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Oil Change

Everytime I go to my service center to get my oil changed for the 3000 miles, they always find something else. For example, on 1/30/09 they performed a rear differential drain and refill and then on 6/23/09 they did the same maintenance. What is a rear differential drain and refill and how often do I actually need one?

You had to AGREE to have that differential servce done, didn’t you? That being the case, you could/should have just said NO. I’ve known cars to go their ENTIRE 150,000 mile LIVES without ever having the differential grease changed. How often it SHOULD be changed differs with the car, and the type of differential it has. What does your owner’s manual say? I think you should go back, present both receipts, and ask for your scammed money back.

What sort of service center are you using? A chain type establishment like an Iffy Lube or Wally World? RUN, RUN like the wind. Find yourself a good independent shop, and use it.

I agree 100% w/MG. This is a RIPOFF shop, no doubt about it. There is no need for differential service any more that once every 5 years, if then (check your manual). Find another place to go.

Avoid quick lube places because due to their business plan will almost always relay on doing unneeded service and will employ under trained over worked staff who are paid to spend more time selling you service than they are allowed to do the service. Dealers while they are generally better are almost always more expensive.

The solution is to find a local independent mechanic.

Thanks for the comments. The car is a 2004 Chevy Trailblazer and my wife took it to Goodyear. We have been taking it there for the past three years since moving into the area. I thought it was just me but I will check out the manuel and take the car back. A $49 oil changed turned into a $500 service bill. I have recommended my wife take the car to a dealer but she likes this place for some reason. Thanks again for your comments.

I agree that this the shop appears to be ones of the rip-off types and I also agree that the car’s owner should familiarize himself/herself with what procedures are actually necessary.

However, I also have a suggestion to help the vehicle owner to keep track of what services have been done. Rather than having to dig through a stack of service invoices every time that you want to see when the differential was last serviced, or when the transmission fluid was last changed, or when the spark plugs were last replaced, it is much easier to maintain a small chart.

When I buy a new car, I take a piece of 8.5 x 14" paper, turn it sideways, and list all posssible maintenance procedures down the left side of the paper. Then, moving across the page, I draw vertical lines to make columns for each service interval. In effect, the result is a list on the left side of the page, with a row of vertical columns ranging across the page.

Every time the car is serviced (ranging from simple oil changes to the most complex maintenance procedure), I place an “X” in the appropriate column next to that procedure, along with the odometer mileage and the date. This way, I have a graphic that shows me–at a glance–what has been done, and when it was done.

I started doing this years ago after I mistakenly had the coolant changed twice within a year. Rather than making a mistake like that again, I decided that I needed a way to track what was done in order to readily see what needed to be done.

While I can construct my chart in the space of just a few minutes with a pen and a ruler, I am sure that it would also be possible to find templates for this type of thing online or possibly even within your existing software. No matter how you do it, just constructing a little chart and then updating it every time that the car is serviced will accomplish two things. It will prevent you from needless duplication of services, and it will help you to see when a particular service is due.

Piper, How Is This Trail Blazer Driven? Your Owner’s Manual Can Help You Determine An Oil Change Interval.

Many knowledgeable car enthusiasts who read and write these posts don’t change their engine oil as frequently as every 3,000 miles. You are possibly throwing your money away. While you are looking up the differential lubricant change interval in your Owners Manual/Maintenance Schedule, find a description of “normal” and “severe” driving conditions. You can possibly extend oil change distances.

Many people who fall into the “normal driving” category believe that 5,000 miles is more than adequate, although some manuals even recommend 7,500 miles or more. The oil change shops like you coming back as soon as possible.

Notice there is also a “time between change” recommendation as well. If those 1/30/09 and 6/23/09 oil changes (5 months apart) represent two consecutive changes, then the vehicle isn’t driven much and should probably follow a time interval, usually 6 months.


If this vehicle has Positraction GM calls for changing the fluid every 10,000 miles or so. That’s still a far cry from 3000 miles; yes that was a rip-off!!

Unfortunately these tire chain places (my experience has been Firestone) oversell services hoping you bite maybe one. They likely did not look at your past records and you may have a case for getting money back. I would ask.

I took my care to a Subaru dealer for a $300 full service at 30k miles bringing fully to date. A few weeks latter needed four new tires fine for $500, however the “mechanic” recommend $500 in additional work much redundant and other stating fluids in poor condition that were just changed. I simply smiled and said no and will never ever visit a national chain again.

These services are performed to prevent you from accumulating deposits in your bank account.

Find a reputable independently owned and operated shop to give your business to.