First Transmission Drain and Fill

[713gladiator]

So, my Jeep currently has 57K miles and I figured now is a good time to drain the transmission fluid.
I've never performed a transmission drain/fill and heard horror stories about transmissions being destroyed.
Friends were telling me that it's a lifetime fluid and doesn't need to be flushed or drained.

Well, I've been on this forum reading how the ZF engineers recommend a fluid service at 60K - 80K and figured since they are the ones that designed the transmission, they would know best.

So I jumped on youtube and watched a tutorial that made it look fairly simple.
I stopped by my dealership, ordered a new transmission pan gasket and filter.
Order the fluid on Amazon and started my first experience into draining a transmission.

As I drained the fluid, I measured the total mL on a scale and noted it.
I also measured how much the old transmission filter weighed in mL vs the new old filter so I could compensate for the amount of fluid still in the filter.
In total, I drained 4,275 mL which according to google, is approx 4.5 qts

What I wasn't expecting was how many quarts I was using to fill the transmission back up.
Before I began the shifting process to warm the transmission up, I measured each quart before and after I used it.
What I noticed was, each quart (bottle) of fluid I measured before filling, was approx. 855 mL and not the 946mL as shown on the bottle.

In my first round, I used 4 quarts (bottles) before some fluid started to drip out.

I plugged up the pan and warmed up the transmission to 88 degrees. Left it in Park and started to fill again until fluid began to drip out again.
I put another 1 and 1/2 quarts (bottles) bringing the total to 5 and 1/2 quarts (bottles).

At this point I was concerned that I either overfilled the transmission or my transmission came from the factory with a low amount.

Well, this is where I went back and looked at the before and after amounts for each of the quarts I used.
Each quart still had some fluid remaining. Taking that into account, I was able to total up the actual mL used and even though I used 5 and 1/2 bottles, I still only used 4,290 mL.

At this point I decided to start filling up each of the bottles with the old transmission fluid and sure enough, I filled them all back up to the exact amount (or pretty dang near it) they originally came filled.

After I confirmed that I added back the amount I drained, I plugged the transmission fill hole back up.
I test drove it on the highway for around 10 minutes and the transmission shifted very smooth thru all the gears.

Now, my only concern is, when I inspected the plastic drain pan, I noticed a few metal bits.

Anyone think this is something I should be worried about?



SERVICE UPDATE
September 12th, 2024
Current Mileage: 68,500
No issues
Transmission runs exceptionally well
Shifts are smooth between all gears

I plan to do another transmission drain and fill at 80,000 miles which I expect to happen around November 2025. That will be 2 years from when I performed my first drain and fill. That will leave me with approx 21% of the original fluid. I'll do another drain and fill at 100,000 miles around November 2027

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[Stuntman Mike]

I assume the longer piece is just a flash which has not been removed during production.
So I wouldn't worry about it, specifically if everything is running smooth.

Just recently talked to a friend who is working as a design engineer in ZF, Friedrichshafen and he was telling exactly what you mentioned above. He recommended oil change at 80-100 K KM.

 

[Maximus Gladius]

OP, now is a good time to check the oil level another way and good on ya for grabbing this bull by the horns and doing this yourself!

Level the frame side to side and front to back with back wheels off the ground a couple inches. Have some fluid ready to insert when fill plug is pulled.

Start the engine and press the traction control “OFF” and pull up your temp gauges to see the transmission temp. Decide in your mind what temperature in that “temp window” you want your fluid level plugged off at. *The cooler end is better than the hotter end.

Now, slide underneath and pull the drain plug. (Transmission is cold because you didn’t just start the engine and sit there in the cab) If nothing comes out, fill it up till fluid dribbles out. If however, fluid is coming out, let it. It’s all good and now put the plug back in and wait for the fluid temp to reach the zone you want to run through the gears. There should be a temp sticker on the side of the transmission pan below the fill hole. This part is important.

Once you’ve reached the acceptable temp, put your foot on the brake and hold it there, drop it in “R” for 5-10 seconds, then “N” and bring up RPM to 2000 RPM (brake off) 5-10 seconds, then brake on, drop in “manual drive 1”, brake off and RPM to 2000 5-10 seconds, then shift to 2nd 5-10 seconds then apply brake and stop wheels. Put in park and get underneath and pull the fill plug. If it’s not dribbling out, fill it up. If it is dribbling out, let it till it’s just barely a trickle, plug it and you’re done.

 

[DanW]

OP, now is a good time to check the oil level another way and good on ya for grabbing this bull by the horns and doing this yourself!

Level the frame side to side and front to back with back wheels off the ground a couple inches. Have some fluid ready to insert when fill plug is pulled.

