Oil - going from 0w20 to 0w40

[ShadowsPapa]

The manufacturer, ZF, states that the fluid and filter should be changed, depending on use between 50-75K miles.

Here is a video showing multiple ZF sources stating that the fluid IS NOT a lifetime fluid…

And yet I have shown the opposite in their documents. Go find my other posts.
There is more than just one ZF fluid. Maybe they are showing the other, cherry picking to fit their agenda. Lot of that on YouTube

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[ShadowsPapa]

 

[Hootbro]

Back in 2016, ZF recommended 80K to 120K KM (50K to 75K MI) change intervals on their 8 Speed Oil Change Kit documentation. By 2022 and with their latest 2024 dated PDF for the 8 Speed Oil Change Kit, mileage recommendations were removed.

That basically leaves their latest TE-ML 11 document dated 2026 now recommending a 150K KM (93K MI) change interval for the ZF 8 Speeds as @ShadowsPapa mentioned. This document is the first I have seen ZF use the term "Lifetime Fill".

Anybody recommending 80K to 120K KM (50K to 75K MI) change intervals is only incorrect in that it is outdated recommendations now having been superseded by 150K KM (93K MI) change intervals by ZF.

 

[Jrgunn5150]

Back in 2016, my Ram Ecodiesel was brand new.

445,000 miles and 9 years later when the block heater burned it to the ground, it still had the same transmission fluid in it.

 

[ShadowsPapa]

Back in 2016, ZF recommended 80K to 120K KM (50K to 75K MI) change intervals on their 8 Speed Oil Change Kit documentation. By 2022 and with their latest 2024 dated PDF for the 8 Speed Oil Change Kit, mileage recommendations were removed.

That basically leaves their latest TE-ML 11 document dated 2026 now recommending a 150K KM (93K MI) change interval for the ZF 8 Speeds as @ShadowsPapa mentioned. This document is the first I have seen ZF use the term "Lifetime Fill".

Anybody recommending 80K to 120K KM (50K to 75K MI) change intervals is only incorrect in that it is outdated recommendations now having been superseded by 150K KM (93K MI) change intervals by ZF.

And of course, as always - anything should be tempered with how it's used. If you tow heavy loads, in hills and heat - then reduce the interval down accordingly. Lifetime doesn't mean forever with abuse or harsh use.
This means for people like my wife - she could easily go 80-90K before any change. I tow, so I'd take that down a bit. I don't abuse it, or let it hunt gears constantly (that matters, too!!) - I'd not even think about anything less than perhaps 70K with my use. Heck, I've seen TF727s go 90,000 miles before a fluid change and even at that, it wasn't terrible. (I used to rebuild automatics in a shop I worked at - I saw all kinds from abuse to extremely mild use)

Fluids have changed a lot over the years. Technology has changed. Even transmission programming can impact needed change intervals. When they changed from downshifting one at a time, to two at a time, that helped extend the change interval - less wear. It's a complex situation that many without experience try to over-simplify (or worse, go by youtube or forum posts from people who really don't know)

 

[Rusty PW]

You guys still using Dino piss for oil. I use abiogenic oil.

 

[smlobx]

If you bother to read the actual publications posted above it says…


5-, 6-, 8- and 9-speed as well as 4HP20 automatic transmissions:


ZF 5-, 6-, 8- and 9-speed as well as the ZF 4HP20 automatic transmissions are filled maintenance-free with specially developed semi-synthetic ATF oils. However, due to the many factors influencing the service life of transmissions in individual operation, ZF recommends an oil change after 150,000 km for its transmissions. In operating conditions with high temperatures and loads, or with unknown vehicle use in the past, it can make sense to change the transmission oil at shorter intervals.

—-

please read the last two sentences…

 

[ShadowsPapa]

If you bother to read the actual publications posted above it says…


5-, 6-, 8- and 9-speed as well as 4HP20 automatic transmissions:


ZF 5-, 6-, 8- and 9-speed as well as the ZF 4HP20 automatic transmissions are filled maintenance-free with specially developed semi-synthetic ATF oils. However, due to the many factors influencing the service life of transmissions in individual operation, ZF recommends an oil change after 150,000 km for its transmissions. In operating conditions with high temperatures and loads, or with unknown vehicle use in the past, it can make sense to change the transmission oil at shorter intervals.

—-

please read the last two sentences…

We all did. That is exactly what I said in response to Hootbro if you read my response. Our point was that it does say lifetime, and it doesn't give the specific numbers otherwise mentioned - those are OLD and do not apply. So it's you missing the point.

Go read our posts again.
50K-75K is old, outdated information. It does use the term lifetime and does state shorter may be needed. Nope, we didn't miss anything.
Go read my other posts over the years.

