OK campfire mechanics......

2001 Dodge truck non limited slip differential.

I bought the truck about a year ago and am thinking about changing the fluid in the rear diff.

I have watched a few videos of people doing this and some of them flush out the diff with brake cleaner. Others say that is a no no.

I am almost positive that the fluid in my truck has never been changed and I would like to hose it out with a can or two of brake clean when I get it apart.

So is it the wrong or right thing to do.....is there anything in there I could harm with the solvent if I let it dry really well before reassembly?

I wouldn’t. There is nothing to be gained in doing so. If you get enough brake clean into the pinion bearing or carrier bearing, it could wash them too dry & it is not necessary. Residual lube is gooder than no lube. If it means that much to you I would wipe it out with towels or rags.

Dont think I would use break clean.


If I had to wash out a gear case I would use a Stoddard solvent.




That was if I had to wash it. Otherwise I would wipe it out as best I could and refill.

What does the fluid in the diff look like now? If it looks reasonably like gear oil then I would drive it to get the oil hot then pull the cover and let it drain for a few minutes. New gasket and/or silicone the cover back on and done. If the gear oil looks like tar (seen it before) then maybe some sort of solvent flush is in order, then refill, drive gently a few miles, then dump it again and refill with correct oil. Make sure the vent is clear too while you're under there.

I just drain them and fill them. The limited slip started hanging up in my truck last year. Wouldn't disengage sometimes if I spun a bit. Changed the fluid and back to working fine. 100000000000000000000000000% make sure the fill plug comes out before you drain the fluid. In a bit of a pickle if you drain it and cant fill it back up. Years ago I had that happen on a beater truck. I had to drill a hole in the back cover to fill it and ran in a fender bolt coated in silicone to plug it.

I thought this was going to be a setting a ring gear question or something difficult.

Don't sweat spraying it out, just wipe it out like Jim said . Be careful not to over tighten the bolts putting the cover back on. Filling it back up is the worse part sometimes if you don't have access. Most of us use some kind of hand pump to get in there. Probably no issue on your truck. Make sure there is enough in there regardless of what the internet says is the correct amount by volume. 1/4" or less to the fill plug. Level with it is normally correct. Add the limited slip additive if required or buy the fluid that has it.

If you’re still insistent on flushing it. Just buy and extra jug of fluid. Squirt that in there with the drain plug out.

Pull one or two bottom cover plate bolts and let the old lube drain, then reinstall them and top the housing off with Diesel fuel. Jack the rear end up and support it on jack stands (both wheels off the ground). Fire up the truck, put it in Drive, and walk away for 30 minutes or 3 beers, whichever is longer. Drain and refill- - - -no need to even pull the cover plate that way! Jack up one wheel higher than the other to let the new lube find its way to the wheel bearing on one side, then the other, before driving.
Jerry

This or drain old out put new in and run it 2000 miles and drain it and put new in again.

Don't do it.

I recently did my vehicles. The advise to first remove the fill hole is spot on.

I trim the nozzle of the gear lube bottle and push a length of tubing on. Auto parts store will have lube and tubing. Squeeze the bottle to raise the fluid. You won't be able to empty the bottle but merely refill and give it another go. Far cheaper than one of those pump devices.

I always drain and refill. Only pull them apart if there is an issue. Stoddard fluid is what I used for cleaning parts.

Drain it, fill it. I do mine every 30,000 miles. You are wasting your time washing it out, maybe screwing up doing it.

Don't poke a hole in the bottom of the gear oil bottle and use an air hose to blow it up and push oil through the hose.
Won't say how I know....

Yeah your friend/cousin/brother screwed up didn't he!

Keep in mind when refilling standard gear oil and synthetic and synthetic blend do not always mix study your fluids well do it right. Mixing the wrong kinds together can cause just a big gummy ball and you will trash the rear end shortly after

Okay fellas, drain and refill only it is. If it looks really bad I'll just change the fluid again shortly.

Thanks guys!

I was once told by an expert......…….........NEVER wash a bearing! And while some folks do, the worst thing you can do is blow it out with an air hose and let it spin!

You have made the right decision.

Drive it before you change it so it’s all stirred up.

Just drain it, wipe out the bottom of the housing, refill it and instead of relying on YouTube videos for information get a shop manual. There should be a magnet in the bottom of the housing but if there's not get one. I've never had a vehicle that didn't have a magnet in the housing but I don't know about your 2001 Dodge.

It is ok to wash bearings if you add 10% oil to solvent so they never dry out, per MD helicopter maint manuals and training.

If it has a limited slip( posi) make sure the oil is for limited slip. Additives that are added for limited slip work! Check with a dodge dealer to find out if synthetic oil was used at the factory! For those that have a limited slip that isn't releasing, after an oil change( with correct oil), drive to a field and start doing figure eights. This will usually release the clutches, and you are good to go!

Drain and fill ,KISS! Be sure to use the right lube. If it's k y find a different rear and fill it.