Well, I just took a look at my rear diff, and I just noticed that there's fluid coming out of the tailshaft (pinion?). Is there a seal back there that I need to replace?

Man am I having some of the wierdest problems I've ever faced with this truck. How hard is it to pull that seal out and replace it? Am I just going to have to remove the driveshaft and pry the seal out? It doesn't look that easy, I hope it is though.

'87 F150,
Black w/Red Stripe paint,
6" Lift,
33"x15.50",
I6 300 4.9L,
3.55 true-loc rearend,
New (Used) Rebuildable HUBs!
Man Am I glad I did that upgrade!

 

Yes, there is a seal behind the yoke. Drop the driveshaft, pull off the yoke, and replace the seal. The only problem is that if it's a 9", you need to put the same amount of torque on the nut as it had before you took it off or the bearing preload may not be right. 9" ford axles had a crush sleeve that preloads the pinion bearings. You basically tighten the pinion nut until you feel the sleeve give, then you tighten the nut until the preload falls into spec. The preload is adjusted by turning the pinion by the nut with an inch-pound torque wrench until you reach about 8-12 inch pounds with old bearings and around 20 for new ones. These numbers may not be exact, but you get the idea. You can look up the specs on the net. You can take out the pinion support, replace the seal, put the yoke and nut back on, and then, with the support in a vise, set the preload to spec. Then just put the support back in and attach the driveshaft. The pinion support is the housing that the pinion is in. It has 5 bolts holding it, and should have some shims under it. Be sure to put the shims back and clean the yoke where the seal surface is. It's real easy to do. Have fun!

 

Oops! I see you have an '87. It's probably got an 8.8 rear. It's the same, but you can't remove the pinion without removing all the gears and axles. I would just see how much torque it took to remove the nut, replace the seal, then put it back at the same torque. Dave

 

You are 'da man! I will work on getting that seal replaced. It definitely doesn't sound really hard at all! Thanks for the info!

'87 F150,
Black w/Red Stripe paint,
6" Lift,
33"x15.50",
I6 300 4.9L,
3.55 true-loc rearend,
New (Used) Rebuildable HUBs!
Man Am I glad I did that upgrade!