Rear Axle Lube Level?

[67mike]

Going to be changing the rear axle gear lube soon on my Vortec Max with the 9.5 (AXN) rear axle housing. The manual says to fill 0.06”-1.6” below the fill hole.

 

My question is why is there such a variation in this spec? A difference of 1.5” is quite a bit in my opinion. So what is the ideal fill height? The difference of 1.5” must affect the amount of lube the bearings and seals see. Some say too much lube makes the seals leak, others say too little dries the seals out.

 

I would like more of a exact spec to follow.

[Stevens03]

I've always stuck my pinky in the hole, and if it's wet, its good, if its not, I add...

[Gone Again]

Going to be changing the rear axle gear lube soon on my Vortec Max with the 9.5 (AXN) rear axle housing. The manual says to fill 0.06”-1.6” below the fill hole.

 

 

My question is why is there such a variation in this spec? A difference of 1.5” is quite a bit in my opinion. So what is the ideal fill height? The difference of 1.5” must affect the amount of lube the bearings and seals see. Some say too much lube makes the seals leak, others say too little dries the seals out.

 

 

I would like more of a exact spec to follow.

1/2 to 3/4 inch below the hole will keep you out of trouble.

[txab]

Going to be changing the rear axle gear lube soon on my Vortec Max with the 9.5 (AXN) rear axle housing. The manual says to fill 0.06”-1.6” below the fill hole.

 

 

My question is why is there such a variation in this spec? A difference of 1.5” is quite a bit in my opinion. So what is the ideal fill height? The difference of 1.5” must affect the amount of lube the bearings and seals see. Some say too much lube makes the seals leak, others say too little dries the seals out.

 

 

I would like more of a exact spec to follow.

There is only 1" difference. Look again, it says .6" not .06". Split the difference. It's not friggin rocket science. Set it at about 5/8" and all will be well

[dlstewart01]

Disclaimer: Do not listen to me as this is just my own experience.

 

Five years ago I purchased a mag-hytec rear diff cover for my 2005 sierra 10 bolt rear. it has a magnetic dip stick and top fill plug. If you go by the marks on the dip stick the gear oil level will be at the top of the factory fill hole or about 1/2 to 1 inch over the recommended fill level???

 

I called the engineering dept at Mag-hytec and ask them about this. They said: They had done very extensive testing and in their opinion GM had speced the rear end to be under filled and this led to over heating and premeture failure. I asked about leaks and they said in their testing that no leaking had ever occured.

 

Well I chose to listen to the engineers at Mag-Hytec take a chance and run the higher level. I tow a camper and wanted the greatest level of protection available. In five years I have had NO leaks. The diff runs very cool. When I periodically remove the the magnetic dip stick, there is hardly any metallic particles stuck to it.

 

Like I said this has been my own experience, so if you should attempt this you are on your own.

 

Have a very pleasant day,

 

Don

[Black02Silverado]

I would use an allen wrench and measure down from the fill hole 1/2" and call it good. That is what I did on my 02 silverado's rear diff. 98k and no issues.

[ken1mod]

We started filling axles 20 years ago to a level below the fill hole. Axle seal failures were driving us crazy until we did this. Never a problem under abusive conditions. Millions of miles.

 

Ken

[dlstewart01]

Until this truck, I have always filled them till the fluid ran out of the fill hole...I have 50 years of driving and well over a million miles with NO seal leaks...Just my experience.

[67mike]

After reading the replies i could of swore my manual said 0.06"-1.6". I went back to look at it and it most definitely reads 0.06 in my 2007 owners manual.

 

This of course must be a misprint because it reads (15mm-40mm) after the inch measurements

 

Curious if other 2007 silverado owners manuals read the same?

[txab]

Must be, because the Service manual shows .6". As stated in the previous post, anything from pouring out to 1/2 down and you're good to go

[nickvrebel]

excerpt from the 2009 manual:

8.6":

For all 4.3L, 4.8L and 5.3L 1500 Series applications,

the proper level is 0.04 inches to 0.75 inches

(1.0 mm to 19.0 mm) below the bottom of the filler

hole, located on the rear axle. Add only enough

fluid to reach the proper level.

9.5":

For all 6.0L and 6.2L 1500 Series applications,

the proper level is from 0.6 inches to 1.6 inches

(15 mm to 40 mm) below the bottom of the filler plug

hole, located on the rear axle. Add only enough fluid

to reach the proper level.

[twavor]

I've always stuck my pinky in the hole, and if it's wet, its good, if its not, I add...

Good advice....

 

Travis