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Hi all-so i'm on the last leg of all the fluid changes to our first vette. Today was diff fluid. Ive changed diff fluids in both my toyota trucks before. Never looked like this tho-they were just dark and cruddy from the PO's never doing it. From my experience with my trucks, this looks like WAY too much silver...am i just too worried or should i start putting some extra money away every month for a new rear end
ps-i think this fluid had about 23K on it, as it looked like whoever changed it last wrote the mileage on the diff (21,000+ and i'm at only 44,500) No big chunks on the drain plug, just a small amount of sand sized particles on there.
Thanks tons for your opinions....i think!
jp
nope-no whining at all...it was weird as i put a magnet thru it and the magnet didn't move the shimmer at all, which has me wondering if its some funky additive that the PO put in there? But i can't imagine they would make it silver!
I don't know what GM puts into their differentials, when assembled, but I've regularly changed the oil in EVERY one of my differentials, going back to the 70s. And EVERY one of them looked like that for the first 2 changes. (For that matter, so did the first oil fill that I drained from my '15 Jeep Grand Cherokee) Usually by the 3rd change, the oil looked pretty good, and that was usually the final change, at least during my ownership.
Since a C-5 has a drain plug, as well as a fill plug, an gear lube swap, or two, isn't all that hard or messy to do. If it were my car, I'd try that first, before pushing the panic button.
2020 Corvette of the Year Finalist (performance mods)
C5 of Year Winner (performance mods) 2019
put good fluid in it and keep an eye on it, worst case if it does need to be replaced you can find good used differentials for pretty cheap and they aren't hard to replace if you have the tools to do it
good info-thanks tons for all the feedback for sure. sounds like i'll hold off on freaking out at least for a bit! yes, replaced the fluid with amsoil severe gear + slip lock (purchased through brad / C66 Racing who is a supporting vendor and AWESOME to deal with btw). I will put a quick turnaround fluid change on the calendar and see what it looks like then-hopefully it will be like leadfoot says .... here's hopin! (good point - no reason not to as its an easy cheesy thing to do besides the STINK of diff fluid-got some on my watch band and i'm soaking the darn thing in dawn soap over night )
I remember changing fluid on my old F-150 truck many years ago, and the fluid looked like silver paint right out of the bottle. Can't remember what I used but think it was some kind of fluid recommended to help with clutch chatter which was common with the Ford trucks back then.
It COULD be gear marking compound from a ring & pinion install. I found that same color on a new police cruiser that I was servicing & that's what it was. Change it & keep an eye on it.
I changed the Front Differential fluid in our X5 BMW at 95K, it looked like that, scared me a lot. Re filled with new fluid and sent off a sample to a test site I found on the AMSOIL website.
Took about 3 weeks to get an answer. They told me the oil was perfect, no sign of any foreign material in the fluid to indicate any bearing or other wear in the differential.
I was nervous till I got the oil report back. It was not that expensive, around $60 if I remember correctly and worth every penny. I was looking to swap it out for a new one.
Hope this helps.
Last edited by Westlotorn; Jun 7, 2019 at 10:27 PM.
From: Central PA. - - My AR15 identifies as a muzzleloader
I believe in the Beer Fairy
I don't think you have anything to worry about, if you didn't hear anything, the way the oil looks is not a good indicator. I just changed mine and it was maybe not as ugly as yours but it definitely had a metallic Shimmer to it. My oil analysis came back just fine. I did the same for my transmission and it absolutely convinced me and another person that the transmission was going to need work, and it came back with absolutely no metal in the oil or contamination. Wasted it was quite a bit better than normal for that mileage.
Go to this place and order a sample kit and then send it in after you've got 500 miles on the oil. Their samples are $28 each and that includes the shipping. The bottles come as a prepaid mailer.
ours on the other hand ours came out just like the OP's and the bellville washers wore broken and started chewing the posi plates and carrier ???
with the car in air can you turn the rear wheels independently ???? should not be able to do so !!!!!
Wow guys....ummmm, I posted this like almost 2 years ago!!! Haven't had any problems with the rear diff at all-in fact when the slave puked on me and we changed the clutch, slave, blah blah blah, actually changed the rear end seals, cleaned and lubed the splines, and other stuff that I can't remember (since the whole rear end was dropped), but the rear diff fluid was A OK. so, guess we can close this one!
Wow guys....ummmm, I posted this like almost 2 years ago!!! Haven't had any problems with the rear diff at all-in fact when the slave puked on me and we changed the clutch, slave, blah blah blah, actually changed the rear end seals, cleaned and lubed the splines, and other stuff that I can't remember (since the whole rear end was dropped), but the rear diff fluid was A OK. so, guess we can close this one!
I was reading another post in the C2 section and when I got to the bottom of that post somehow I found myself reading this post. When I say your pics of the oil you drained it brought back my panic seeing the oil out of our X5 BMW.
Like the original poster I was in a panic till I had that old oil tested and it tested perfectly good with no concerns. Worth every penny spent on the test for peace of mind. Sorry to bring up an old thread.
no worries guys-it was kind of funny. i remember we decided to get into vets because restoring vintage mustangs always involved fixing something after a trip to a show or a cruise. We wanted something that was still fun but reliable...and i think the rear diff was the first fluid change i did. Talk about an oh crap moment!
It's awesome to see the loop on this closed from an old thread. Really reinforces that sometimes it just looks like that and it's okay; and that maybe sometimes there's no need to spend $$$$ to repair what may not even be an issue at all.
Too much "silver" in this diff fluid??
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