How often to change transmision fluid?

[Jeep Junkie]

This Pacifica made it to 500k miles but blew the transmision in a little over 100k miles. The guy blames that on not changing fluid early enough, otherwise ZF 8 spd would have made it to 500k miles too. He says 30-40k miles is the best interval. What do guys think?

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[kah.mun.rah]

My gasket is leaking so it looks like I will be changing mine at 70K. Otherwise I do it at 100K miles. The T-case I do at every 30K (recommended every 60K), and axle fluid every 25K (recommended every 40K).

 

[Jeep Junkie]

My gasket is leaking so it looks like I will be changing mine at 70K. Otherwise I do it at 100K miles. The T-case I do at every 30K (recommended every 60K), and axle fluid every 25K (recommended every 40K).

Why is it leaking?

 

[kah.mun.rah]

Why is it leaking?

I'll find out once I change the gasket. My guess is that it has a loose bolt, a stripped bolt, or a misaligned gasket. I don't think I have hit the pan on anything but that is a possibility too. FYI, I just looked it up and it looks like they recommend changing the trans fluid every 60K miles so I guess I am overdue.

 

[Jeep Junkie]

I'll find out once I change the gasket. My guess is that it has a loose bolt, a stripped bolt, or a misaligned gasket. I don't think I have hit the pan on anything but that is a possibility too. FYI, I just looked it up and it looks like they recommend changing the trans fluid every 60K miles so I guess I am overdue.

I see. Hopefully it is just that and your ZF keeps rocking.

 

[Jeep Junkie]

I'll find out once I change the gasket. My guess is that it has a loose bolt, a stripped bolt, or a misaligned gasket. I don't think I have hit the pan on anything but that is a possibility too. FYI, I just looked it up and it looks like they recommend changing the trans fluid every 60K miles so I guess I am overdue.

Parts on Mopar website.

https://store.mopar.com/oem-parts/m...ter-68417054ab?c=bD0xJm49U2VhcmNoIFJlc3VsdHM=

https://store.mopar.com/oem-parts/mopar-automatic-transmission-fluid-68218925ab

https://store.mopar.com/oem-parts/mopar-oil-pan-gasket-68522534aa?c=bD0xJm49U2VhcmNoIFJlc3VsdHM=

 

[GW’s JL]

ZF recommends 50k-80k. Jeep claims lifetime. I’ll be servicing mine at 40k.

 

[kah.mun.rah]

I see. Hopefully it is just that and your ZF keeps rocking.

It's just a little seepage at the seal, not even dripping. Most people wouldn't even notice and those that do, most wouldn't bother, but I am particular about those things.

 

[Heimkehr]

@Jeep Junkie
The ZF docs that I have in the Jeep's binder mention performing a fluid & filter change approx. every 60K miles. That's the interval that I have used and will continue to use.

I've done the job myself because my dealer refused the work, leaning heavily on the [fictitious, IMO] "Lifetime fill" language evident in the Owner's Manual.

When the time comes due, I'll replace the fluid & filter at least twice, with 1K miles in between. The system capacity is 9 quarts, but only 5.5 quarts, on average, will drain out when following the prescribed service procedure. Thus, performing at least two fluid & filter replacements in close succession (3 is best) maximizes the removal of the old fluid. Something to keep in mind.

 

[X35]

I’m going to go with an every 25K mile trans filter/fluid change schedule with mine. My theory is that the 25K schedule will allow for fresh fluid without ever having fluid left in the trans that was stressed to the max mileage. This works for my OCD, YMMV

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