Denali - Front & Rear diff service...

[vjr021]

Anyone done this on their ride??? I am getting conflicting numbers on the amount of gear lube in the diff's I want to do Royal Purple, but I am told it take 5-6 liters per diff... @ $20 each L that get expensive, fast.

Also the dealer wanted $149 for each axle, they said they flush out the diff, anyone know what else they do to justify $150?

thanks!

 

[Sasquatch]

I contacted royal purple about their products and this was the reply i got.


We recommend the RP MaxGear 75W90 part # 01300 for both the front and rear differential. Not sure why GM would do that – as if the back diff specs a 75W (or SAE 75 Winter grade (the W does not stand for weight but ‘winter grade’) with low temp flow performance why wouldn’t you want that for the other end of the truck? Both fluids are SAE 90 weights at operating temp.

Front takes 1.8 quarts and the rear 2.75 quarts.

 

[denalianyone]

I see the fill plug for the rear diff but can't locate the drain plug. According to my Haynes manual, it is located underneath the casing but I don't see it.

 

[amaz]

Not every rear diff have a drain plug. In that case you have to take the diff cover off or suck the old oil out from the fill plug hole.

 

[ofivekon]

Not every rear diff have a drain plug. In that case you have to take the diff cover off or suck the old oil out from the fill plug hole.

On that note, anyone recommend a good fluid pump? Manual, electric, or compressed air driven... would be nice if it had multiple applications (ie. brake fluid, differential fluid,... etc.). Thanks in advance.

 

[SQNALI]

I have a vacuum pump from MAC tools that works alright - just takes forever. Electric pumps work better but get realllllll hot. For any differential where the cover is accessible you're better off just taking the cover off and re-sealing it -- youll get allmost all the old fluid out and a chance to inspect your gears and likely save time.

As to the initial post - A "DIFFERENTIAL FLUSH" (at any shop) Involves sucking the old fluid out and filling it up with new. -- Yes this is a money making industry.....
)

 

[91RS]

Unless you know how to do it, you will not get all the fluid out of the rear diff with a fluid sucker. You need to take the diff cover off if you plan on doing it yourself.

And I don't know about other dealers (and especially the half-ass quick lube places), but we sell a differential service (not a flush) which is removing the old fluid and replacing with new. It is easy if there is a drain plug, but not so much if there isn't. On these trucks it is a little difficult to get past the ring gear to get all the fluid out on the rear diff. Our price is $120 for the BG service by the way and the fluid itself costs about $90 of that price.