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misterp

HOW-TO: Drain and Fill Your Front Axle

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Changing your front differential fluid is pretty-much dirt simple, no prior automotive experience is required, just the following tools and supplies:

 

* a drain pan;

* a 13mm wrench or socket/ratchet;

* a 15mm wrench or socket/ratchet;

* 2-qts synthetic 80W-90 GL5 gear lube;

* pour tube or gear lube pump;

* small shop rag;

* adequate lighting;

* (optional) a creeper or tarp to lay on.

 

Just like the G80 rear axle - very high temperatures are developed in the front axle during its initial 300-500 miles of life as the ring and pinion break in (over 350-degrees); also, debris from manufacture will be washed down into the fluid. In these first miles of life avoid towing, high loads, and high-speed extended driving until the ring and pinion have seated and axle temps fall to normal. Due to this high initial break-in heat a gear lube change is in order; draining and refilling with synthetic fluid after initial break-in can be considered 'lube for life' but most conservative mechanics recommend draining and refilling at 40K to 50K intervals, even earlier in dedicated tow/severe duty vehicles.

 

Failing to drain and refill your front axle after break-in can result in high noise operation, howling, and/or outright bearing failure as (1) the debris from manufacturing continues to circulate inside the axle housing and tears up bearings and seals, and (2) the lubricity of the factory filled synthetic gear lube is greatly compromised by break-in heat.

 

To begin, park your truck on a level surface with good lighting and follow the illustrated how-to below:

 

01_Plugs.jpg

 

02_Drain.jpg

 

03_Check.jpg

 

04_Tube.jpg

 

05_Fill.jpg

 

That's it, stow your tools! After your first few miles of operation check for leaks and lowered fluid level (it may have dropped as much as 1/4-qt, or maybe not). Regardless of the service interval you choose (40K, 50K, or never) check at every oil change for leaks and pull the fill plug every 7500 miles to top-off the rear axle fluid.

 

Mr. P. :)

Edited by Mr. P.

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MisterP,

 

another great "HOW TO" post. I'm going to be doing both the front and rear axles this weekend per "your intructions" good job :thumbs:

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MisterP,

 

another great "HOW TO" post.  I'm going to be doing both the front and rear axles this weekend per "your intructions"  good job :thumbs:

Thanks - you're not going to be needing any Scrotum Scub, are you?! :jester:

 

Mr. P. :)

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Hey Mister P another great how to. Hey can you teach my guys a thing or two. Its hard to find a good tech.

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Awesome how-to, looks like another wonderful weekend project!

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I'd rate that a 2 on a difficulity scale of 1 to 10, only because you've got to get a little horizontal on the ground!

Sounds easy enough, but a question about the rear ....

 

My local Oil quick change place, (very reputable around here) insists that the chevy rear ends run a little low on lube when checking. I was told I'll have problems if I try to run it topped off. Is this because of the higher running temperature? I naturally would prefer it was "full" with lube for cooler running temps, and proper lubrication, but I trust my oil change man, he's very informed and cares about his clients vehicles.

 

What's the overall concensus on the board about this matter?

 

Thanks guys.

 

Great tutorial Mister P! :thumbs:

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Mr P or anyone else who knows..

 

All i can seem to find is Synthetic 75-90 (amsoil or Mobile 1) Is it critical to use the 80-90?? thanks in advance :cheers:

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Mr P  or anyone else who knows.. 

 

All i can seem to find is Synthetic 75-90 (amsoil or Mobile 1)   Is it critical to use the 80-90??  thanks in advance :cheers:

Technically 75-90 is made from a tad thinner base stock than 80-90 (75- vs. 80-), but if using a synthetic base combined with a good additive package (-90) it will flow similarly at operating temp. I used the Mobil1 synthetic 75-90 GL5 in my SS, and both the front and rear differentials are running quieter than before.

 

Mr. P. :)

Edited by misterp

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Thanks Mr P .. I just wanted to be sure before i purchased the 75-90. Thanks for your how to post.

 

Thanks to whoever gave out the rear differential gasket part number also. Advanced had 2 in stock and I dout very seriously i would have gotten the right part without knowing this ahead of time. A little research goes a long way. thanks again guys :cheers:

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Do you need to add any type of friction modifier to the front and rear axles? Just wonder since I have had to in my fords and dodges. :jester:

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