Your opinions on differential service.

[MichaelRS]

So, as stated in my other threads, I have this 99 Honda Passport, or rather my Ex has it, with 195 on it so I plan on servicing the differential. What I'm wondering is if I should just do a drain and refill (apparently there's no drain plug. You have to suck it out with a tube through the fill hole) or should I go to the much bigger bother, and for me expanse, of dropping the cover and doing it that way.

Now, under the heading of a little knowledge is a dangerous thing, I'm of two minds on this....

First is the most simple and expedient way to do it is through the fill hole, especially since it doesn't look like there's any leakage from the housing.

On the other side of the coin, in a number of the YouTube videos I have just watched regarding differential servicing, when guys did the cover removal version, obviously fluid would drain out, but inside the cover and on the gears themselves was left a BUNCH of gunk.
In some cases they wiped out millimeters thick gunk from inside the cover, with all kinds of crap stuck to the magnets, and then sprayed down the gears with whatever solvent to get the rest of it out before putting it back together and refilling.

So I'm wondering if I just suck out the old fluid and put in the new will that loosen any gunk to the point that it would somehow break free and intermixed with the new oil and somehow get in there and mess up the gears.
I don't fully understand the dynamics there so that's the best way I can express it. But I think y'all get my point.

Or is that not really likely to happen with a simple drain (suck out) and refill despite the differential's age?

I would like to avoid removing the cover, if that's practical, because in order to do that I'm going to have to take it to somebody and I would like to not spend the money, but only if the other way is reasonable.

 

[2strokeNorthstar]

The wrong way is better than nothing but not ideal.

 

[ctechbob]

D&F is better than nothing at all. I wouldn't worry anything that's left in there, its not going to get any worse than it already is.

 

[slacktide_bitog]

Which diff do you have? Several were available for your 99 Passport

It could be one of any of these:
GM 10-bolt 7.625
GM 10-bolt 8.625
Dana/Spicer 44-3 10-bolt 8.5

Aftermarket covers are available that have a drain plug.

If you can remove the fill plug yourself, you can do the rest of the job too

Out of these, which one is your cover shaped like?

 

[MichaelRS]

Which diff do you have? Several were available for your 99 Passport

It could be one of any of these:
GM 10-bolt 7.625
GM 10-bolt 8.625
Dana/Spicer 44-3 10-bolt 8.5

Aftermarket covers are available that have a drain plug.

If you can remove the fill plug yourself, you can do the rest of the job too

Out of these, which one is your cover shaped like?

Yes, thanks, I do have the normal dexterity of the average person to be able to do it myself, but as an apartment dweller I just don't have a good area to work that extensively in.

But that aside, I just took a quick look at it earlier today, when the idea came to me, and did not bother to note its particular shape...not realizing I had any real need to know that as I just figured it would be THE standard differential that came on those cars.
So thanks for the heads up regarding that

Guess I'll have to look harder at it tomorrow to see if I can figure out which one it is. Other than that, is there a way to tell who the VIN number or something?

 

[MichaelRS]

D&F is better than nothing at all. I wouldn't worry anything that's left in there, its not going to get any worse than it already is.

Well yeah, that's my thought; Better than nothing.
I just wanted it (the lubrication and hopefully thereby the function and life of it) to be improved without doing inadvertent harm from reasons I mentioned in my OP.

 

[atikovi]

I do have the normal dexterity of the average person to be able to do it myself, but as an apartment dweller I just don't have a good area to work that extensively in.

Well, you have to either jack it up or drive it up on ramps for either service. The work area is the same. Regardless, unless it's leaking, the rest of the truck will fall apart before the rear end does, so why do you find it necessary to do this now?

 

[Kira]

From what you describe, enforcement of "No Working on Cars" rules would be the big wet blanket.
At 150K, Sis' '99 Jeep Cherokee had considerable grit and crumbs lying in the rear diff's lowest regions. I'm glad I got it all clean.
Videos of diffs with clear plastic covers show the fluid whirling around fast. Some of the grit will be propelled about the diff causing wear.

Have you given any thought to which replacement fluid you'd use?

