ZF8 50K Mile Transmission Service -- DIY How-To Instructions

[Heimkehr]

kind of tedious especially lining up the filter with the trans, we were going at it for a few attempts but go it.

Overall about 5.5qts went back into the trans. But didn't measure the fluid coming out.

5.5 quarts is the amount of fluid that should drain out during each service. The same volume should be pumped back in each time, also. This is why at least two fluid & filter changes are recommended (3 is best), so as to maximize the replacement of old fluid with new.

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Tips for next time, unless you've already done so:

1. The two magnets in the pan should be removed, thoroughly cleaned and reinstalled.

2. The two nuts that secure the transmission filter should be snugged, and then backed off barely half a turn...just enough to allow a bit of fore & aft movement, which will in turn make aligning the filter's neck with the corresponding port on the underside of the transmission body that much easier. This is stated in the instruction document that accompanied the filters that I purchased.

Also...what are we looking at in the first two photos? Did you cut open/disassemble the original filter assembly?

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[CptFloridaMan]

5.5 quarts is the amount of fluid that should drain out during each service. The same volume should be pumped back in each time, also. This is why at least two fluid & filter changes are recommended (3 is best), so as to maximize the replacement of old fluid with new.

---------------

Tips for next time, unless you've already done so:

1. The two magnets in the pan should be removed, thoroughly cleaned and reinstalled.

2. The two nuts that secure the transmission filter should be snugged, and then backed off barely half a turn...just enough to allow a bit of fore & aft movement, which will in turn make aligning the filter's neck with the corresponding port on the underside of the transmission body that much easier. This is stated in the instruction document that accompanied the filters that I purchased.

Also...what are we looking at in the first two photos? Did you cut open/disassemble the original filter assembly?

To answer your questions, it was whining on hard turns from being low so I’m not sure how low it was other than the pump whining when downshifting from 8th-5th or during a hard right hand turn, and it still does it if i’m pushing it hard into the corner in a higher rpm but that makes sense if the fluid gets sloshed over to one side. Might wanna get a PPE pan in the future.
I’ll be opening her back up soon to do new fluid and filter again soon just gonna let fall come first as it’s a bit rough to do work under the jeep with the heat. But I plan for it either in the fall or early spring.

Magnets were removed and cleaned also, first thing I checked(also made sure to reinstall), and the backing off half a turn felt weird to do. Felt a little backwards, but the filter was able to move laterally which helped some to line it up but still had to fiddle with moving it and lining it up.

And yes, the first two photos are the original filter after I tore into it. Never seen photos of one split open so I thought it would be nice to share.

 

[CptFloridaMan]

Little update, going to try to put more fluid in as I can still hear the pump whine, can only kinda hear it once temps climb to 180+ and doing 70mph+.

So I’m hoping it’s just a bit of air in the system and the extra bit of fluid helps etc. But I do have a few questions.

Being that it’s very warm in central florida, the trans climbs to 120 rather quickly. So it’s very much a race against the clock. The first fill; we got it up to 97° by the time we finished the sequence post initial fill, and by the time we finished the second fill it climbed to 116° pretty quick. My plan to get more fluid in(if it is a weebit low) is to take a quick spin up to 45mph to get it into 8th and all the fluid cycled through the trans. And then quickly hustle back home to finish it. My question though, does anyone know if any valves close at 120° that would hinder me from putting more fluid in?

Next question, how are the PPE pans and filters compared to oem? Not necessarily in a heat aspect but a capacity and fluid pick up sense. It looks like the filter is deeper in the pan which seems like it would mitigate the pump whine when it’s trying to suck in fluid from the inlet- less likely to get air in the system no?

 

[CptFloridaMan]

Ok so ZF replied, the trans apparently has the valve open at 170°F for the cooler. But they still say to only fill between 90-120. Gonna try to get it taken care of friday early in the AM since forecast says it’ll be under 80° in the morning before 8a; trying to buy some time to scoot down the road and back.

 

[Heimkehr]

My question though, does anyone know if any valves close at 120° that would hinder me from putting more fluid in?

Next question, how are the PPE pans and filters compared to oem? Not necessarily in a heat aspect but a capacity and fluid pick up sense. It looks like the filter is deeper in the pan which seems like it would mitigate the pump whine when it’s trying to suck in fluid from the inlet- less likely to get air in the system no?

As your subsequent post makes plain, Gabriel, you're simply not going to get around the prescriptive, temperature-based maintenance procedure for the 8-speed transmission. Know that you can shift through the gears while the vehicle is still in the garage (Step #13 on p. 1.) Yes, #17 compels a thorough cool-down after a brief drive. Having been stationed in Florida, I know that can take a little while.

The aftermarket transmission pans are rarely mentioned or seen here on the forum. If they provided real added value, the subject would have more traction than it does. The stock pan and filter design is proven and functional. Yes, the absence of a drain plug on the OEM pan could be considered a minor inconvenience. However, replacing the transmission fluid requires a new filter as a matter of course, so a drain plug would only accommodate those owners seeking a shortcut.

