Automatic Transmission fluid change interval s on 2021 JT

[s alex]

I can't find anything in the owners manual about the transmission fluid change intervals on 2021 JT automatic transmission.
Anybody has any idea ??

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[jac04]

Jeep's position is that the transmission fluid does not need to be changed at specific intervals.

 

[s alex]

Jeep's position is that the transmission fluid does not need to be changed at specific intervals.

That means never ? Where does it say that? Happen to have a link ?

 

[jac04]

If it isn't listed in the Maintenance Schedule, then it isn't required.
https://www.mopar.com/jeep/en-us/my-vehicle/maintenance-schedule.html

 

[WXman]

Jeep's position on this is that it's a "lifetime fluid". That basically means it will last until the planned end of useful service of the vehicle, which for a domestic OE is typically 150,000 miles.

ZF, the company who designed the 850RE and makes the 8HP75, says you should change the fluid and filter at 60,000 miles.

I plan to follow the ZF advice. Fluid and filter swaps on these are a pain compared to the old days, but it's still way easier and less expensive than a new trans.

 

[Rein89]

Most manufacturers say lifetime fill so that they can lower the cost of ownership, and use that against their competitors. There are other reasons as well, but as was stated above stick to ZF's recommendation, or change it more often if you tow regularly.
Personally, I like to change fluids before what's recommended and usually on intervals I can easily remember. Oil every 5k, diffs, manual trans and transfer cases every 30k and auto trans every 50k. Fluid is cheap compared to a new gearbox.

 

[WXman]

There used to be a good video on YouTube showing how to do the fluid swap on one of these 8 speed transmissions. The guy appears to be an instructor at a vocational school. He's in an electric wheelchair, but he knows his stuff. He's working on a Chrysler sedan, but the process of changing the trans. fluid is the same as the Jeep. See if you can find that video. I lost the link. It'll give you an idea of how to tackle this job.

 

[WXman]

I found it:

 

[OVERLORD]

I found it:

Thanks for this!

 

[Mac]

I changed the fluid in my MDX, it is a ZF 9 speed, the procedure from Acura is very complicated and recommends using their software to verify temp when you check the level. I watched a few YouTube videos where people just drained it and then refilled it with the same amount, that is what I did, I don’t believe it has a cooler or a replaceable filter, the fluid was $30 a quart. The Acura maintenance minder came up with the code for transmission oil change around 50k miles, I have also changed the rear diff and transfer case fluid on it per the maintenance minder.
If the JT maintenance schedule doesn’t call for the transmission oil to be changed I probably will not do it.

 

[WXman]

I watched a few YouTube videos where people just drained it and then refilled it with the same amount, that is what I did,

The issue with that, and I think the guy in the video above mentioned this too, is that you're assuming the fluid level was correct to begin with. And we all know what they say about assuming...

You make a good point though that this isn't a routine drain and fill like it used to be 20 or 30 years ago. They've made it purposefully difficult now, so I wouldn't recommend the job to anyone who isn't somewhat mechanically proficient. It's not all that hard, but it is a little technical and there are several steps that are critical.

 

[Mac]

The issue with that, and I think the guy in the video above mentioned this too, is that you're assuming the fluid level was correct to begin with. And we all know what they say about assuming...

You make a good point though that this isn't a routine drain and fill like it used to be 20 or 30 years ago. They've made it purposefully difficult now, so I wouldn't recommend the job to anyone who isn't somewhat mechanically proficient. It's not all that hard, but it is a little technical and there are several steps that are critical.

Agreed, I did assume it was filled to the correct amount, I drained it into a container to could easily mark and refill with the new fluid to the same amount, the amount I used matched what I had read was supposed to drain out. I was taking a risk though is something went wrong I would be responsible for sure.

 

[NC_Overland]

$43/qt is super expensive, but it doesn’t surprise me because the fluid for the eight speed in my Canyon was similarly priced and it took like twelve quarts. I’m sure that our eight speeds have a similar capacity.
Long story short, I’m at 20k miles, I won’t be changing mine any time soon.

 

[ShadowsPapa]

Most manufacturers say lifetime fill so that they can lower the cost of ownership, and use that against their competitors. There are other reasons as well, but as was stated above stick to ZF's recommendation, or change it more often if you tow regularly.
Personally, I like to change fluids before what's recommended and usually on intervals I can easily remember. Oil every 5k, diffs, manual trans and transfer cases every 30k and auto trans every 50k. Fluid is cheap compared to a new gearbox.

Ford did the lifetime fluid many years ago. Decades ago, as I recall.
But then, Ford also did type F which they ended up having problems with and dropped it in favor of new specs, new fluid. So not sure their lifetime fluid is really that.

I go by how hard it's been used or what it's been subjected to.
Frankly, as a person who used to rebuild and repair transmissions as part of my job - I can see with the new fluids, new more sealed systems, etc. how they can easily stretch things out. These aren't as open as new transmissions, they operate very differently. More "speeds" also means less slippage between shifts/gears, less heat, clutch packs stay cooler, etc. These aren't grandpa's old THM 350 or C4 or TF727
And some filters were hardly "filters". They ran hot, they slipped during shifts, they were more exposed to the atmosphere.
So it's easy to see why they don't recommend changes every few thousands miles like the old days.

Transmissions are one thing I've never had an issue with as far as wear or breaking, etc. in my own vehicles.

 

[Maximus Gladius]

First change should be done as soon as possible. I got my JTR February 2021. I ordered pan and gasket in April. It arrived 5 months later dirty and missing parts and had put on 20k kms waiting. Ordered another and took a sample of my Mopar 8-9 speed semi-synthetic tranny oil to the lab for analysis @ 24k kms. Here’s my lab result with cross check comparison with a fresh sample. Chances are you have glycol in yours too if the assembly plant was working as clean with yours as it was with mine. You can run your own analysis if you want, if not you can only assume all is well.

My new pan, gasket and fasteners are coming next week and I’ve lined up a transmission company to do a hot flush. I’m switching out the Mopar semi-synthetic with Amsoil Signature Series (spec’d for the 8HP50 and 850RE ZF tranny). It is also in compliance with ZF codes.

I’ve sat down with my service manager at the dealership and had a long conversation about not only that I’m consuming 14 ounces of coolant in my engine during a 10k kms oil change and lab results indicating that fact but now have the lab results showing glycol contamination in the transmission. He said he was “scared to check and see if he has glycol in his 75k kms tranny, it’s also better to hot flush sooner than later. I have absolute right to be concerned and take necessary action to get it out. Chrysler won’t because nothing is broken.” He would like to see another lab analysis after I do the hot flush to see if the glycol is gone. He was not certain if the cooler is rad internal or outside and I haven’t looked. The lab tech said contamination comes via the factory assembly which is very common to see or internal leak. If it’s from the factory, the new oil won’t have glycol in it.

https://www.jeepgladiatorforum.com/forum/attachments/transmission-lab-results-pdf.190790/

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