ZF8 50K Mile Transmission Service

[4WD]

Install one and it's like screaming to Stellantis: "Restrict my powertrain warranty!"

I was not considering early installation - just purchase and store for later - would have installed with a loop filter then and the pan filter becomes a rock catcher - (already have the filter base) - have done this on GM’s already …
The other thing I like about a drain plug is I park on clean concrete - I can drain and measure with confidence of knowing there are no leaks … The 850RE procedure is annoying …
My GM’s get 5 fresh quarts every Spring - 15 minutes … Clean and neat …

 

[CarbonSteel]

The 850RE procedure is annoying …

To say the very least. It is reminiscent of the Ford 6R80 that I had in my 2010 FX4. On both, you feel rushed to complete it because it does not take long to go from the minimum to maximum temperature (86°F to 122°F on a ZF8) after the intial fill and running it through the gears.

 

[4WD]

To say the very least. It is reminiscent of the Ford 6R80 that I had in my 2010 FX4. On both, you feel rushed to complete it because it does not take long to go from the minimum to maximum temperature (86°F to 122°F on a ZF8) after the intial fill and running it through the gears.

Exactly why I have been waiting for cooler weather … even with a digital meat probe I’ll be crawling in/out to shift gears and read the dash temps …

 

[CarbonSteel]

Exactly why I have been waiting for cooler weather … even with a digital meat probe I’ll be crawling in/out to shift gears and read the dash temps …

It has been pretty cool here in CO, but I have not found that ambient temperature has that much of an effect since it is the engine that is (more or less) driving the temperatures.

The trick is to have everything ready to go. I used the Hopkins Flo Tool nozzle (trimmed the length down some) and it fits the ZF8 bottles (wide mouth) with no issues. Have all of the fluid bottle shaken (not stirred--LOL) and sitting next to the Jeep.

1. Fill until it runs out and reinstall the fill plug
2. Start the Jeep
3. Allow the transmission temperature to hit 86°F
4. Shift through the gears (P, R, N, D, M1, M2) while waiting at least 10 seconds between them
5. Leave the engine running in Park
6. Pull the fill plug and fill until it runs out
7. Reinstall the fill plug
8. Drive it for about 50 miles
9. Check it again idling in park at a temperature of 86°F

While not 100% accurate, after 3 dump and fills, I have about 10% of the old fluid remaining using the formula below.

r = amount of old fluid remaining/total fluid capacity and n = number of fluid changes:

r =(4.4/9.5)^n

There is a point of diminishing returns so I chose 3x as the sweet spot.

 

[The Critic]

Meh---that is less of a concern since they would need to prove the pan caused whatever failure there was.

Technically true, but in the reality, if Tech LIne or a Field Service Engineer is involved with the vehicle and denies a repair (due to it), it is a very uphill battle.

https://www.jeepgladiatorforum.com/forum/threads/fca-canada-voids-transmission-warranty-for-using-amsoil.60204/

I doubt the events would have ended any differently in the US.

For those who will be doing a fluid and filter change, I HIGHLY recommend checking the fluid again after about 50 miles when the air has worked its way out of the lines and the filter. Mine was about 1 pint low after 50 miles and this was after the initial fill, bringing it up to temperature, running it through the gears, checking it again and topping it off while idling in park.

My ZF8 was about 3/4QT low from the factory based upon how much it took to fill it.

That isn't uncommon - I have seen this with various transmissions. I think MB actually tells you to test drive, allow the vehicle to cool, then re-check.

 

[CarbonSteel]

That isn't uncommon - I have seen this with various transmissions. I think MB actually tells you to test drive, allow the vehicle to cool, then re-check.

If only FCA took lessons from MB such as when Daimler owned them, there would have been a number of improvements such as the oil cooler and filter housing being made of 100% aluminum with a plastic cap versus crimping a plastic filter housing into aluminum and wondering why it leaks.

Then again FCA states the ZF8 is "lifetime fill" so there's that...

Amsoil is not on the approved list of fluids for the ZF8 (by either ZF or FCA), so it is not a stretch to have it denied on that account. The pan is a little different, but totally get your point.

 

[4WD]

It has been pretty cool here in CO, but I have not found that ambient temperature has that much of an effect since it is the engine that is (more or less) driving the temperatures.

The trick is to have everything ready to go. I used the Hopkins Flo Tool nozzle (trimmed the length down some) and it fits the ZF8 bottles (wide mouth) with no issues. Have all of the fluid bottle shaken (not stirred--LOL) and sitting next to the Jeep.

1. Fill until it runs out and reinstall the fill plug
2. Start the Jeep
3. Allow the transmission temperature to hit 86°F
4. Shift through the gears (P, R, N, D, M1, M2) while waiting at least 10 seconds between them
5. Leave the engine running in Park
6. Pull the fill plug and fill until it runs out
7. Reinstall the fill plug
8. Drive it for about 50 miles
9. Check it again idling in park at a temperature of 86°F

While not 100% accurate, after 3 dump and fills, I have about 10% of the old fluid remaining using the formula below.

r = amount of old fluid remaining/total fluid capacity and n = number of fluid changes:

r =(4.4/9.5)^n

There is a point of diminishing returns so I chose 3x as the sweet spot.

View attachment 117643

Temperature for me (especially when annoyed )
I have a couple of those fill tubes from the Dana fills …
Thanks …

 

[CarbonSteel]

Temperature for me (especially when annoyed )
I have a couple of those fill tubes from the Dana fills …
Thanks …

LOL - copy that.

 

[MattPersman]

Current msrp is $34.85/qt from Stellantis. With the typical matrix price structure, $48 is pretty common. Usually matrix for a part at this price level is ~150% of msrp.

Funny thing is price is $56 a quart as of today quoting for a service I was doing

 

[4WD]

2020 Jeep 850RE metal pan

1.) has anyone done the ATF on one of these (JL/JT) ? 2.) is there a place to put a B&M aftermarket plug ? 3.) how much ATF did it take (not flushing) ?

bobistheoilguy.com

^^^^^
Think this is still all I will do at 20K - mainly get a look at the magnets - and get them back working if covered up …
Then plan on getting a pan plug in on a fluid/filter swap at 60K …
Already have 7 quarts of Zeus juice …

 

[CarbonSteel]

2020 Jeep 850RE metal pan

1.) has anyone done the ATF on one of these (JL/JT) ? 2.) is there a place to put a B&M aftermarket plug ? 3.) how much ATF did it take (not flushing) ?

bobistheoilguy.com

^^^^^
Think this is still all I will do at 20K - mainly get a look at the magnets - and get them back working if covered up …
Then plan on getting a pan plug in on a fluid/filter swap at 60K …
Already have 7 quarts of Zeus juice …

You will have more than enough. 5.1 has been the magic number for my 3 fluid dumps.

 

[CarbonSteel]

@4WD - here are a few photos. The magnets had 50K of run time on them before cleaning.

You can see the orientation of the filter. There is not a lot of space between the bottom of the filter and the pan.