I just had my dealer put in 4.10's and had them add the FRRP axle girdle when they did the install. I picked up the car and the gears were great - I took it easy and drove about eight miles to the house and parked the car. The next day I went in the garage and noticed the dreaded shiny pool of liquid underneath the rear end. I took it to the dealer the next day and they thought it was the drain plug so they took it out and taped it - it was funny watching one tech hold his finger over the drain hole to hold the HOT gear oil in while another tech taped the plug. They got it back in and I took off. The next day, the same little pool was under the car. Not good. Took it back to the dealer and left it with them. Just picked it up and it turns out that the gear oil was leaking out through the two load bolts. Not much but enough. They took the axle girdle off and taped the load bolts and used liquid teflon as well. They also used silicone in place of the gasket. So, if you put on the girdle and get a leak, start with the load bolts as a start to solve the problem.

 

+1 for both statements.

My gear installer did both right off the bat.

 

The Ford tech didn't use the silicone because the directions for install said no silicone, gasket only. That's how we learn - screw it up first and then do it right the next time.

 

That's interesting because the factory doesn't use a gasket on the stock differential cover. Why FRPP includes a paper gasket is beyond me.

 

It turns out the paper gasket wasn't the problem but once you take the girdle off, the gasket is t/u.

 

Still had a small leak this am so I took it back to the dealer. They put it on a lift and it appears that the top fill plug was the source of the leak this time (and probably the last time). The plug was wrapped with teflon tape and so far it looks dry. I'll check it tonight after I drive home. So, if you add a girdle, tape the fill and drain plugs for sure. Check the load bolts too.

 

Hopefully this will be the last visit to the Dealer for you.

 

The plus side is that I'm racking up "they owe me points".

 

Be sure to cash in on those points before they forget!