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Probably not the first but I just added 1 Qt. of dexron LS gear oil (GM P/N 88862624) to my 2016 Z51. Since the total capacity is less than 3 Qts. down one can't be good
Jack up the rear or on ramps if you have them. Remove the top plug of the rear. If after removing the plug (a 3/8" rachet end with a small extension works just fine) if no fluid leaks out stick your finger in the opening and try to feel where it is.( If it does not leak when you remove the plug you need fluid)
Caution.. the plug is right near the hot exhaust , be careful not to burn yourself. Removing the plug can be a pain ,be patient.
Capacity is 2.9 Qts. If its low, you probably need a quart or less. Your local GM dealer has Dexron LS fluid Gm part # 88862624. About $10 a qt. No need for special clutch plate additive. The GM fluid already has it in it.
[QUOTE=Maxie2U;1592364888]Do you know if this a problem from the factory, under-filling the fluid?[/QUOT
Have seen some threads on this in recent months, that's what had me check it.
So you jacked up only the rear end, canting the car forward. Then opened the fill screw on the back side of the diff and added a quart. You've overfilled your diff.
You can access the fill port with the car on the ground. Just shimmy under. 'Full' is even with the fill hole to 13mm below it. Tilting the car forward by only jacking the rear up will not allow you to assess the situation well. And filling in that position until it overflows will again just overfill it.
Last edited by spearfish25; 06-06-2016 at 01:33 PM.
Jack up the rear or on ramps if you have them. Remove the top plug of the rear. If after removing the plug (a 3/8" rachet end with a small extension works just fine) if no fluid leaks out stick your finger in the opening and try to feel where it is.( If it does not leak when you remove the plug you need fluid)
Caution.. the plug is right near the hot exhaust , be careful not to burn yourself. Removing the plug can be a pain ,be patient.
Capacity is 2.9 Qts. If its low, you probably need a quart or less. Your local GM dealer has Dexron LS fluid Gm part # 88862624. About $10 a qt. No need for special clutch plate additive. The GM fluid already has it in it.
You may want to check it again, but with the car level. If you lifted the rear of the car, but not the front, you likely overfilled it now. Try to keep the car level when checking any fluid levels. Also, make sure to run the car in second gear slowly to 10MPH (while on lift) for a minute, then turn car off and check fluid level again (while level). This assures that the coolers are filled.
Last edited by only9balls; 06-06-2016 at 02:14 PM.
My 2014 was also about 1\2 -inch below the hole from the factory, but according to GM that is within the acceptable level. I went ahead and filled it up to the bottom of the hole anyway.
Mine had no leaks, just underfilled at the factory.
I checked mine it was low so I just chg it and the auto trans out. But the trans was good on level, but the rear end was low I never did add only chg it out.
But from the amount I got out to what I had to put into it to fill was a good amount. Mine also a 2014. Robert
So you jacked up only the rear end, canting the car forward. Then opened the fill screw on the back side of the diff and added a quart. You've overfilled your diff.
You can access the fill port with the car on the ground. Just shimmy under. 'Full' is even with the fill hole to 13mm below it. Tilting the car forward by only jacking the rear up will not allow you to assess the situation well. And filling in that position until it overflows will again just overfill it.
My driveway slants downward. I initally ran the rear on to ramps. Vette was almost level, not perfect. I just checked it on a perfectly level garage and total of approx. 3 oz. drained out. So for a total capacity of 2.9 Qts (93 ounces) I had to add approx. 32 ounces, so it was down by 1/3.. Thanks for you input. It was worth the time to double check.
I went to check rear diff oil on my nonZ. Dumb a$$ me pulled the drain plug my mistake and lost about a OT or so of lube before I could get the plug back in. Looks like the rear takes about 2.9 qt of dexron LS. Is the bleed method only for the Z51? Or can I go to the dealer and buy the oil and just top it back off? I will also get a OT pump to make it easy.
I went to check rear diff oil on my nonZ. Dumb a$$ me pulled the drain plug my mistake and lost about a OT or so of lube before I could get the plug back in. Looks like the rear takes about 2.9 qt of dexron LS. Is the bleed method only for the Z51? Or can I go to the dealer and buy the oil and just top it back off? I will also get a OT pump to make it easy.
By the way, I tried one of the cheap bottle pumps and it broke before I even got the tube filled, so I drilled a couple of holes in the cap, and used my air compressor and trigger handle to push the fluid out of the bottle and into the differential... No mess and you can control the level easily. Note, air pressure goes on TOP of the fluid, and forces the fluid down and out the fill tube, so the fill tube must go to the bottom of the bottle. Since there is only air on the top of the bottle, any leaks are only air.
Not a bad idea to go ahead and drain and refill since mine had significant deposits on the plug at 8,000 miles.
By the way, I tried one of the cheap bottle pumps and it broke before I even got the tube filled, so I drilled a couple of holes in the cap, and used my air compressor and trigger handle to push the fluid out of the bottle and into the differential... No mess and you can control the level easily. Note, air pressure goes on TOP of the fluid, and forces the fluid down and out the fill tube, so the fill tube must go to the bottom of the bottle. Since there is only air on the top of the bottle, any leaks are only air.
Not a bad idea to go ahead and drain and refill since mine had significant deposits on the plug at 8,000 miles.
06-06-2016, 11:56 AM
Check your rear end fluid
I cant see it just disappearing.
I checked mine it was low so I just chg it and the auto trans out. But the trans was good on level, but the rear end was low I never did add only chg it out. 
