Early fluid changes: differentials, transfer case, manual transmission

[Viper501]

I’m not going to get into the middle of which fluid to use. However, there are a couple non-mechanical factors that you have to consider when taking the OEM (ANY OEM not just Jeep) advice on service and maintenance.

First is the aforementioned CAFE requirements that force Jeep and every other manufacturer to try to eke out every last bit of fuel economy so the 900 pound gorilla (named Epa) doesn’t lose it and fine them. This process goes from the lighter weight materials, thinner glass, etc., on down through the rest of the process.

Second, the OEM only has to worry about the truck for the life of the warranty period. In most cases that is really very short term in terms of modern vehicles. Even with more expensive brands (marginally given JT prices and options) such as BMW and Mercedes with longer base warranty periods, the warranty expires well before the average consumer is going to reach a wear level that will cause failure. Therefore, they have no financial incentive to require more frequent, or more thorough, service schedules. The dealers may make more money but Jeep, et al., won’t.

That is important because the consumer side of things dings the manufacturers based on the the costs of ownership. JD Power, Consumer Reports, and others have made that a holy grail for the manufacturers. When an average consumer looks at the costs of ownership including oil changes every 5k miles, transmission services, etc., the costs of ownership based on maintenance increases. Manufacturers who put in a 10k mile oil change, or a flex service schedule, can claim reduced maintenance expenses and compete ‘better’ against rivals. (This is really a proverbial race to the bottom for them.)

This is a huge issue in the luxury branded cars such as BMW and Mercedes. Both claim ‘lifetime’ transmission fills. No need to ever flush your auto transmission or change the fluid. It will last forever. Nope. It will last as long as the transmission lasts. Since that will ordinarily exceed the warranty, and even an extended warranty, no need for them to worry about it.

With all of these manufacturers starting to provide ‘free’ or ‘included’ maintenance packages as well they are further incentivized to make things work for their wallet not the benefit of the mechanicals of the vehicle (or the long-term consumer’s wallet).

That is a long-winded way of saying that Jeep, and all other OEM’s, are fairly FOS when it comes to maintenance and have significantly different goals from the consumer who intends to keep their vehicle beyond the factory warranty period / mileage.

Kudos to those of us who recognize that fluid changes are a significant way of improving the longevity of our vehicles.

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[Jaybre007]

Not sure if you have lockers or not but if the drain plug had that mound of magnetic sludge on it, your locker sensor magnet will too and when that’s all coated up with magnetic debris, your locker engagement and disengagement won’t work like it should.
If you like having lockers that work or you want them to work if you ever need them, pop off the diff covers, unplug the locker sensor and pull out the small torx screw holding it in and gently pull it off the magnet and out.

You’ll see that magnet will be full of metal paste coating it and that needs to be clean. The cover gasket is reusable and your only out 1.5 quarts or so but it’s chump change and now it’s all clean and you’ve had some ‘hands on’ in getting it all cleaned up proper.

With the sensor out, spray around in there with brake cleaner and wash all the metal filings and bits out. Dry it out and install it all back again. Super simple and easy and you’ll even enjoy doing it.

Awesome pics, thanks for posting these!

 

[Jaybre007]

I’m not going to get into the middle of which fluid to use. However, there are a couple non-mechanical factors that you have to consider when taking the OEM (ANY OEM not just Jeep) advice on service and maintenance.

First is the aforementioned CAFE requirements that force Jeep and every other manufacturer to try to eke out every last bit of fuel economy so the 900 pound gorilla (named Epa) doesn’t lose it and fine them. This process goes from the lighter weight materials, thinner glass, etc., on down through the rest of the process.

Second, the OEM only has to worry about the truck for the life of the warranty period. In most cases that is really very short term in terms of modern vehicles. Even with more expensive brands (marginally given JT prices and options) such as BMW and Mercedes with longer base warranty periods, the warranty expires well before the average consumer is going to reach a wear level that will cause failure. Therefore, they have no financial incentive to require more frequent, or more thorough, service schedules. The dealers may make more money but Jeep, et al., won’t.

