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slow but steady drip 727 transmission


Local time
2:29 PM
Dec 31, 2018
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Kelowna BC Canada
Question, I have replaced the output tail shaft seal on my 727 and a fresh rebuild tranny c/w shift kit with less than 200 miles on it. I am seeing a drip coming past the new seal down the shaft and sits on the u-joint until gravity pulls it to the floor. Car is on my hoist and I am wondering if I purchased a bad re pop rear shaft seal or is there something going on inside the transmission.
Thanks for your help,
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If it is running down the face of the seal, it is the seal itself or the seal is not sealing to the extension housing [ use some silicon when installing the seal ]. If the rear bush was worn & not replaced, that could cause a fluid leak also because the yoke is wallowing around.

Many trans yolks have a plug in the end to stop fluid leakage. If this a is the problem, would expect to see fluid around the u joint.
Do you have the original sliding yoke? Early models were vented with a hole in the spline plug. To use those early style yokes a seal that slides over the output shaft splines must be used. The yoke is then sealed and must be manually greased to allow the sliding action to occur without spline wear.