Dealership recommended it because it's got 105k miles and i bought it used. They charge $126.99 per differential and I have a 4x4 so thats nearly $300 right there.

What ya'll think? Should I have another place around town do it?

 

Drain and refill with synthetic. Forget the flush, total waste of $$$.

 

I agree. Drain and refill with quality synthetic oil.

 

can I do this myself, or should I have the dealership do it?

What are the differences in flushing it and draining it and replacing with synthetic?

 

Well to be honest not much other $250. The dealership isn't going to wash out the diff's. There are 2 ways to flush. One way to flush them out is taking them off the truck and slosh some more clean oil back and forth then drain and wipe it out. The other way is to drain it add new oil drive it for a bit then drain it again. The bearings need the oil to be moving through them to actually flush any particles out. This is a pretty simple job to do. Just like changing oil but without a filter.

 

the front axle has a drain and fill plug. pull both plugs and drain out 2 quarts. if you blow air thru the top plug, you will get more residue out of the drain plug. reinstall the bottom plug and put 2 quarts of 80-90 wt gear lube in the front.--- the back end is different, no drain. you take the oil pan off the back side. has about 12 small bolts holding it on. take them off and the oil goes all over the floor ( try to catch it in a pan). wipe out the inside, put the cover back on with RTV gasket. put 2 quarts of 75w 140 synthetic gear lube in the back. put in 7 ounces of the friction modifier if you have limited slip. not a bad joob if you have some experience and mechanical abillty. find a buddy who has done it and you can do both ends in 2 hours. regular gear lube cost $4 quart. the synthetic can be $10-20 quart depending on the brand.

 

the service person said the tech just hooks it up to a machine and it does all the work for him. I'm guessing it sucks all of the oil out? Kind of like when you do an oil change and they use the machine to suck the oil out instead of letting it drip. Supposedly the machine gets it all out whereas draining leaves some in there.

 

Hello LSUtigers Here is my thought on the dealer and you getting flushed so to say. There is no machine that is going to get into each area of the differentials. The front differential is pretty much a simple drain and refill. There really isn't much else you can do to it. I don't know if yours will have a magnet on the drain plug but I think it will. That has trapped and collected most of the ferous materials created through normal wear and tear and usage. Just be sure what kind of oil you are taking out of it. Petrolem base or synthetic. When I bought my F150 4x4 I got it with a chewed up set of spider gears at the axle ends so dropping the oil was a must as part of my repairs. You should do this flush yourself. There really isn't much to it in your situation. I do however suggest that on the rear differential while you have it opened up that you remove the ABS sensor located on the outside drivers side top of the case and remove all of the metal that has gathered on it. It may save you later from a fault code in your antilock brake system. I pulled mine out and I saw smaller wear filings and larger bit of metal collected to it. I re-installed synthetic lube to mine as well. You can dispose of the oil for no charge at most quick lube service stores. As far as that goes...Hey, you may be able to get them to change the fluids in both differentials too... Joe

 

If you read "The Manual" it states that the differentials are lubed for life, unless they've been submerged in water. It never hurts to change the fluids though. Do it yourself, exactly as Steve (ill) described. Using the proper gear oil for front and especially rear. There's no reason you would not be able to do this yourself. The hardest part is squeezing the RTV tube hard enough to get a nice bead. (For me anyway)