USA-made steel plugs
- Threaded bolt