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   If does not matter if your towing, off-roading, city driving, commuting, or going for a Sunday drive, the fluid in your vehicle need to be performing.  No matter your style of driving, these fluids get hot and wore down, and one of the most over looked fluid changes is your rear differential. 

Some manufacturers recommend it be changed at 10,000 miles, but most now come with synthetic, and are approved to go over 100,000 miles.  The Diesel Garage's Ford F-250 was just over 10,000 ,miles when we did the change, and it was needed!

When we went out looking to upgrade our front and rear differential covers, we looked directly to PML.  There covers are stronger than the others out there, and they also have some of the best looking designs.  The covers were shipped to us with the hardware needed to do the install, all we needed was the oil and permatex.

We started the project by making sure the covers would fit the truck, and that the new hardware supplied was correct.  The new bolts supplied with the kit are longer due the thickness of the aluminum lip.  It is important to use the new bolts!

We then removed all the bolts except the very top one fro the rear differential cover.  The top one was left in to hold the pan up when we popped the seal and leaked the oil out.  The best way to start to separate the cover from the axle is with a small thin putty knife.  Insert it into the bottom corner making sure not to scratch the surface of the axle.  You can see a screw driver holding the cover out in the picture, that was used to put more space between the axle and the cover to allow the dirty oil to leak out slowly.  If you pop the cover off too fast, all the differential oil will pour out all over the place.

Once the oil was mostly out of the differential, the top bolt was removed, and we emptied the remaining oil into the catch pan.  The covers are sealed with a silicon, and that needs to be cleaned off completely to allow the new cover to seal with the permatex.  We found a brass brush and a brass putty knife to be the best tools to use to get this clean.  Once clean, we cleaned the machined surface of the axle with brake cleaner.  Be careful not to get this on the inside of the gears.  We also cleaned the machined surface of the new PML cover to ensure the surface is not oily.  While we were cleaning, we removed the factory magnetic fill plug.  WOW, it was covered in metal.  There was no doubt, this was a project that had to be done!

Following the instructions on the permatex, we put a 1/8th inch bead around the cover.  The cover was then put in place and snugged up on a criss-cross pattern. The flange bolts were tightened to about 20 pounds.  Teh PML covers offer a drain plug so there will be no need to remove the cover to change fluid next time.  PML also puts in a new fill plug to aid in filling the differential.  Both will make maintaining the axle easier.

The rear differential took just over 4.5 quarts and the front axle took 4 quarts.  PML covers add almost a quart of fluid to your gears to aid in oil life, and coolness of the fluid.

We followed the same process and completed the front cover in just under 30 minutes.  the total project takes about 2 hours, including clean up time.

Overall, the fluid needed to be changed in the rear differential.  It was full of metallic particles and the oil looked very dirty.  The front oil looked clean, but as you can see in the pictures, it was also riddled with shavings.  Our truck has had the 4x4 used on several occasions, but if your truck has not had 4x4 used much, I would suggest going for a ride down a dirt road in 4x4 to work in the front axle.

The oil that we used for this project cost about $100 and we put synthetic in the front, when the factory does not.  Just some added security for cold weather operation.

We also kept checking the axles for leaks once the vehicle was driven for periods of time.  We never had one, but its better to make sure, than to run your axle low on fluid.

If you are looking for more information on PML covers, or would like to see what models they make, visit there web site at or call them at 310-671-4345.



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