Do I really have to change rear differential fluid?

[martyi]

I change my own oil and filter but never had to do a rear differential on any vehicle I've owned for the last 40 years. However, the maintenance minder on my new Honda Ridgeline truck will soon show the service due notice for a drain and fill of the differential fluid and need some tips on DYS since I'm not paying Honda dealers $130 to do this.

First, why do I have to change it in the first place? The manual says that if I tow or do a lot of slow speed, off road driving I need to change at 7500 miles and then every 15000 thereafter. I do neither so I am going only by the on board monitor. What happens if I don't change it? I know it has clutches and stuff back there and that may be the reason it is considered an important maintenance item.

Second, I know where the drain/fill plugs are back there but I heard there is a hand pump of some sort I need to buy to pump the fluid in. Can anyone give me recommendations as to a pump to get for this job? Thanks in advance.

 

[road_rascal]

You need one of these. I need one of these.

Rear diff service is easy, and I would do it if it was my truck.

 

[martyi]

Thanks, I'm wondering if PepBoys or some auto supply house would have something like this?

 

[Kestas]

Tip: If you have both a drain plug and fill plug, remove the fill plug first. It's harder to remove. In fact, sometines it's impossible for some to remove, leaving you with the embarrassing situation of having drained the fluid and no way to put the fluid back in!

 

[martyi]

Good tip, thanks!!

 

[blupupher]

If you have a drain plug, you don't need any special tools. Just do as Kestas said, remove the fill plug, put pan under diff, remove drain plug and let it drain. Replace drain plug, add correct new fluid (usualy to just below the fill plug), install fill plug and your done.
It is sometimes easier to get to the fill plug by jacking the rear of the vehicle so the axle hangs lower.

 

[Greaser]

It's best to remove the diff. cover the first couple of times.This gives you the opportunity to clean out the gears/bearings and housing with a cleansing oil (or break-clean)to remove gear break-in material before filling with clean fluid.The fluid evaquator is great to have (I have one and it works great)but only use this device after a couple of proper drain & fills (cover removal clean-out).

 

[porcupine73]

I would guess it is supposed to be changed because of metal particle contamination from wear, maybe oxidation if towing or other use really jacks up the temp in there, additive depletion, and maybe shear back of the gear oil, tho I don't know how much VII's are used, esp. in synthetics.

It was posted in another thread on here a while back that heating the drain plug and applying real bees' wax to the threads plug threads will then permit the plug to be removed if it's being really stubborn. I usually just use an impact wrench with an impact pipe plug socket with no problems and Kroil if the plug is being difficult.

 

[Kestas]

Make sure to put the plug back with teflon tape or a light coating of antisieze.

 

[Jim 5]

I'm guessing it has a drain plug. If it doesn't, then it's going to have a cover.

It is definitely worthwhile to change this fluid, and it's a satisfying job to do. Some good advice above.

My BMW dealership charges $100 for this service. The diff had a drain plug and a fill and I did it myself with redline 75w-90 for $10 in about 10 minutes. Way easier than changing the oil.

I would follow the intervals recommended by Honda. It is likely a really easy job.

 

[Rhymingmechanic]

A cheaper way to put the fluid in is to use the nozzle/cap that comes on most gear oil bottles. A piece of tubing or one of the many nozzle/tubing accessories sold at most parts stores might make things a little easier for just a few dollars.

 

[Winston]

You definately do not need a Mitivac to do this. Like Rhyming said the bottles with the pointy spout work well if you attach a piece of tubing to them. If you buy the Gallon containers you can buy a cheap pump ($6-8) that pumps the fluid out of the container, through a plastic tube and into the diffy.

One other tip. I fill a five gallon bucket with hot water and put the gear oil in it (for the front and rear diffy and the transfer case) for a half hour. Makes it real easy to get that fluid out of the bottles.

 

[Kestas]

I once tried using tubing as an extension for the nozzle. It kept slipping off and made an awful mess.

 

[1sttruck]

"A cheaper way to put the fluid in is to use the nozzle/cap that comes on most gear oil bottles."

That works so well for me that I try to use one cap for all bottles of oil and save a few 'good' caps (like on Mobil 1 gear oil bottles) for use on bottles that have 'crummy' caps. Another suggestion is to make sure that the foil cap on the bottles is intact before you leave the store.

 

[IslaVistaMan]

Martyi, you don't say what your new Ridgeline takes, but if you're going to go to the trouble of doing this (and believe me, it will be worth it), use as high a performance synthetic diff fluid as you can get.

One thing I can tell you for sure: If Honda uses a magnetic drain plug, you'll be amazed at how much metal there is on it!

 

[martyi]

All great tips guys - thanks!

 

[ex_MGB]

The VTM-4 rear has electronically controlled clutches to distribute torque as necessary. I would do some research on type of fluid to use and have a rock solid reason not to use the correct Honda fluid. Actually, I'd just use Honda fluid and change maybe 1/3 more often than the manual recommends.

Hondas have a reputation, whether deserved or not, of having a marked preference for Honda fluids for everything except engine oil (though I use that as well in my '05 Ody).

 

[johnd]

Another trick for installing gear oil is to heat the container in the microwave oven until it gets thinner and will flow better. Be sure the foil cap is removed.

 

[porcupine73]

Just don't let the wife see you use the kitchen microwave for shop purposes. It's akin to taking the vacuum cleaner outside.

 

[AcuraTech]

VTM-4 system on this truck does NOT use standard gear oil. It uses VTM fluid which looks like trans fluid with a slight purplish tint. It is also about the same consistency of trans fluid. I can almost guarantee that if you change it with the recommended fluid at the recommended interval you will not have a problem. Towing, etc, doesnt matter - it still needs to be changed to get rid of clutch material and condensation and to replace worn out additives.