Have any on you pumped the rear diff oil out as opposed to removing the pumpkin cover.

Out of curiosity, I went to a Chevrolet dealership to inquire. The service tech said that that's how they do it and he wanted to charge me $270!

 

I wouldn't,you won't get it all and the nasty sludge that contains particles will still be in the bottom of the pumpkin.

 

I have a vacuum pump with a reservoir and assortment of hoses I could suck it out but like Y2Keglide said I would still pull the cover if you have never done it before. If I was replacing fluid every 2 years as routine maintenance I may pull the cover every other time. If its been a long time since its been done you really want to wipe out the inside bottom of the pumpkin. Since gear oil does not get that hot its biggest issue on a posi rear oil is clutch powder contamination. The residue all sinks to the bottom once the car stops moving. Now if your car is not posi give it a good cleaning and switch over to synthetic and then just check the level every year and watch for leaks. No real need to change it.

Any setup you would buy to suck out oil will cost way more then a pumpkin gasket. The rear oil is thick and not easily sucked out by a light hand pump.

For a car this old you should find a good mechanic that is not a dealer. There is a reason a lot of people call them Stealership. $270 for a half hour of work is insane. Don't get me wrong if you have a late model car that has a technical issue the dealership has the right equipment and training to get the job done. Back when I was a tech we used to fix newer cars that had issues that independent mechanics had given up on. They simple did not have the equipment to do the job while the dealer had to have it because GM said so. But I knew some things like maintenance, brakes, front end alignments and exhaust work their where better people out there to do the work. I had to work on every aspect of a car how could I be as good at front end alignments as a guy that did them 8 hours a day every day.

 

You guys are absolutely right. I'm gonna change the diff oil myself. After contacting the dealership and two independent shops, I lost all confidence and trust
that they would do the job right or at least to my standards. The one shop that claims to be a GM LS specialty shop wanted $400 bucks!

By the way, How many quarts of oil does the diff take? I couldn't find it in my owners manual.

Thanks again

 

HOLY RIP OFF. I am a mechanic turned engineer sounds like I now have the lower paying job. If your a newer guy without power tools and a quick way to jack the car up it may take you an hour, Search out a you tube video about inspecting a GM rear differential. But to a guy with a lift and power tools I would expect to spend as much time in the parts room getting my oil and gasket as the job would take.

These prices are getting crazy. My weekend lowes/parts running truck needed a ball joint for PA inspection. This thing is a POS Dodge with 250k on the clock and this was a mechanic I have been going to for years. He wanted $800+ to replace one lower ball joint. I bought the Ball joint for $29 (not the cheapest on Rock Auto) I got the Dodge ball joint install/uninstall tools from Amazon for $69 and I did it in my drive way in about an hour using a jack cause my lift is tied up with a project. Its getting to the point on old cars if you need 2 ball joints and two tie rod ends and you pay to have it done the car is totaled.


2 quarts and if you have a posi rear you need the additive. It will not hold 2 more like 1.75

 

You'll have more time in cleaning up the gasket surface than anything. 2 quarts should do it.

The prices you posted is the exact reason I am glad I do everything (with the exception of inspections) to my own vehicles. I know it's done right and I only spend the money that's required on the parts. I can only imagine what the bill would have been had I let a shop do the head gaskets in my DMax.