Rear Diff additive?

[dino688]

Read the other day somewhere that the G80 likes to have an oil additive. I currently have Mobil1 75W-90 Synthetic in there and want to add some Trans-X PosiTrac gear additive. Is this advisable?

[hvac1000]

Do exactly what your owners manual says to do. Lot less trouble that way.

[budhayes3]

I don't believe that any additives are necessary for the G80 as long as you're using a good synthetic gear oil.

[MS3DALE]

I would strongly advise NOT to add any additives at all.

The G80 dosen't need any and GM dosen't recommend any.

I have seen quite a few G80's here at the dealership ruined because of someone adding an additive.

[asilverblazer]

Synthetic is all that's recommended.

[bigdogxx]

I took mine in for it's first oil change at a little over 500 miles and my mechanic found that the rear end was low a quart of oil. He said that no damage could of taken place but thought i would ask here since some seem to be mechanics for chevy.Is this something i should worry about or since it only had 500 miles on it should i be ok?I cant believe though that these fluid levels are not checked at the factory then again before the dealer sells it off!

[MS3DALE]

Actually the fluid is low from the factory.Its supposed to be 15 to 40mm below the fill plug hole on 1/2 tons with the 8.6 rear axle, 0 to 10mm below the fill hole on the 9.5 and 10.5 rear end,0 to 4mm below on the 9.75 rear end and 17 to 21mm below the fill hole on the 11.5 rear end.

[bigdogxx]

Actually the fluid is low from the factory.Its supposed to be 15 to 40mm below the fill plug hole on 1/2 tons with the 8.6 rear axle, 0 to 10mm below the fill hole on the 9.5 and 10.5 rear end,0 to 4mm below on the 9.75 rear end and 17 to 21mm below the fill hole on the 11.5 rear end.

 

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Well not sure what size the pumpkin is but it is a 1500 z71 w/the g80 locker.The mechanic said there should be 4 quarts in it and only found 3. :confused:So is there to much in it now damm im all confused, i was always told that you fill till it starts to seep out of the fill hole.

[asilverblazer]

You will probably be ok, Mine held about 3.5 before seeping out the fill hole. When it diod I put the plug in and called it good. Having 3 in it to begin with seems closer to the right amount rather than 4 which seems to be to much.

[Bish]

When I change mine, it only takes a little less than 2.5 qts to fill. I also set the level using a small hex key to make sure it is below the fill hole and within spec. I've heard over-filling can cause your pinion seal to leak.

 

I don't think you caused any problem.

[bigdogxx]

Well i just called my service dept. and they said to fill it till it's starts to seep out the hole which is what i always thought so i guess my mechanic did the right thing by filling it up, and if not oh well thats what the warranty is for.

[RyanbabZ71]

The mechanic said there should be 4 quarts in it and only found 3

 

How did he know it was a quart low? Did he drain it completely? That would be the only way to accurately know

[MS3DALE]

Well i just called my service dept. and they said to fill it till it's starts to seep out the hole which is what i always thought so i guess my mechanic did the right thing by filling it up, and if not oh well thats what the warranty is for.

 

 

 

 

 

I think I would find another service dept. because they told you wrong,believe me they are incorrect.

[bigdogxx]

Well i just called my service dept. and they said to fill it till it's starts to seep out the hole which is what i always thought so i guess my mechanic did the right thing by filling it up, and if not oh well thats what the warranty is for.

 

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I think I would find another service dept. because they told you wrong,believe me they are incorrect.

 

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Just a thought though, how do you know how many mm away from the fill hole you are when there is no way to measure it?

 

And there is not much i can do when every mechanic i talk to tells me the same thing fill till it seeps out.If there is no lit. on the net that says it in writing that it needs to be so and so far away from the fill hole theres nothing they will do for me.

[Bish]

Well i just called my service dept. and they said to fill it till it's starts to seep out the hole which is what i always thought so i guess my mechanic did the right thing by filling it up, and if not oh well thats what the warranty is for.

 

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I think I would find another service dept. because they told you wrong,believe me they are incorrect.

 

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Just a thought though, how do you know how many mm away from the fill hole you are when there is no way to measure it?

 

And there is not much i can do when every mechanic i talk to tells me the same thing fill till it seeps out.If there is no lit. on the net that says it in writing that it needs to be so and so far away from the fill hole theres nothing they will do for me.

 

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Use an L shaped hex key. I have a peice of masking tape on the end with the min and max marks. I dump 2.25 qts in then a squeeze at a time until it falls in line. Once you try it, it becomes very simple. It would be better if you could just fill until it overflows the fill hole but there must be some reason for it.

 

Also, it states the fill spec both in my manual and on a big plastic tag attached to the diff at the fill hole. If you are piutting fluid in, you cannot miss the tag.