ZF8 50K Mile Transmission Service

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Sep 26, 2010
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I changed the filter and fluid recently and not a bad job aside from having to pull two of the three MC skid plates to get to the transmission and transfer case (I changed its fluid as well). If you loosen the pan bolts all the way around and then loosen the back bolts a little more (towards the rear of the Jeep) this will allow the fluid to drain and it will be less messy. I had to rotate the pan 90° to get it out from under the 3.6L exhaust pipe. A drain plug would have made the fluid dump much easier. I used a Husky flat bin which measured 18W x 36L x 8H and it caught all of the fluid without spilling any.

I used a Mopar filter and ZF Lifeguard 8 fluid and it took about 4 QTs. I bought a pump up sprayer based upon feedback from others to install the new fluid, but I used a Flo Tool nozzle (https://smile.amazon.com/Hopkins-10106B-FloTool-Filler-Refill/dp/B000EH4UXM) with no issues and it fit the ZF8 fluid bottles. The two magnets in the pan had a fair amount of metal "paste" on them, but nothing that I did not expect to see after 50K miles. Note the magnets are simply held in the pan via magnetic force and are not permanently attached which makes cleaning them a simple process. There was no debris in the pan which is a good indication the clutches are not shedding material.

FCA states to snug the filter nuts and then back off 1/2 round which I did (they are locking flange nuts and new ones are included with the filter). This is so the filter can move horizontally slightly to allow for alignment of the filter nozzle into the valve body housing. I lightly lubed the o-ring on the filter with new fluid and then mounted the pan.

ZF states the pan bolts should be 12nm and FCA states 10nm, so I split the difference and went with 11nm and followed the torque sequence in the attached PDF. Although I have a new gasket, I re-used the old one because it was in great shape. I used the process documented here (https://aftermarket.zf.com/remoteme...38411/si-zf-si-oelwechselkit-8hp-50130-en.pdf) to refill and check the fluid. I plan to run it for about 5K miles and dump the fluid again.

With all of that said, the fluid was VERY dirty as compared to the new fluid (see pictures). I would not under any circumstances run the fluid and filter for 100K miles or "lifetime" as FCA states--note that ZF states the transmission should be serviced at 60K miles. I think that FCA is doing a serious disservice to owners when they say "lifetime" fill--which is complete and utter bovine scatology.


Left Pan Magnet:

20220521_151552.jpg

Right Pan Magnet:

20220521_151556.jpg

Clean Pan With New Fliter:

20220521_153050.jpg

Old Fluid In Drain Pan:

20220521_163355.jpg


Old Fluid On White Paper Towel:

20220521_173030.jpg

New Fluid Versus Old:

20220521_175316.jpg
 
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Nice write up. I'm a big fan of dropping the factory fill of ATF early. I did my 2016 Rubicon @ 10K miles. Odds are the next vehicle I own will be bought new and have a ZF 8 speed transmission. I'll probably drop it at 25K then do it every 50K after that. I'm sure that's overkill to some. ;)
 
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I changed the trans fluid on my friends Mercury Marauder that had 40K on it and the trans fluid was nice and red. Of course this car has an external trans cooler, I am wondering if Carbonsteel's car had an external trans cooler on it?
 

CarbonSteel

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I changed the trans fluid on my friends Mercury Marauder that had 40K on it and the trans fluid was nice and red. Of course this car has an external trans cooler, I am wondering if Carbonsteel's car had an external trans cooler on it?
Yes; it does and the fluid temperatures have been nominal except for when I am off-roading where they rise some due to slow movement. The ZF fluid just seems to change from the light green to darker (and darker as time/miles stack on) pretty easily. It just highlights (from my POV) that there is no such thing as a "lifetime fill" and ZF agrees, but FCA is following the typical "no maintenance" mantra.
 

CarbonSteel

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Nice write up. I'm a big fan of dropping the factory fill of ATF early. I did my 2016 Rubicon @ 10K miles. Odds are the next vehicle I own will be bought new and have a ZF 8 speed transmission. I'll probably drop it at 25K then do it every 50K after that. I'm sure that's overkill to some. ;)
There is a guy on the Wrangler forum who did exactly that:

EDIT- I would not consider it to be overkill. I plan to drive it about 5K miles and dump the fluid again and repeat once more to try and change as much of the fluid as I can.

 
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Yes; it does and the fluid temperatures have been nominal except for when I am off-roading where they rise some due to slow movement. The ZF fluid just seems to change from the light green to darker (and darker as time/miles stack on) pretty easily. It just highlights (from my POV) that there is no such thing as a "lifetime fill" and ZF agrees, but FCA is following the typical "no maintenance" mantra.
Ok, so you basically this is not from normal driving, regardless, like you, I am not a fan of the so called Lifetime Trans Fluid. This is a gimmick that the maker of your car knows that your transmission will be fine just beyond the warranty and after that, watch out.
 