That is important because the consumer side of things dings the manufacturers based on the the costs of ownership. JD Power, Consumer Reports, and others have made that a holy grail for the manufacturers. When an average consumer looks at the costs of ownership including oil changes every 5k miles, transmission services, etc., the costs of ownership based on maintenance increases. Manufacturers who put in a 10k mile oil change, or a flex service schedule, can claim reduced maintenance expenses and compete ‘better’ against rivals. (This is really a proverbial race to the bottom for them.)

This is a huge issue in the luxury branded cars such as BMW and Mercedes. Both claim ‘lifetime’ transmission fills. No need to ever flush your auto transmission or change the fluid. It will last forever. Nope. It will last as long as the transmission lasts. Since that will ordinarily exceed the warranty, and even an extended warranty, no need for them to worry about it.

With all of these manufacturers starting to provide ‘free’ or ‘included’ maintenance packages as well they are further incentivized to make things work for their wallet not the benefit of the mechanicals of the vehicle (or the long-term consumer’s wallet).

That is a long-winded way of saying that Jeep, and all other OEM’s, are fairly FOS when it comes to maintenance and have significantly different goals from the consumer who intends to keep their vehicle beyond the factory warranty period / mileage.

Kudos to those of us who recognize that fluid changes are a significant way of improving the longevity of our vehicles.

Well said. I heard many lease people never even do maintenance because it did not come with the vehicle. Crazy sounding but I wondered why the dealership is always saying to do maintenance at a different interval than the manual and what you said makes perfect sense. I strongly believe you can always do more service intervals than the minimum required from the manufacturer because only you the driver/owner knows what the vehicle goes through and in the end if your planning on long term ownership then do what makes you feel comfortable in the end it is your wallet but also piece of mind. Preventive maintenance is key to less expensive maintenance!

 

[Viper501]

Well said. I heard many lease people never even do maintenance because it did not come with the vehicle. .... if your planning on long term ownership then do what makes you feel comfortable in the end it is your wallet but also piece of mind. Preventive maintenance is key to less expensive maintenance!

A lot of lease owners look at it as like driving a rental. Not their car and they don't care. As a result, and the effect that has on the manufacturers through the leasing residuals, several are now "including" maintenance of some sort OR offering a pre-paid maintenance package as a part of the lease. The pre-paid maintenance then gets factored into the lease and for a lot of folks leasing as a write-off makes the maintenance part of the write off.

 

[ShadowsPapa]

A lot of lease owners look at it as like driving a rental. Not their car and they don't care. As a result, and the effect that has on the manufacturers through the leasing residuals, several are now "including" maintenance of some sort OR offering a pre-paid maintenance package as a part of the lease. The pre-paid maintenance then gets factored into the lease and for a lot of folks leasing as a write-off makes the maintenance part of the write off.

Like the guy here in Iowa who told the trooper "it's a lease car, I don't need to do that" (regarding oil changes)

For transmissions, one need only look at what the maker/designer/inventor of the transmission says in our case and that doesn't match what the book says.
Can you go 100,000 miles? Yeah, sure, and longer (the transmission in my father's WJ went 127,000 miles and was never touched for anything and for all I know it's still going to this day - wise? Silly question)

Observing some of the posts out there in the world related to the differentials under our Jeeps in the past few years - and the double-ball bearing pinion bearings, I'm not going over the top with really short intervals but won't go as far as I usually do with my vehicles. The days of tough, heavy bearings handling crazy loads are over. So as I go along, i temper and revise plans. Nothing is set in stone.

 

[bd100]

Minor update: Te pinion seal is leaking slowly, the noise is getting worse, and it's scheduled for a dealership visit soon. Someone said they tend to change the entire axle instead of going into the diff, in which case I'll have to uninstall the skids for the shocks and control arms. At least then I can paint them, as I should have from the start. Most aftermarket vendors' power coat doesn't seem to be all that good. And after break in I'll put in some 75W140.

