I changed the oil in my rear differential today and thought I'd post up a guide in here seeing as it is generally the same on most trucks
This is for the Ranger so you may have to look around your rear diff for some of the things I'm pointing out.
Stuff you'll need:
- 15/16" socket to remove the drain & fill plugs. VERY IMPORTANT: get a socket that grips on the sides and
not the corners of the nut.... the fill plug on the Ranger is rounded so the socket I had skipped off when I turned it....ended up using a 10" crescent to remove the fill plug. This is what I had in my kit:
Do not get this
this type is better... it grips the sides and not the corners
- replacement gear oil. I used Amsoil SAE 90 Gear Oil for LSD's. (Check your Owner's manual for the correct spec if you have a different make truck)
- Refill funnel, preferably one that has a flexible tube attached. The location of the fill hole is usually on the backside of the diff, so pouring in the oil right from the bottle is out of the question. See below for some suggestions:
- Bucket/container and rags to collect the old oil and for general clean up. PLEASE do not pour your oil down the drain, find your nearest collection centre and dispose of it properly. (It goes without saying, but I had to say it anyway.)
These are the steps:
1. Ensure that your Truck is parked on a
level surface and locate the drain plug and fill plug on the differential. Didn't take any pics before I started, but you'll see the general location in the pics below below.
2. Remove the Fill Plug FIRST. If you remove the drain plug first and have problems removing the fill plug, there will be no way to refill the differential.
3. Remove the Drain plug and collect the old oil in a container for proper disposal.
4. You'll notice that most drain plugs have a magnet attached to it to collect any metal filings that come off the gears during operation.
you can see the magnet here after I cleaned off the plug
this is the drain plug (with the white line on it) and fill plug, pictured side by side. Note the rounded corners on the fill plug. The copper washers were in perfect condition. I saw no need to change them, so they were reused.
5. After the oil has fully drain out, reinstall the drain plug and tighten it to specs (between 29-39 ft/lbs on the Ranger.... or you can use the "that feeling kinda tight method" which is in common practice in most garages today LOL!)
6. Attach your oil refill funnel to the fill hole....I'm kinda cheap so I fabricated something. Had a piece of flex tube in my junk box and found a plastic bottle to fit.
7. Using the funnel, refill the gear oil until it is at the brim of the fill plug hole. In my case, I knew from the owner's manual that the diff would take just under 2 quarts so I slowly poured when I got to the end of the 2nd bottle. As soon as the oil starts to seep out you can stop pouring.
8. Once the oil is at the brim of the fill plug hole, the diff has been filled to capacity. Wipe the excess oil clean, reinstall and tighten the fill plug and you're good to go!