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I brought mine in at 5000 miles to have it changed the tech came out ten minutes later told me it looked like it just left the factory and it would be a complete waste of money to change it. So I didn’t. Brought it back with 20,000 miles this time the service manager told me he and his tech looked at a sample they sucked out and that it did not need to be changed.
After the summer driving season I plan to have it changed whether it needs it or not.
Changed mine after the first track event and then every 24 hours of track use after that, just as OM directs. If hadn't been tracking my car I would have followed the OM's normal service guidelines. No need to to it any more often. There can be all sorts of nasty looking pictures but that doesn't mean they represent when the fluid should be changed. Have driven a lot of cars in the 62 years I have been driving and only had two diffs go bad. I never change the diff fluid more often than the OM has instructed.
For someone who started working in a dealership in 1961 as soon as I got a license, I've found things have changed... a lot! We changed gear fluids quickly in those days and for good reason. The crap that came out with the oil(s) from differentials and transmissions was truly unbelievable by today's standards. (I'll refrain from commenting about non-detergent motor oils) Even the fluid in my 1990 New Departure 5-speed was still so filled with metal it was disgusting. But, metallurgy, machining, and lubes have gotten so much better there is no reason to second-guess the manufacturer's recommendations today, that is unless you just want something to do instead of driving.
At 21k With the amount of Crap on the magnet so glad I did it.3quarts with pump from Amazon about 70 bucks.
3qrts out 3 In
3 is a good number At Atlanta 2000.I took the photo before Happy Hour Woops Back on topic:
No plans to change mine until the recommended 45k miles. I've not seen anything that says definitively that it needs it earlier, it doesn't matter what it looks like when folks change it early, we don't know that it isn't meant to function just fine with some cloudiness. All those youtube vids mentioned above are folks assuming that it is bad but they don't know what GM's thoughts on it are or what the car was designed to deal with. Since GM says not to mess with it until 45k miles, I'd guess that means they are good with a little sheen in the fluid. If it bothers you change it though, it's your car.
I have seen some YouTube videos where guys changed their diff fluids relatively soon. (less than 5,000 miles) I'm curious how soon some of you changed yours.
5000 miles. But I track mine. Very easy to do yourself. I bought one of these:
For someone who started working in a dealership in 1961 as soon as I got a license, I've found things have changed... a lot! We changed gear fluids quickly in those days and for good reason. The crap that came out with the oil(s) from differentials and transmissions was truly unbelievable by today's standards. (I'll refrain from commenting about non-detergent motor oils) Even the fluid in my 1990 New Departure 5-speed was still so filled with metal it was disgusting. But, metallurgy, machining, and lubes have gotten so much better there is no reason to second-guess the manufacturer's recommendations today, that is unless you just want something to do instead of driving.
Yep, metallurgy and manufacturing have gotten so much better now. That's why C7 wheels never seem to crack or bend.
Had mine changed out when I took it in for the 500 mile oil change. Did it need it? Probably not. But now I don't have to wonder if it was under filled. Or do I?
Had mine changed out when I took it in for the 500 mile oil change. Did it need it? Probably not. But now I don't have to wonder if it was under filled. Or do I?
I did the same at around 600. There was grit and fine metal shavings on the drain plug. Oil color was mostly clean but has a layer of silver slime on the drainage bolt. I would recommend it to anyone before 1000 miles.You don't want that grit circulating in your gear box.
rear diff fluid...you guys using the OEM stuff as a refill? Or something else? I'm doing mine soon. I believe it'll be the first time...maybe 2nd. But the 1st time I'M doing it.
60K on the car. No track days yet...this year tho...I will track it.
I had the dealer do it at the 500 mile oil change. At the time, I'd seen a few threads on here about 1) underfilled diffs, and 2) diffs that had fluid that come out looking terrible. I figured for $110 (or whatever it was) it was a cheap way to get some peace of mind.
