[Goohead]

Got some severe gear amsoil and their friction modifier I'll throw in where I get a chance

[Emoto]

Originally Posted by Emoto

Well, while my '16 2SS was in the shop for the trans line recall, I asked them to look into the rear diff noise. (After sitting overnight, mine will moan through the first few 90 degree corners of the day, until the fluid warms up. No grinding or metallic sounds)

Anyway, the tech called Chevy Technical and is doing some kind of fluid change. He had to leave before I spoke with the Svc Mgr, so we don't know exactly yet what they told him to do in terms of which fluid to use and whether to add friction modifier or anything, but I hope to find out tomorrow, assuming it is ready.

Fingers crossed.

Just picked up the car. They took pretty good car of me. I spoke with the tech and Chevy had him replace the diff fluid using the one with the friction modifier already in it, then drive it in figure 8s a few times to get the new fluid well distributed. He asked me to let him know if it comes back or anything, the Service Manager also told me to let him know how it goes and they'll dig deeper if it comes to that. No evident metal or anything in the fluid they drained; good that they inspected that.

So, I am pretty happy with this dealer. Nice people there. I gave the tech a cold case of beer as a thank-you. I know he was only doing his job, but when a service person does me right, like to recognize it with a small token.

[AndyUK]

Originally Posted by Emoto

. No evident metal or anything in the fluid they drained; good that they inspected that.

.

That sounds like a lie. Loads of pics on here of the state of rear end fluid when changed. I had a local shop swap my fluid at about 900 miles even though i didnt have the groan and it was practically silver through and through.

[Emoto]

Originally Posted by AndyUK

That sounds like a lie. Loads of pics on here of the state of rear end fluid when changed. I had a local shop swap my fluid at about 900 miles even though i didnt have the groan and it was practically silver through and through.

Well... obviously I cannot read minds so can't be sure. There is metal and there is metal, if you know what I mean. A certain level is to be expected as the gears get to know each other and is unremarkable. IME, typically there is some metallic looking sheen to some of the fluid as it drains due to very fine particles. I would not call that metal in what was drained, though. Perhaps I am being overly generous here, but I think he meant that there were no unusual concentrations of metal.

[CruzySS]

The metal is on the magnetic drain plugs. Changed mine at 1000 miles and was amazed on how dirty the oil was and the amount of Metal on the magnets.

[Goohead]

Anyone know the size of the crush washer on the fill and drain plug?

[AndyUK]

Originally Posted by Emoto

Well... obviously I cannot read minds so can't be sure. There is metal and there is metal, if you know what I mean. A certain level is to be expected as the gears get to know each other and is unremarkable. IME, typically there is some metallic looking sheen to some of the fluid as it drains due to very fine particles. I would not call that metal in what was drained, though. Perhaps I am being overly generous here, but I think he meant that there were no unusual concentrations of metal.

My shop guy looked at me funny when i asked him to drop the diff fluid at 900 miles. Couldnt believe what he saw and kept it for me to look at, it looked like a pot of mettalic paint.

[DanZ]

Wonder if it would be okay to blend oil brands?

I have some Mobil gear oil left over from changing the gear oil on another car. If I used a quart of the dexron, then topped it off with the Mobil, I wonder if that would affect the oils performance.

Thoughts...

Thanks

[JCunningham]

Different oils have different additives and some times they don't work together. I wouldn't on a car like this.

[CAM-FIFTY]

Just for the record, service manual lists 33ft-lb for both drain and fill bolts.