Gear Oil at 20,000 miles in Ford 9.75” Diff

[Panda87]

If there is anything I've learned from my trips to HPL, including the open-house event two years ago, it's that you should NOT mix brands/grades of boutique lubricants.

It is generally very safe to mix most store-bought API licensed fluids for any particular application, mainly because most API licensed fluids don't really stretch the envelope when it comes to additives, etc. It's not like a little more or less of Ca or Mg, etc, is going to upset the apple cart ...

But boutique lubes like Amsoil, RP, RL, and especially HPL are tailored to specific goals and often have very unique chemistry. For example, the anti-foam package in HPL lubes is sensitive to the % ratio of concentration. Further, the lubes may or may not have additives which compete for solubility, etc. Then there's the esters, ANs, etc ... Even ZDDP can be an issue if too much is present. This is like the whole "Goldilocks" topic; too much or too little of a good thing is a bad thing. When you mix products without knowing the EXACT additive package in both, and how they will interact with each other, you have no idea of what effects you may be creating.

Amsoil makes great products. HPL makes great products. But without knowing the potential for chemical coercions pro and con, I'd advise to stay away from mixing them.

What you can do, and what you should do, are two different things.

I wasn’t very clear from my first post unfortunately. I explained it a few posts in, but sometimes that gets lost in the fray.

The oil I pulled was purely Ams SG 75w-140.

The oil that went in was all Ams SG of various grades (3.5 pints) because I wanted a carrier oil for the HPL Diff Life Cleaner (the only non-Ams oil added at .9 pints)
Do you think the small amount of the HPL diff life cleaner would affect the fluid that adversely? Before I jumped into this little experiment, I noted that the page for diff life cleaner specifically stated “Compatible with other conventional and synthetic gear oils” so I assumed it was suitable to mix with the Amsoil SG I had remaining, but I’m no tribologist or expert.

 

[dnewton3]

My apologies; I misunderstood your intent. Though my advice would be salient for anyone considering mixing fully formulated lubes.

The HPL diff cleaner is generally only intended as a "cleaner". While it's very specific and well suited to the task, it does not present compatibility issues I mentioned previously. Using it with another fluid will be fine as long as you run it and then dump it after a short-to-moderate OCI.

 

[Panda87]

My apologies; I misunderstood your intent. Though my advice would be salient for anyone considering mixing fully formulated lubes.

The HPL diff cleaner is generally only intended as a "cleaner". While it's very specific and well suited to the task, it does not present compatibility issues I mentioned previously. Using it with another fluid will be fine as long as you run it and then dump it after a short-to-moderate OCI.

All good sir! Like I said, my initial post’s explanation was very poor, so that’s all on me.
My plan was to run the cleaner for 5k then drain and fill with a single source 75w-140.

Thanks for your input! I appreciate your knowledge and time

 

[D1dad]

I originally leased my 18 rogue and the lease ended during COVID, which I decided to buy it. So @40k I changed the front and rear and holy heck was it as nasty as anything I’ve ever smelled. Grey, nasty and looked like it had 400k on it. I used amsoil for a couple changes (10k) each, then motul 80w90 and have some schaeffers ready for the spring. Thus far motul has yielded the best mpg as well as sound and smoothness.

 

[Panda87]

I originally leased my 18 rogue and the lease ended during COVID, which I decided to buy it. So @40k I changed the front and rear and holy heck was it as nasty as anything I’ve ever smelled. Grey, nasty and looked like it had 400k on it. I used amsoil for a couple changes (10k) each, then motul 80w90 and have some schaeffers ready for the spring. Thus far motul has yielded the best mpg as well as sound and smoothness.

How did each successive change look? Any improvements in nastiness or color?

 

[D1dad]

How did each successive change look? Any improvements in nastiness or color?

I forgot to add this part. I did a short run (a few k) just like you did with some carquest 80w90 I had laying around. That short run cleaned it up and it’s been spotless ever since. Minus what the motul looks like when it comes out, since that stuff is grey to begin with. The transfer and the rear diff only hold a quart together, so it’s cheap. Unlike yours would be. I'm at almost 100k and change it out every spring given the volume.

 

[Panda87]

I forgot to add this part. I did a short run (a few k) just like you did with some carquest 80w90 I had laying around. That short run cleaned it up and it’s been spotless ever since. Minus what the motul looks like when it comes out, since that stuff is grey to begin with. The transfer and the rear diff only hold a quart together, so it’s cheap. Unlike yours would be. I'm at almost 100k and change it out every spring given the volume.

That’s awesome to hear! Hoping the same happens with mine. Thanks for the info about your experience!

 

[userfriendly]

Delete

 

[jetman]

@Panda87
here's a thread I did w/used gear oil analysis report, Amsoil SVG 75w90, 41,000+ Lb vehicle, 43k miles and 9 yrs.
https://bobistheoilguy.com/forums/t...d-my-sample-for-analysis.360658/#post-6292802

 

[Rob_Roy]

Update for everyone! My little science experiment of letting the mason jar of gear oil sit in my office has borne fruit! It would appear the Amsoil SG had cleaned the differential and held the particulates in suspension. After a great length of time, those particulates have settled to the bottom of the jar as a very dark gray slurry while the gear oil itself has changed to a dark honey color as the particulates settled to the bottom.

