ZL1 Diff / metal debris?

JSH · 04-28-2025, 10:49 AM

This pic was taken this morning of my rear differential plugs. Yhe drain had a big ball of essentially liquid metal stuck to it and that's what's on my right thumb. Has anyone seen this before but clearly there's a bunch of metal on metal wear going on in there. Obviously the plug is designed as a magnet to collect such debris but I'm asking about the quantity. I don't recall ever changing the differential fluid until today. It has 16,500 mi on it

*radz28* · 04-28-2025, 10:57 AM

I've had some amount of that kind of debris. I changed within 1000, and 3000 miles or something. It was better at the 3000 mile mark.

Mark R · 04-28-2025, 11:49 AM

You are pretty late on the diff fluid change. I would change it again in a couple thousands and see what you get. It's likely just all the normal stuff from the first 16,000 miles.

2SS Capt · 04-28-2025, 12:25 PM

Quote:

Originally Posted by JSH

This pic was taken this morning of my rear differential plugs. Yhe drain had a big ball of essentially liquid metal stuck to it and that's what's on my right thumb. Has anyone seen this before but clearly there's a bunch of metal on metal wear going on in there. Obviously the plug is designed as a magnet to collect such debris but I'm asking about the quantity. I don't recall ever changing the differential fluid until today. It has 16,500 mi on it

Since you haven't changed it until now, I'd say that is probably pretty normal, I changed my diff and 505 and again at 1,500, the first had a lot, the second had some, by the time I changed it again at 5,975 there was hardly anything on there... At the 9,468 change there was virtually nothing on the plug...

I agree with others, not that you can do anything about it now, but 16,500 to the first change seems very long to me...

*Joshinator99* · 04-28-2025, 01:44 PM

Quote:

Originally Posted by Mark R

You are pretty late on the diff fluid change. I would change it again in a couple thousands and see what you get. It's likely just all the normal stuff from the first 16,000 miles.

Quote:

Originally Posted by 2SS Capt

Since you haven't changed it until now, I'd say that is probably pretty normal, I changed my diff and 505 and again at 1,500, the first had a lot, the second had some, by the time I changed it again at 5,975 there was hardly anything on there... At the 9,468 change there was virtually nothing on the plug...

I agree with others, not that you can do anything about it now, but 16,500 to the first change seems very long to me...

Agreed. Did my first diff oil change at 1000 miles and it had some break-in crud on it. Subsequent diff oil changes were clean.

clg82 · 04-29-2025, 06:41 AM

Totaled.

SOCAL.M6.ZLE · 04-29-2025, 08:03 AM

Like others have said... based on GM's recommendation you are very late for your first change, and my results were similar for my first change at 500 miles once the gears are broken in, and then at by 1,500 miles things looked alot better. Changed once again at 5k miles and the drain plug was alot cleaner. That said, I am confident your next one will look alot better

JSH · 04-29-2025, 08:15 AM

The manual says 30,000 to 45,000 mi so I'm actually early haha.

Anyone know the torque specs for the plugs. Seems like 25#?

I'm going to put two new quarts of fluid in there today

WhiteMale · 04-30-2025, 06:50 AM

Looks like every other first and or second diff oil change that I've done and seen others post.

Gunkk · 04-30-2025, 07:29 AM

Quote:

Originally Posted by JSH

Anyone know the torque specs for the plugs. Seems like 25#?

Close enough. Fill and drain plugs are the same, ELSD = 24 ft-lbs

wakespeak · 05-01-2025, 10:24 PM

Normal for that many miles I would say. I change mine after every track event. Just snug the bolts until they stop with a socket wrench. No need to put any muscle into it.

Patriot Motorsports USA · 05-02-2025, 07:26 AM

For the miles, that is early. Good thing your eLSD has the magnetic plug!! I would recommend changing it far more frequently as it goes from "Open to Fully Locked" in .03-seconds, so you can imagine the force it takes to do that and the gears, clutch plates and such can take a beating! Just change it with every oil change for a while and you will see it stay clear soon.

I bought the 5-gal pail from Amsoil with their hand pump and it makes changing the rear diff fluid a five minute ordeal.

