Check those diff's!

birdman7389 · April 15, 2012

We have a '10 Silverado extended cab Z71, and while it is my DD, it tows around 6000lb of toy hauler on occasion.

The truck has about 25K miles on it, and about 2500 of those were towing the big trailer.

I'm moving across the country this summer, down to Alabama, and will tow the trailer. I wanted to go ahead and put a big trans cooler on, and change out the differential fluid for good measure.

I was tempted to just do the rear, as that is the one that sees all the pressure and heat of towing, and I have not used the 4wd all that much. I went ahead and did fluids on both, and I'm glad! The rear was fine, just normal looking fluid and some particles on the magnet, but the front was MILKY. Water got in there somehow. It does rain lots here in San Francisco, and we have a few trips in the snow, but I've never gotten too crazy with it.

I'll be changing that front fluid again here in a few thousand miles for good measure and to make sure no water got in there.

I guess my point is that you have NO CLUE what shape your fluids are in, regardless of age or miles. Better safe than sorry!

BTW: The rear diff on mine had one of those nice rubber/metal gaskets. No junky paper ones or RTV to mess with.

SouthCo · April 15, 2012

Good advice. Always good to do the front and rear diffs and transfer case at least every 15K miles depending on how hard you use it.

jaredlucky16 · April 16, 2012

Are u sure it was milky or was it just cloudy from all the metal in it like usual

00Silverado4x4 · April 16, 2012

Are u sure it was milky or was it just cloudy from all the metal in it like usual

When I did my diff's here a few months ago, the front was definitely cloudy thankfully not milky. I don't think they had ever been done before so I was glad I didn't wait much longer to do them.