 

[ls1mike]

Don't nuke this out. Suck what you can out and refill unless it leaking. You are not making enough power to break that thing.
It is probably dirty but fine.

 

[andreigbs]

If it's for your Ex, why really bother at all? There are plenty of shops that perform this service; why would you risk getting dirty with smelly gear oil for someone who doesn't think you're worth hanging around for?

I realize that wasn't your question, I'm just wondering.

 

[wpod]

Ex? Let the new stud do the oil change.

 

[slacktide_bitog]

Yes, thanks, I do have the normal dexterity of the average person to be able to do it myself, but as an apartment dweller I just don't have a good area to work that extensively in.

But that aside, I just took a quick look at it earlier today, when the idea came to me, and did not bother to note its particular shape...not realizing I had any real need to know that as I just figured it would be THE standard differential that came on those cars.
So thanks for the heads up regarding that

Guess I'll have to look harder at it tomorrow to see if I can figure out which one it is. Other than that, is there a way to tell who the VIN number or something?

If you do look at it again and still can't figure it out, take a picture of it

 

[JeffKeryk]

If it is the 1st service I would pull the cover.

 

[MichaelRS]

Well, you have to either jack it up or drive it up on ramps for either service. The work area is the same. Regardless, unless it's leaking, the rest of the truck will fall apart before the rear end does, so why do you find it necessary to do this now?

Well, I doubt it has EVER been done. Just something I think would be a good idea to do.

 

[MichaelRS]

Have you given any thought to which replacement fluid you'd use?

Not really. Kind of looking at Lucas or Valvoline. Probably something known and common, other than "Joe's differential oil". LOL

 

[MichaelRS]

If it's for your Ex, why really bother at all? There are plenty of shops that perform this service; why would you risk getting dirty with smelly gear oil for someone who doesn't think you're worth hanging around for?

I realize that wasn't your question, I'm just wondering.

Ah, but that assumes that SHE was not the one that, for whatever reasons, decided not to hang around.
And of course we know that relationship are multifaceted.

 

[Astro14]

Not sure I would touch anything my ex owned. You do a D&F on the differential, and you’ll get blamed for the subsequent timing belt failure.

That said, I would suck it out and fill it. Been doing that on my Volvo for years.

Can’t remove the differential on that car without removing the rear suspension and dropping the subframe. 280,000 miles. No leaks. No worries.

 

[MichaelRS]

Not sure I would touch anything my ex owned. You do a D&F on the differential, and you’ll get blamed for the subsequent timing belt failure.

That said, I would suck it out and fill it. Been doing that on my Volvo for years.

Can't say you're lying on the first part there

And I totally agree with the drain and refill part if one has been servicing car regular for years.
But I really don't think the differential on this '99 Passport has ever been serviced.

But I'm guessing differentials are not as sensitive as transmissions might be to fluid changes after long periods of time, however I just don't know to what degree that applies, so that is why I'm seeking the collective wisdom here.

So, if there is going to be some benefit to having X amount of new fluid in there from a D&F, with no ill likely to come from it, that is what I'd like to do.

I know nobody here can guarantee anything, but generally speaking, as a rule of thumb, is that okay to do with a differential that old that probably has never been serviced?

So far what I'm understanding is removing the cover and cleaning the thing out would be best, but the other would be okay to do.

If I misunderstand that and there's a likely mechanical reason as to why just a D&F should not be done, such as it IS likely to create some sort of harm, then I'd like somebody to tell me.

 

[slacktide_bitog]

There is nothing wrong with doing a drain and fill on a differential that has never been serviced before

 

[andreigbs]

Ah, but that assumes that SHE was not the one that, for whatever reasons, decided not to hang around.
And of course we know that relationship are multifaceted.

Agreed, nothing about them is simple.

As for the diff itself: I've had this service done to both my diesel SUVs and both times it was a simple drain and refill with the proper spec lube.

On the GLK250 it was performed at 62k miles, on the X3d it was at 75k miles. From what I saw, both old fluids (likely original OE) were pretty dark when compared to the new stuff being pumped back in.

Also in both cases it was less than a quart of fluid. Worth doing once every 60-80k miles for the peace of mind.

On your own vehicle...