Differential oil change questions
02-16-2022, 07:16 PM
#1
Instructor
Thread Starter
Differential oil change questions
I want to change the fluid in my differential but have a few questions.
Can i change the oil on a lift/jack stands. I know the manual for my truck says change only on level ground. Will it cause a problem if I raise the car and change the fluid?
If i purchase Mobil 1 or Royal Purple is the additive still needed? If they cover limited slip would I be over doing it.
Proper weight and how much oil? I have seen from 1.3 quarts to 3 quarts of oil. Just want to double check.
When the fluid runs out of the top hole we are good or is that to much fluid? My boat is so much easier three plugs and cant mess up the fluid level.
What does everyone use to seal the bolt when closing up the plug?
If i am missing the answers please forgive me been trying to find the right answers and feel like i am running in circles
Can i change the oil on a lift/jack stands. I know the manual for my truck says change only on level ground. Will it cause a problem if I raise the car and change the fluid?
If i purchase Mobil 1 or Royal Purple is the additive still needed? If they cover limited slip would I be over doing it.
Proper weight and how much oil? I have seen from 1.3 quarts to 3 quarts of oil. Just want to double check.
When the fluid runs out of the top hole we are good or is that to much fluid? My boat is so much easier three plugs and cant mess up the fluid level.
What does everyone use to seal the bolt when closing up the plug?
If i am missing the answers please forgive me been trying to find the right answers and feel like i am running in circles
02-16-2022, 10:47 PM
#2
Melting Slicks
There is no drain plug so unless you want to take it all apart it's what you can suck out. Usually a little over a quart. I've never changed a fill plug gasket and never had a leak. You do not need additive if the lube already has it. You want 75W-90.
02-16-2022, 11:25 PM
#4
If this is a 'higher mileage' car and you doubt it's ever been serviced do the GM/ACD Additive. There's no need for the Synthetics but there's also no valid reason NOT to.
02-17-2022, 09:37 AM
#5
Melting Slicks
When I sucked the fluid out of my 96 rear I realized that you can't really suck out all the fluid. I came up with an idea that worked great but was a little messy. I have an old shop vac. I taped a 3 foot section of 1/4"ID clear tube to the shop vac hose. This small hose was able to get into nooks and suck out a lot more fluid. Since it was clear I could tell when I was in a spot where fluid still was. The inside of the shop vac was a mess but the system worked great. Dan
02-17-2022, 06:28 PM
#6
Instructor
Thread Starter
great tip on the size of the bottles. That explains needing three bottles but not three quarts.
Last question A thread sealant does not go on the plug when closing it up. Does it have a rubber/copper gasket or anything to seal it?
Last question A thread sealant does not go on the plug when closing it up. Does it have a rubber/copper gasket or anything to seal it?
02-17-2022, 06:34 PM
#7
No gasket/seal and generally shouldn't require any sort of sealant! The car may or may not have a tag hanging from the plug.
02-19-2022, 10:11 AM
#8
Melting Slicks
Does it really matter if you don't "get it all out"? Probably not, as long as it isn't contaminated by water from being in a flood or some other extraordinary event.
I use a vacuum pump thing that I use on the boats. It has a 1/4" plastic tube that can be snaked down to the bottom of the cavity. I changed the fluid in my 90's Dana 44 this way, and it took 2-2/3 bottles to fill it back up. That is almost to the ounce what it takes to fill one that was disassembled. Note that GM bottles are not 32oz Quarts. They are 23oz. So 2-2/3 is 62oz, or just under 2 qts. I just went out to the shop and checked. The bottle I have left over from the change only has a few ounces in it. I always buy 3 bottles. I got it all out.
I use a vacuum pump thing that I use on the boats. It has a 1/4" plastic tube that can be snaked down to the bottom of the cavity. I changed the fluid in my 90's Dana 44 this way, and it took 2-2/3 bottles to fill it back up. That is almost to the ounce what it takes to fill one that was disassembled. Note that GM bottles are not 32oz Quarts. They are 23oz. So 2-2/3 is 62oz, or just under 2 qts. I just went out to the shop and checked. The bottle I have left over from the change only has a few ounces in it. I always buy 3 bottles. I got it all out.