 

[ShadowsPapa]

Minor update: Te pinion seal is leaking slowly, the noise is getting worse, and it's scheduled for a dealership visit soon. Someone said they tend to change the entire axle instead of going into the diff, in which case I'll have to uninstall the skids for the shocks and control arms. At least then I can paint them, as I should have from the start. Most aftermarket vendors' power coat doesn't seem to be all that good. And after break in I'll put in some 75W140.

Here's hoping they get that taken care of soon as a pinion bearing that goes can lock the whole danged thing. I know - I rebuilt one a while back that blew the pinion bearings shortly after a shop in Kenosha rebuilt it for a friend. Stopped that car pretty fast.
I can't predict what they'll do for a pinion bearing but I do hope they do the whole shootin' match for you.

And I hope no aftermarket people are proud of their powder finishes - their pride would be grossly misplaced. I'd think they'd do a good job on the finish to hide defects and make their products look better than they might be but they just haven't figured that out.

 

[JTGuy]

My Diffs get Torco RGL 85-140 non synthetic. Rated GL-6. That stuff is awesome.

 

[bd100]

Dealer now waiting for parts for a differential rebuild.

 

[ChrisNLA]

Like the guy here in Iowa who told the trooper "it's a lease car, I don't need to do that" (regarding oil changes)

For transmissions, one need only look at what the maker/designer/inventor of the transmission says in our case and that doesn't match what the book says.
Can you go 100,000 miles? Yeah, sure, and longer (the transmission in my father's WJ went 127,000 miles and was never touched for anything and for all I know it's still going to this day - wise? Silly question)

Observing some of the posts out there in the world related to the differentials under our Jeeps in the past few years - and the double-ball bearing pinion bearings, I'm not going over the top with really short intervals but won't go as far as I usually do with my vehicles. The days of tough, heavy bearings handling crazy loads are over. So as I go along, i temper and revise plans. Nothing is set in stone.

My mothers 2006 Chevy Equinox has 246,000 miles -

- on the original transmission fluid and coolant ? Coolant will be changed soon as I believe the thermostat needs replacing.

Transmission though? At this point it's a circus act and we're gonna see how long it lasts. It shifts really well still, LOL.

As for the OP - sounds like the findings I had in my JK. I did the diffs on it at around 35K miles when I swapped in Poison Spyder diff covers. I'll probably do all the fluids on my Gladiator at the intervals offered in the manual, save for engine oil which I do every 5-6K, not via OLM.

 

[MrClortho]

Yes, I should have mentioned that the back differential has a limited slip. So that's part of the darkness of the fluid.

We'll see if the back diff holds up. There is a quiet metallic swishing noise occurring back there somewhere, road speed dependent. But it doesn't (yet) depend on acceleration / coast / deceleration. Nor does it change with a hard left or right turn. Nor it I loosen the parking brake. And I raised each of the 4 tires one at a time to shake them, no looseness. And I took off the back wheels to check the rotors, no rocks or twigs stuck in there. So I don't yet know what that is.

I appreciate your write up and I am one that changes all those fluids at 25k myself. If you have the factory limited slip, it will probably come apart and sooner than expected. The shavings you are getting are unfortunately somewhat normal for the rear diff with the factory LS. My good friend owns a Jeep shop and often finds metal from the LS teeth in the rear diff, including my two JK's at only 30k miles. I put a Yukon LS in both of them back then which was a noticeable improvement. The interesting part is these chunks of metal don't cause failure of the diff often that we have seen but....lol. I wish I still had a picture of the broken teeth on mine, and I was only running 32's at the time.

On my JT, I have only a little more than 10k miles but plan on doing something different at 25k, but not hearing favorable feedback from Yukon products lately. In fact, when I installed the 5.13s, my buddy steered me away from Yukon and to Revolution Gear. He warranties the products and installs and has migrated that direction. As a side note, he also exclusively uses Royal Purple gear grease and again, warranties the work, so that leads me to believe he has good luck with it. I brought him the Mopar grease once with that LS additive and instead of using it, he used Royal Purple and did not charge me for it because he believes in it. I don't want to derail the thread on grease types because seems like everyone has strong opinions on what is best.

