Changing Differential Oil...
Thread Starter
Le Mans Master
Joined: Mar 2006
Posts: 5,262
Likes: 0
From: E. Amherst NY
Changing Differential Oil...
'86 L98, D36. I want to change the gear oil in the rear end before the drag strip opens back up.
Instead of dropping the differential to drain it, I was hoping to use my vacuum oil changer I use for the boat. Planned on going in through the oil level screw and sucking it dry. Anybody done this before?
Instead of dropping the differential to drain it, I was hoping to use my vacuum oil changer I use for the boat. Planned on going in through the oil level screw and sucking it dry. Anybody done this before?
Le Mans Master
Joined: Oct 2007
Posts: 9,682
Likes: 3,433
From: Akron Ohio
2025 Corvette of the Year Finalist - Modified
2024 C5 of the Year Winner - Modified
2023 C5 of the Year Finalist - Modified
2022 C5 of the Year Finalist - Modified
St. Jude Donor '09-'10-'11
I know people have recommended sucking it out, I personally just drilled a hole in the bottom and tapped it then plugged it. The vacuum method should work though. Just make sure you get the hose as low as it can go to get as much of the old oil out as you can.
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
Sucking the old fluid out is the best way. Unless you are sure where to drill, it can be a big "Oh S***!" if you drill in the wrong place 
.
The accessory catalogs used to carry a kit to install a drain plug and came with a template to show exactly where to drill. Don't know if they are still offered, but you can get 95% of the old fluid out even by using one of the Harbor Freight $5 hand pumps. And you use the same pump to put the new fluid in along with the GM additive.
.The accessory catalogs used to carry a kit to install a drain plug and came with a template to show exactly where to drill. Don't know if they are still offered, but you can get 95% of the old fluid out even by using one of the Harbor Freight $5 hand pumps. And you use the same pump to put the new fluid in along with the GM additive.
Thread Starter
Le Mans Master
Joined: Mar 2006
Posts: 5,262
Likes: 0
From: E. Amherst NY
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
Team Owner
Joined: Oct 2000
Posts: 96,443
Likes: 9
From: Fort Knox, KY
Cruise-In IV Veteran
Cruise-In VI Veteran
Cruise-In VII Veteran
Cruise-In VIII Veteran
I used a fluid pump I got from Harbor Freight Tools. It attaches to a 1/4 inch drill. Similar to the ones they carry in the J.C. Whitney Catalogs. Works well and it's reversible, too. 
http://www.jcwhitney.com/Auto-Parts/...FQETGgodXWjN5g
http://www.jcwhitney.com/Auto-Parts/...FQETGgodXWjN5g