A healthy transmission with the proper fluid level shouldn't whine, no matter that the stock parts are being used.

 

[CptFloridaMan]

As your subsequent post makes plain, Gabriel, you're simply not going to get around the prescriptive, temperature-based maintenance procedure for the 8-speed transmission. Know that you can shift through the gears while the vehicle is still in the garage (Step #13 on p. 1.) Yes, #17 compels a thorough cool-down after a brief drive. Having been stationed in Florida, I know that can take a little while.

The aftermarket transmission pans are rarely mentioned or seen here on the forum. If they provided real added value, the subject would have more traction than it does. The stock pan and filter design is proven and functional. Yes, the absence of a drain plug on the OEM pan could be considered a minor inconvenience. However, replacing the transmission fluid requires a new filter as a matter of course, so a drain plug would only accommodate those owners seeking a shortcut.

A healthy transmission with the proper fluid level shouldn't whine, no matter that the stock parts are being used.

The fill I did got up to 116° before i finished. I guess I didn’t overfill enough for the .5L though. Will attempt it again this week though. The waiting for parts is the annoying part in florida though, so I have to to take advantage of the “cool” morning at 80° and do it quickly. Will update once I attempt to do it again.

But for the overfilling part, how fast should it be flowing out of the trans for it to be “correct”?

 

[Heimkehr]

But for the overfilling part, how fast should it be flowing out of the trans for it to be “correct”?

That's the easy part, insomuch that it can't really be overfilled. As is the case when adding gear oil to the differentials, you'll simply pump transmission fluid into the fill hole until it begins to drip out...slowly or quickly, it won't matter. At that point, you've added as much fluid as the design will allow you to do.

 

[CptFloridaMan]

So while researching cause I still need to do the 3rd fluid level/fill check after the second fill. Found this video explaining to level the trans, not the truck/jeep. Is that part of the process for our jeeps too? Also saw some bimmer forum guys saying they did the same as well. At 7:17 he starts explaining it.

 

[Grayhound]

I appreciate all the info here.

Just did an oil and filter change at 57k miles. I was surprised as the amount of metal paste.

It was a fairly straightforward process. I only used 4.5 qrts of Mopar 8&9. I was at the low end temp spectrum when I started.

The bolts for the pan break easy... this took more time to deal with than the oil change.

 

[redsyphon]

Just did this service for my 2018, but now there is a rattle when it shifts gears.

No vibrations or hesitation in changing gears, but the rattle (kinda like a loose piece of metal in a jar/can) is present from gear 2-8 at shift points (Nothing in Reverse or Neutral).

I pulled the pan to make sure there wasn't anything loose and the fill neck was properly seated, but it all looked fine.

Anyone have ideas?
It feels ok whilst driving, but I don't want to damage it if it's not

Attached a few pictures when I pulled the pan the 2nd time to check nothing was amis. I couldn't find anything so...

 

[CptFloridaMan]

You sure the rattles coming from the trans? Can’t imagine the trans rattling but maybe a heatshield or something under the hood?

 

[Old Dogger]

I just read through this Thread. No thanks, I will just have my Dealer change it..........

 

[roaniecowpony]

I just read through this Thread. No thanks, I will just have my Dealer change it..........

The directions for changing the fluid are really not much different than a GM trans. The temperature range to check it after a fill is a bit different but pretty much every thing else are steps that you do on most automatics.

 

[Heimkehr]

Just did this service for my 2018, but now there is a rattle when it shifts gears.

No vibrations or hesitation in changing gears, but the rattle (kinda like a loose piece of metal in a jar/can) is present from gear 2-8 at shift points (Nothing in Reverse or Neutral).

I pulled the pan to make sure there wasn't anything loose and the fill neck was properly seated, but it all looked fine.

Did you check the fluid level, whilst it was at the correct temperature to do so, after the vehicle had a few miles accumulated after the fluid & filter change?

I just read through this Thread. No thanks, I will just have my Dealer change it..........

My dealer refused to do so, leaning heavily on the "Lifetime Fill" language in the Owner's Manual. I found this thread and got to work. It's a straightforward process.

 

[redsyphon]

Did you check the fluid level, whilst it was at the correct temperature to do so, after the vehicle had a few miles accumulated after the fluid & filter change?



My dealer refused to do so, leaning heavily on the "Lifetime Fill" language in the Owner's Manual. I found this thread and got to work. It's a straightforward process.

I did a 4th refill after making sure it was warm (same as last time), but this time it took another 1/2qrt.

Problem solved. Thankfully it was a simple fix. Thanks for the reply as it made me double/triple guess myself

Legit, the hurricane just came through last night and took.out our back fence... the Jeep was still making me more sad than the fence lol. Now I'm happy and don't even care (at least for today).

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