Hi,

I, have a '57 ford Ranchero that has a pinion shaft seal leak. I just put in a neoprene seal thinking this would correct the problem over the stock leather type seal. I have replaced the differential yolk 5 or 6 yrs. ago with a N.O.S. part. To date there still is no wear on the part where the seal rides. I, did use permatex II non drying type on the pinion shaft splines before installing the yolk. I do use full synthetic 75-90 weight gear oil for both the overdrive transmission and the differential. I'm certain that I used one of these neoprene seals with conventional 90 weight gear lube yrs. ago and still had a bad leak. I think I'm going to go back to the std. leather seal, it's currently soaking in light oil to make the leather seal swell prior to installation. It'll most likely leak but should not be leaving puddles in the driveway or on the garage floor! I've had my car for almost 20 yrs. and there always seems to be something that'll make me scratch my head! Final note the vent located on the brake line jct. block is open. I know cause I heard air coming into the diff. while I was draining the oil with the fill/level plug still installed....

Thanks for the help,

Jeff