Cannot seem to stop my rear axle from leaking around yoke. I've replaced seal twice but no good.On warm days when truck hasn't been moved, it will sometimes leak. Any suggestions, thought it could bethe ring and pinion gear.

 

Was there a 'groove' cut around the seal 'running surface' on the yoke?, also, they can leak from around/through the 'splines' and out the pinion nut.. If the pinion isn't loose, and the was correct seal/s, and installed correctly, thats about the only 2 ways you'll get a leak there...

 

Another couple culprits relate to balance and wear. If your driveshaft is out of balance or your rear end gears or rear transmission bushing have real heavy wear on. If you have vibration or shaking at certain speeds it could be a hidden problem like these. Also if (like Hayapower said) it has a groove you can sometimes get a sleeve to go in place over the area else you'll have to get a new yoke. Beware first though that a parts store (non-Ford parts) didn't sell you a wrong or scrappy seal.

 

Thanks for the info everyone, I'll probably try one more seal (verify correct partthrough Ford dealership) and then go from there.

 

Going on 3 weeks and no more leaks. Ford no longer made the seal but they referred me to NAPA who carried the identical one. Thanks again for help!