 

[g2020]

We talked about service intervals for the automatic transmission back in September.

From a different post:

• See doc #2 (sixth paragraph) for the service interval of 150,000 km (93,000 mi) for normal driving
• See doc #2 (sixth paragraph) for the shorter service interval, unspecified, for severe duty
  • For a list of recommendations/opinions, see service intervals for the automatic transmission
• See doc #3 (sixth paragraph) for the same service interval info provided in doc #2

Each of the docs on the list above is the latest from ZF. Each link to the ZF website is also provided.

It is reasonable to believe that 1) the ZF licensing agreement has a reporting requirement, and 2) ZF has access to relevant licensee service records. As @Hootbro has shown us, ZF occasionally publishes updated guidance. If ZF didn't do this, "life of the vehicle", from the owner's manual, would be our only service interval guidance for the automatic transmission.

As for "lifetime oil", I believe that ZF included this language in each PDS to enable some of their licensees to meet CAFE requirements. However, in my opinion, it doesn't make sense because the specific service interval of 150,000 km (93,000 mi), for normal driving, is shown in the next sentence in the same paragraph.

Content from the Jeep owner's manual is also provided in the same post, but it is not helpful for service intervals.

For a Gladiator, what many might consider normal driving can be classified as severe duty. Frequently driving faster than 70 mph, in temperatures above 90°F, and in stop-and-go traffic are each considered severe duty.

Also see "What is Severe Duty?" at the beginning of Fluid and Filter Lineup.

 

[DanW]

I am sure people will say i am wasting my money, or that i am ruining my vehicle. But, my 2018 JLUR went 156k miles without any engine issues (aside from the filter housing).

My 2023 Gladiator Mojave is at 40k trouble free miles too..

I run 5w30 full synthetic and change it every 3k miles. I add in zddp zinc each change.

My drivetrain is quiet, not rattles, no chatter, and the motor runs smooth and clean.

Oil changes cost me about 30.00 every 3k miles, but in these "questionable" engines, i do feel like this makes a difference.

time will tell if this is as reliable as the 18.

Edit: I know that a lot of people on here have posted the generational changes from the early non vvt and non vvl (or combined) engines. But the 3.6 in the current generation is used in other global markets and calls for 5w20 or 5w30 depending on region. The Axles also call for 90w140 from Dana's site and the ZF lifetime transmission fluid according to ZF is for 60k miles.. Which to me at least means it's highly likely CAFE is who is dictating the oil numbers, if not you would think they would be identical globally.

The current 3.6 DOES NOT call for anything other than 0w20 in other markets. Not even in the Middle East.

 

[Hootbro]

The current 3.6 DOES NOT call for anything other than 0w20 in other markets. Not even in the Middle East.

This is true.

 

[g2020]

The current 3.6

Your finding about grades being no different outside of the U.S. means The Motor Oil Geek will need to change part of his video (starting at 0:54).

I still think that Jeep meant what they said when they added viscosity grades to the revised 2020 owner's manual. 0W-20 is recommended and four other grades are listed. However, there are some differences between the advice in the revised 2020 owner's manual and the 2026 manual. I plan to contact Jeep about the differences.

- Quiet changes: In my opinion, the changes are a result of loosening CAFE standards
- Inconsistent viscosity grades: While there are three grades in common, advice on viscosity grades for the 3.6L engine in the Jeep Gladiator is different for the two examples discussed in this post

Assumption: A viscosity grade listed in the owner's manual may be used; see fact #3 in key facts about motor oil compliance and viscosity grades. I think that this is a safe assumption, but this will not be settled until I contact Jeep.

The advice on 1) page 251 of the revised 2020 owner's manual and 2) page 238 of the 2026 owner's manual (below) are written differently. In the revised 2020 manual, there are no conditions mentioned for the other grades listed. However, in the 2026 manual, the grades are grouped by API trademark type and the reader is redirected to page 283.

Viscosity grades listed in revised 2020 owner's manual:
- 0W-20, 5W-20, 0W-30, 5W-30, and 10W-30
- Unlike the 2026 owner's manual, this advice ends here (no continuations)

>>> Grades in common: 0W-20, 0W-30, and 5W-30 (in both revised 2020 owner's manual and 2026 manual)

Viscosity grades listed in 2026 owner's manual:
- API Starburst trademark: 0W-20, 0W-30, and 5W-30 (5W-20 and 10W-30 are not listed in 2026 owner's manual)
- API Donut trademark: 0W-40 and 5W-40 (0W-40 and 5W-40 are not listed in revised 2020 owner's manual)

2026 owner's manual, page 238:

2026 owner's manual, page 283:

 

[Pismo61]

Looks like its ok to use the other oils mentioned 5w30,0w30 and so on,correct.

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