04-28-2025, 10:49 AM	#1
JSH Drives: '20 ZLE Join Date: Jun 2020 Location: Mile High Posts: 4,195	ZL1 Diff / metal debris? This pic was taken this morning of my rear differential plugs. Yhe drain had a big ball of essentially liquid metal stuck to it and that's what's on my right thumb. Has anyone seen this before but clearly there's a bunch of metal on metal wear going on in there. Obviously the plug is designed as a magnet to collect such debris but I'm asking about the quantity. I don't recall ever changing the differential fluid until today. It has 16,500 mi on it Attached Images __________________ 2020 ZL1LE A10. LME LT4 390 short block, LME CID Heads, Kong E2650, FBO. 15" conversion, MT ET Street R 325/15. 100 octane: 1045hp/1055tq. 100 octane + Meth (1x10+): 1117 hp/1067 tq

04-28-2025, 10:57 AM	#2
radz28 Petro-sexual Drives: Ultra-Grin Join Date: Oct 2006 Location: Crazy Coast Posts: 15,855 View My Garage	I've had some amount of that kind of debris. I changed within 1000, and 3000 miles or something. It was better at the 3000 mile mark. __________________ '20 ZL1 Black "Fury" A10, PDR, Exposed CF Extractor Magnuson Magnum DI TVS2650R // RFBG // Soler 103 // TooHighPSI Port Injection // THPSI Billet Lid // FF // Katech Drop-In // PLM Heat Exchanger // ZLE Cradle bushings // BMR Chassis-Suspension Stuff // aFe Bars // Diode Dynamics LEDs // ACS Composites Guards // CF Dash // Aeroforce // tint // other stuffs

04-29-2025, 08:03 AM	#7
SOCAL.M6.ZLE Having FUN in the SUN... Drives: 2022 M6 ZL1 1LE Join Date: Jan 2022 Location: San Diego CA Posts: 2,190	Like others have said... based on GM's recommendation you are very late for your first change, and my results were similar for my first change at 500 miles once the gears are broken in, and then at by 1,500 miles things looked alot better. Changed once again at 5k miles and the drain plug was alot cleaner. That said, I am confident your next one will look alot better __________________ 2022 M6 ZLE: GMS Stage.III KONG X.PORT Package + DMS Lid + GMS Rear Bumper Belly Pan + GMS Hood Bracket + GMS Flex Fuel Package + MONSTER Triple S Clutch + XDI.50% Injectors + CLICK FOR BUILD LIST or www.GRIFFIN-MOTORSPORTS.com = 915rwhp 850rwtq + E60 + 15psi

04-29-2025, 08:15 AM	#8
JSH Drives: '20 ZLE Join Date: Jun 2020 Location: Mile High Posts: 4,195	The manual says 30,000 to 45,000 mi so I'm actually early haha. Anyone know the torque specs for the plugs. Seems like 25#? I'm going to put two new quarts of fluid in there today __________________ 2020 ZL1LE A10. LME LT4 390 short block, LME CID Heads, Kong E2650, FBO. 15" conversion, MT ET Street R 325/15. 100 octane: 1045hp/1055tq. 100 octane + Meth (1x10+): 1117 hp/1067 tq

05-01-2025, 10:24 PM	#11
wakespeak Drives: 2020 ZL1 1LE Join Date: Sep 2012 Location: Austin, Texas Posts: 1,420	Normal for that many miles I would say. I change mine after every track event. Just snug the bolts until they stop with a socket wrench. No need to put any muscle into it. __________________ 2020 ZL1 1LE [Moroso SC Expansion Tank, otherwise stock]

04-28-2025, 11:49 AM	#3
Mark R Drives: 2018 ZL-1 Join Date: Jan 2018 Location: Albuquerque Posts: 1,010	You are pretty late on the diff fluid change. I would change it again in a couple thousands and see what you get. It's likely just all the normal stuff from the first 16,000 miles.

04-29-2025, 06:41 AM	#6
clg82 Banned Drives: 2020 Camaro ZL1 Join Date: Oct 2020 Location: Texas Posts: 1,724	Totaled.

04-30-2025, 06:50 AM	#9
WhiteMale Drives: 23 ZL1 A10 Rapid Blue Join Date: Aug 2020 Location: MO Posts: 2,260	Looks like every other first and or second diff oil change that I've done and seen others post.

05-02-2025, 07:26 AM	#12
Patriot Motorsports USA Drives: 2021 ZLE, C5 Z06 6.0L Procharged Join Date: Mar 2023 Location: South Carolina Posts: 578	For the miles, that is early. Good thing your eLSD has the magnetic plug!! I would recommend changing it far more frequently as it goes from "Open to Fully Locked" in .03-seconds, so you can imagine the force it takes to do that and the gears, clutch plates and such can take a beating! Just change it with every oil change for a while and you will see it stay clear soon. I bought the 5-gal pail from Amsoil with their hand pump and it makes changing the rear diff fluid a five minute ordeal.

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