CarbonSteel

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Ok, so you basically this is not from normal driving, regardless, like you, I am not a fan of the so called Lifetime Trans Fluid. This is a gimmick that the maker of your car knows that your transmission will be fine just beyond the warranty and after that, watch out.
The vast majority would "normal" driving. You really do not stack on lots of miles when off-roading, though there are some hours. I would guess it is a 95/5 split.
 
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The vast majority would "normal" driving. You really do not stack on lots of miles when off-roading, though there are some hours. I would guess it is a 95/5 split.
Is there a fan in front of this trans cooler that is external on your car? The reason I ask is that my parents have a 2015 Chrysler 200C

Can you determine the trans temp during normal driving or do you have to shoot an infrared fun at the trans pan? Again thanks for starting this thread.
 

CarbonSteel

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Is there a fan in front of this trans cooler that is external on your car? The reason I ask is that my parents have a 2015 Chrysler 200C

Can you determine the trans temp during normal driving or do you have to shoot an infrared fun at the trans pan? Again thanks for starting this thread.
The cooler is OEM and is attached to the side of the transmission with lines running to the radiator.

I have gauges that monitor nearly every fluid temperature (except for power steering and I should look into that too). Front/Rear axle are ISS Pro and all others are part of the Rubicon package.
 
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The cooler is OEM and is attached to the side of the transmission with lines running to the radiator.

I have gauges that monitor nearly every fluid temperature (except for power steering and I should look into that too). Front/Rear axle are ISS Pro and all others are part of the Rubicon package.
This is educational, so the external trans cooler is not mounted in front of the radiator? Can you hit the trans pan with an infrared gun?
 

CarbonSteel

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This is educational, so the external trans cooler is not mounted in front of the radiator? Can you hit the trans pan with an infrared gun?
Correct; but there are lines that go to the front to the radiator cooler. Measuring with an infrared gun would not be accurate, the exhaust pipe crosses under the pan.

The temperature being read by the gauge is going to be the most accurate since it is immersed in the fluid stream.
 
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Correct; but there are lines that go to the front to the radiator cooler. Measuring with an infrared gun would not be accurate, the exhaust pipe crosses under the pan.

The temperature being read by the gauge is going to be the most accurate since it is immersed in the fluid stream.
So, basically what is happening here is that under normal driving conditions there is enough airflow under and around your car to cool the trans fluid. Just a thought, maybe with off roading and slow movement there could be more heat with less airflow underneath the exhaust pipe.

This is all new to me, since I am used to old Chevrolets with a dual exhaust that went right by the transmission.
 

CarbonSteel

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So, basically what is happening here is that under normal driving conditions there is enough airflow under and around your car to cool the trans fluid. Just a thought, maybe with off roading and slow movement there could be more heat with less airflow underneath the exhaust pipe.

This is all new to me, since I am used to old Chevrolets with a dual exhaust that went right by the transmission.
There is a cooler upfront (never checked until now) so that part is covered. When off-roading, the airflow through the radiator is reduced because you are not moving that fast. When coupled with the workload, the temperatures do go up, and they can vary depending on what you are doing, but they are not in any "danger" zone. I have full skid plates so there is minimal air flowing around the transmission so a ribbed pan would not help in that aspect (as an FYI).

Do you have a Jeep or?
 
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There is a cooler upfront (never checked until now) so that part is covered. When off-roading, the airflow through the radiator is reduced because you are not moving that fast. When coupled with the workload, the temperatures do go up, and they can vary depending on what you are doing, but they are not in any "danger" zone. I have full skid plates so there is minimal air flowing around the transmission so a ribbed pan would not help in that aspect (as an FYI).

Do you have a Jeep or?
My parents have a Chrysler 200C and I have to unscrew a plastic plate just to get to the oil pan nut, these engines seem to run hot.
 

CarbonSteel

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My parents have a Chrysler 200C and I have to unscrew a plastic plate just to get to the oil pan nut, these engines seem to run hot.
Ah, ok. Not sure about those, but it may have a plastic transmission pan with a drain plug and may also have the filter built into the pan which means the entire pan has to be changed.
 
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I thought the filter and pan are one unit that must be serviced together. Is the ZF8 on your wrangler different than the Ram’s and other euros?
 
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I changed the ATF in the ZF 8HP in my 2er at 60 miles; next up is the 8HP in the X1.
 
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