Looks like the Amsoil SG did exactly what it was supposed to! @Pablo this one points to the SG base oils as fantastic for cleaning up a diff/gear sets.

View attachment 261178

Great feedback. It will be interesting to see how the oil looks after your "flush".

 

[Panda87]

Now that I got all the Ford guys in one room, instead of starting a new topic, I’ll just ask a simple question on fluids.
My son drives a crackenwagen in northern BC. Yesterday he bought a 2012 F350 crew cab long box with the 6.2L gasoline engine with 140,000 miles for $9,000 or $6,300 USD.
When he swings south this spring I’ll do all of his fluids. Engine, atf, diffs, transfer case and power steering.
This is our first Ford truck in the family and just goes to show ya, never say never.
In 2016 Ford went from 5w20 to 5w30 in that engine. I have 14L of 5w30 Dexos 1 gen 3 in my stash plus six jugs of M1 FS Euro 0w40 he can have. I also have 5w30, 10w30, 10w30 FA-4 and 5w40 HDEOs in my 300L engine oil stash.
I have a pail of 80w140 Delo, a pail of Chevron HD synthetic ATF and a pail of Chevron synthetic multi vehicle low vis ATF, all unopened.
What say you Ford guys?

You put a lot of questions and fluids in a single post. Might get better luck structuring your post better. Typically, it’s considered good forum etiquette to start your own post when it’s not something to do with the OP. However, from what I can gather:
I’m not going to bother to look up the specs for your 6.2, which I may or may not remember correctly is a member of the Ford Modular V8 family. 5w-30 will likely work fine. As will the 0w-40 (which I would reserve for warmer weather and towing if this vehicle will be used for it.
The 6R80 (I’m assuming that’s what you’ve got because you didn’t mention a transmission) uses a low viscosity ATF. It’s not picky as to what brand. I’m running Amsoil low-viscosity ATF (blue cap) in mine without issue. It’s a much smoother transmission than the 7g-Tronic in my MB GL450.

Again, you’d be better served by making this it’s own post.

 

[Panda87]

@Panda87
here's a thread I did w/used gear oil analysis report, Amsoil SVG 75w90, 41,000+ Lb vehicle, 43k miles and 9 yrs.
https://bobistheoilguy.com/forums/t...d-my-sample-for-analysis.360658/#post-6292802

That’s a sweet looking motorhome you’ve got! We tow a 33ft 7500lb loaded camper with our Navigator. We love our little home on wheels and use it often. Does your differential really take 4.5 gallons!? I knew they were big, but holy moley, that number surprised me.

 

[jetman]

Does your differential really take 4.5 gallons!? I knew they were big, but holy moley, that number surprised me.

Yes, 4.5 gals.
It weighs 41K Lbs,
plus, we are always towing something,
like our 4.5k Lb Toy FJ Cruiser,
or
a 10k # enclosed car trailer.

I wouldn't hesitate to run SVG 75w90 in your diff.
I run it in everything that's spec'd for gear oil.

 

[Langanobob]

I've never used a diff cleaner and I’ve got to say I don’t see the need. There are no combustion byproducts/sudge in a differential, at least I have never seen any. Maybe some dark fluid that may leave an inconsequential film when drained. Can someone enlighten me? Thanks!.

 

[Panda87]

I've never used a diff cleaner and I’ve got to say I don’t see the need. There are no combustion byproducts/sudge in a differential, at least I have never seen any. Maybe some dark fluid that may leave an inconsequential film when drained. Can someone enlighten me? Thanks!.

If the diff was like mine and had 150k worth of service on the factory fill, the stuff in the diff that comes out is gnarly. Look through my post to see what the second drain of quality Amsoil gear oil looked like. That’s the second drain after removing the factory fill and it looked like that. If axle seals are bad, breather tubes are in disrepair, leaking diff cover, etc can all add to the issue as well.

 

[Panda87]

Yes, 4.5 gals.
It weighs 41K Lbs,
plus, we are always towing something,
like our 4.5k Lb Toy FJ Cruiser,
or
a 10k # enclosed car trailer.

I wouldn't hesitate to run SVG 75w90 in your diff.
I run it in everything that's spec'd for gear oil.

For the sake of some math fun, I ran some numbers.
My GCWR of my tow rig is 14,600lbs by scale weight. That’s 35.6% of the weight of your motorhome (not including your towed implements of course).
My differential capacity is 2.2 quarts versus yours at 18 quarts. That’s 12.2% of your total capacity.

Makes me wonder what the difference (if any) of heat buildup, more/less fluid capacity, etc have on the choice of lubricant viscosity grade in these two applications? Nothing more than some curiosity for us to chew on, lol.