A little help please
Thread Starter
4th Gear
Joined: Nov 2009
Posts: 4
Likes: 0
A little help please
so im sure this has been talked about many times but here goes anyway, i want to change the fluid in my rear diff. ive looked through both an aftermarket shop manual and an original factory shop manual, both just say drain fluid and replace. what alot of help that is. my father says when he drained it there was a drain plug. ive looked like crazy and cant find anything. so i guess my question is what is the best way to change this, and how much fun is it to take it apart?
Thankyou
Thankyou
Safety Car
Joined: Aug 2000
Posts: 3,711
Likes: 43
From: San Antonio TX
There are only two ways to drain the diff fluid: 1) suck it out of the fill hole. Obviously, this won't get all of it, but most of it, or; 2) drop the driveshaft, remove the pinion yoke and knock out the pinion seal.
There is no drain plug on the diff. You could put one in by drilling and tapping the housing. Why is there no drain plug, you might ask? Because there is no service interval on the differential. It has, more or less, an infinite service life on the gear oil and the additive. Questionable, maybe, but unless there is some prevailing reason to do so, there's no reason to drain the differential gear oil.
There is no drain plug on the diff. You could put one in by drilling and tapping the housing. Why is there no drain plug, you might ask? Because there is no service interval on the differential. It has, more or less, an infinite service life on the gear oil and the additive. Questionable, maybe, but unless there is some prevailing reason to do so, there's no reason to drain the differential gear oil.
Instructor
Joined: Apr 2004
Posts: 161
Likes: 0
From: Grand Island NY
I wouldn’t take it apart, go to the auto parts store and ask the guy behind the counter for a turkey baster like device, explain what you want to do, I can’t think of the name of it.
Don’t forget the posi additive if you have a posi.
Don’t forget the posi additive if you have a posi.
Melting Slicks
Joined: Sep 2004
Posts: 3,226
Likes: 667
From: Northeast
At the top of each forum there is "search this forum". Just click and put in a few words and it will find some postings for you to read.
This came up:
http://forums.corvetteforum.com/c3-t...diff-lube.html
I recommend buying an 8pt 5/8 inch socket (and a swivel) to remove the square plug unless you find you have room. I didn't on my 78. Good luck.
This came up:
http://forums.corvetteforum.com/c3-t...diff-lube.html
I recommend buying an 8pt 5/8 inch socket (and a swivel) to remove the square plug unless you find you have room. I didn't on my 78. Good luck.
Thread Starter
4th Gear
Joined: Nov 2009
Posts: 4
Likes: 0
thanks for all the help, everything went great. i just used my engine oil sucker tank. put the tube in pumped it up and waited till the 90wt came out. the filled it back up. thanks again for all the help
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
Go to Target and buy a cheap turkey baster. Hook a length of plastic tubing to it (3/8" would be good...thick diffy lube is kinda tough to suck up). Get the fill plug loose before you do anything else; it is hard to find the correct socket to fit the plug. If it is really on there tight, you may have to remove the spare tire & carrier to get an extension bar on your breaker bar. Anyway, once you get the plug freed-up, take the car for a drive to warm up the gear lube. Then jack up the rear and pull the plug. The baster will take a bit to expand the bulb and get the lube into the tube. Just take your time and get as much of the old stuff as you can out of the 'pumpkin'. If you need, you can add some thinner oil in the rear end before you warm it up; that will thin it, as well.
Put some good quality gear lube and a tube of GM Posi-trac additive into the diffy and lock it down for another 5 years.
Put some good quality gear lube and a tube of GM Posi-trac additive into the diffy and lock it down for another 5 years.
