HOW-TO: Drain and Fill Your Rear Axle

[CoolBlueSS]

Yeah dude that's HOT for a tranny, like cut-your-tranny-life-in-half kind of heat, get the largest tranny cooler you can find, I shoot for temps in the 160-180 range.

 

Rear end - yeah when the paint is flaking off that's intense.  You are right, you have some really serious towing - 20-mins WOT is a monster pull.  I agree with what you are thinking, a finned cover, more fluid capacity is a must in your application.  I would also buy some temperature strips, they are a little pricey @ $3 apiece but it will tell you exactly what the rear-end temp is, Here's a link to some.  Using a temperature label you can check later and see the hottest that the surface got 

 

Mr. P.

<{POST_SNAPBACK}>

 

Thanks for that link, I think I might get some of those.

 

FWIW, during towing, my 2006 VHO outperforms my friends 2005 3/4-Ton 6.0 Silverado HD in every way, mpg, power, ride, etc. and his trailer setup and weight is almost identical to mine. His trans temps are about the same as mine. I would like to temp-strip both of our diffs before are next Vegas haul.

 

EDIT: I have not checked the temperature yet.

Does it just look like a bad paint job?

 

<{POST_SNAPBACK}>

Yikes!! That sucker got hot. Definitely I would use a finned rear cover, and/or a rear diff cooler.

[06VHO]

Mr. P,

I made that haul thru Baker to Vegas again. Take a look at these pics.

I put two different range temp strips on the bottom of my diff-housing.

Either the 219f or the 230f was defective, as the 230f turned black and

the 219f stayed white, Hmmm!!!!! I know it did not get to 270f though.

That is with the new finned aluminum cover and the Lucas Synthetic.

I still would like to know how hot it got, before the new cover & lube.

 

 

 

[misterp]

Mr. P,

I made that haul thru Baker to Vegas again. Take a look at these pics.

I put two different range temp strips on the bottom of my diff-housing.

Either the 219f or the 230f was defective, as the 230f turned black and

the 219f stayed white, Hmmm!!!!! I know it did not get to 270f though.

That is with the new finned aluminum cover and the Lucas Synthetic.

I still would like to know how hot it got, before the new cover & lube.

...

Neither strip is defective; the cover exceeded 230-degrees (maxed-out the first strip) but never got up to 270-degrees. These strips are very accurate, like within 1.5% tolerance; I'd say your diff is maxing-out between 235 and 265, and that's still hot but at least it's tolerable on synthetic oil. And it sure as hell beats cooking the paint right off the cover! Check the literature on the Lucas Synthetic and see what its life is like at that temp, if the product is still thermally stable at that heat then you are ok. It would be nice if you could chill it down another 20-degrees but it will certainly be cheaper to just live with the situation (after all it's only during towing) it and change fluid more often rather than go to the expense/effort of installing a differential oil cooler.

 

Mr. P.

[kling]

Thanks for that very informative post... now i know how i can drain and fill the rear of my volkswagen axle.

Hope you'll have more how-to's to post

[wkeil]

Where can I get a new gasket, and whats the part number for it? My truck is an 06.

[misterp]

Where can I get a new gasket, and whats the part number for it? My truck is an 06.

Any auto parts store should have one in stock, this is a very common gasket.

 

Mr. P.

[r8rs4lf]

Good post!

 

I plan on doing this today since I noticed a minor leak in the rear end.

 

I do have a question though. Do I need to add a "friction modifier" when I go to refill the rear end? On my old '88 Blazer, I would always add this to it so one day I went out and bought a box of it.

 

This is the brand of what I have. The additive I have doesn't seem to be on their site.

 

NEO Synthetics

[Krambo]

Using the friction modifer is debatable either way. I chose to NOT use it and am happy with the results thus far. Although, I used synthetic gear lube...

[misterp]

Out of habit I added friction modifier to mine, then zippy let us know that in the G80 you're not supposed to do that, it gums up the clutches or something. I've had no problems.

 

Mr. P.

[Erwin8r]

Just one more thing to note for those with higher mileage and/or trucks in "corrosive" states--before you drain your diff fluid, make sure you can get the fill bolt undone. It would really suck to have all of your fluid out and no quick way to refill your diff. Thanks for the write-up, Mr. P. I'm doing all three this weekend (seeing if I can get the GM blue stuff tonight).

[tulanejp]

Thanks for the write-up Mr. P! Did this today with no issues. After reading this, squirted the fill screw with WD40 yesterday. Made removal today easy. Thanks again. By the way, I used that fill tube doo-hicky mentioned in the writeup for changing the front diff. fluid. Man, is that thing handy!

[misterp]

Thanks for the write-up Mr. P! ...

Anytime

[superchevything]

Just did mine thanks for the how to Mr.P

[Reese Byerrum]

Is it okay to use Royal Purple Diff oil?

[T-Bag]

Is it okay to use Royal Purple Diff oil?

 

I do....