On your next fluid change, inspect the teeth on the LS unit carefully.

 

[jav_eee]

Awesome pics, thanks for posting these!

if you're doing all this you might as well add one more step and pot the sensor to make sure it keeps working like it should.

 

[ShadowsPapa]

I appreciate your write up and I am one that changes all those fluids at 25k myself. If you have the factory limited slip, it will probably come apart and sooner than expected. The shavings you are getting are unfortunately somewhat normal for the rear diff with the factory LS. My good friend owns a Jeep shop and often finds metal from the LS teeth in the rear diff, including my two JK's at only 30k miles. I put a Yukon LS in both of them back then which was a noticeable improvement. The interesting part is these chunks of metal don't cause failure of the diff often that we have seen but....lol. I wish I still had a picture of the broken teeth on mine, and I was only running 32's at the time.

On my JT, I have only a little more than 10k miles but plan on doing something different at 25k, but not hearing favorable feedback from Yukon products lately. In fact, when I installed the 5.13s, my buddy steered me away from Yukon and to Revolution Gear. He warranties the products and installs and has migrated that direction. As a side note, he also exclusively uses Royal Purple gear grease and again, warranties the work, so that leads me to believe he has good luck with it. I brought him the Mopar grease once with that LS additive and instead of using it, he used Royal Purple and did not charge me for it because he believes in it. I don't want to derail the thread on grease types because seems like everyone has strong opinions on what is best.

On your next fluid change, inspect the teeth on the LS unit carefully.

Limited slip teeth? Shavings?
Have you rebuilt some of these?
There's nothing in the limited slip to generate shavings of teeth, or shavings at all.
It's a clutch disk alternating with steel disk setup.
These don't go any more often than any other limited slip (which is seldom) if they are actually kept maintained with proper additive.
The only thing that could make shavings are not the limited slip disks or clutches, it would be like any other in that respect.
The factory limited slip doesn't come apart sooner than any other factory limited slip unless abused, misused or not maintained with a good quality additive.

I had a locked up differential assembly brought to me that came from a "well respected axle shop a buddy runs" in Kenosha. Yeah, Jeep and AMC and so on. "the guy knows what he's doing" I was told.
I took the carrier apart and found blue steel plates, incorrect sequence of assembly and the spring plates in the wrong place. And that was from a shop that does "many Jeep" axles.

Frankly, it's an area where I trust myself and only a tiny handful of others.

Anyway, on limited slip - there's nothing to generate shavings. There aren't any "limited slip gears". They don't exist on these.

On your next fluid change, inspect the teeth on the LS unit carefully.

What teeth? You mean the side or carrier gears?
Or the spider gears?
All differentials have those and they are the same in all - limited slip or not.
(except many designs of limited slip have 4 spiders instead of 2 for more even pressure on the side gears during uneven torque events)
If you mean inspect the clutch pack, you can't without disassembly.
Those are sandwiched between the side gears and carrier case.

If you broke teeth on the side or carrier gears, it could happen on any differential.

Here's a smaller version of the clutch type limited slip - curious as to which gears/teeth you were talking about.
This one had a ton of miles on it and the respected shop that rebuilt it didn't know their head from........ as far as clutch disk assembly, pinion preload, depth and so on.

 

[JTGuy]

At 10K miles I have done the diffs and TC. Found nothing so I should be good for a while. Not going to touch the trans. BTW, the TC takes 2 Qts.

 

[MrClortho]

The smaller teeth in this picture or something similar. I assumed they were part of the factory limited slip, but I have not personally rebuilt one, so perhaps I am mistaken. I have seen 4 instances where they were broken off in a little more than a year and two myself with less than 35k miles. I also had it happen in a Jeep Liberty years back. All my rigs had the factory limited slip, so I made the assumption.

When I replaced them, it was with this type of unit from Yukon.

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