Start the engine and press the traction control “OFF” and pull up your temp gauges to see the transmission temp. Decide in your mind what temperature in that “temp window” you want your fluid level plugged off at. *The cooler end is better than the hotter end.

Now, slide underneath and pull the drain plug. (Transmission is cold because you didn’t just start the engine and sit there in the cab) If nothing comes out, fill it up till fluid dribbles out. If however, fluid is coming out, let it. It’s all good and now put the plug back in and wait for the fluid temp to reach the zone you want to run through the gears. There should be a temp sticker on the side of the transmission pan below the fill hole. This part is important.

Once you’ve reached the acceptable temp, put your foot on the brake and hold it there, drop it in “R” for 5-10 seconds, then “N” and bring up RPM to 2000 RPM (brake off) 5-10 seconds, then brake on, drop in “manual drive 1”, brake off and RPM to 2000 5-10 seconds, then shift to 2nd 5-10 seconds then apply brake and stop wheels. Put in park and get underneath and pull the fill plug. If it’s not dribbling out, fill it up. If it is dribbling out, let it till it’s just barely a trickle, plug it and you’re done.

Where did you get this info? A service manual?

 

[Mister Lamb]

Where did you get this info? A service manual?

His lawsuit

 

[Maximus Gladius]

Where did you get this info? A service manual?

This is spot on. I can confirm the fluid levels are correct when doing this.

 

[Maximus Gladius]

His lawsuit

4 transmissions later in 75k kms, the fluid levels were spot on in all of them. What the heck was going on with them ??? had me learning the fluid level technique in under 30 min.

It takes more time now waiting for the temps to get to the right place then it is to get the truck raised and level things up. In every case of the 4 transmissions levels were too high to begin with and was corrected and in every failure and brought in, (except the 4th transmission I have now that’s awesome) the tech determined the fluid levels were good.

The condition of these transmissions (the whine I was hearing in 1st and 2nd) had me diligent and doing oil analysis reports every 5-10k to watch the wear numbers so I had to be good at knowing how to check the level’s correctly.

The relationship with Chrysler and two dealerships started off very heated and rocky but now that I found the dealership I trust to handle my drivetrain concerns and the relationship with Chrysler has advanced so much better, there is respect that’s given in both directions.

Basically, the law suit didn’t materialize because it would have taken 2 years to get to court, because of COVID delays. My insurance company, at that time, approved replacing the engine and first transmission.

I think because all of my mechanical issues (2 engines, 3 transmissions and 3 power steering pumps) all happened during Covid (4th transmission is new, outside Covid), quality issues in employees, manufacturing, supply and control was out the window and a lot of these components had issues.

 

[Madtom]

What I wasn't expecting was how many quarts I was using to fill the transmission back up.
Before I began the shifting process to warm the transmission up, I measured each quart before and after I used it.
What I noticed was, each quart (bottle) of fluid I measured before filling, was approx. 855 mL and not the 946mL as shown on the bottle.

Anyone think this is something I should be worried about?

Great writeup. only thing is when you say the Quart container only contains 855ml..... you are incorrect..... It weighs 855gms (weight)and contains 945ml (volume)........ Weight and Volume are looking for different things

 

[713gladiator]

Great writeup. only thing is when you say the Quart container only contains 855ml..... you are incorrect..... It weighs 855gms (weight)and contains 945ml (volume)........ Weight and Volume are looking for different things

And this is why I'm not an engineer
Thank you for the clarification @Madtom

 

[aceinfinity]

So, my Jeep currently has 57K miles and I figured now is a good time to drain the transmission fluid.
I've never performed a transmission drain/fill and heard horror stories about transmissions being destroyed.
Friends were telling me that it's a lifetime fluid and doesn't need to be flushed or drained.

Well, I've been on this forum reading how the ZF engineers recommend a fluid service at 60K - 80K and figured since they are the ones that designed the transmission, they would know best.

So I jumped on youtube and watched a tutorial that made it look fairly simple.
I stopped by my dealership, ordered a new transmission pan gasket and filter.
Order the fluid on Amazon and started my first experience into draining a transmission.

As I drained the fluid, I measured the total mL on a scale and noted it.
I also measured how much the old transmission filter weighed in mL vs the new old filter so I could compensate for the amount of fluid still in the filter.
In total, I drained 4,275 mL which according to google, is approx 4.5 qts

What I wasn't expecting was how many quarts I was using to fill the transmission back up.
Before I began the shifting process to warm the transmission up, I measured each quart before and after I used it.
What I noticed was, each quart (bottle) of fluid I measured before filling, was approx. 855 mL and not the 946mL as shown on the bottle.

In my first round, I used 4 quarts (bottles) before some fluid started to drip out.

I plugged up the pan and warmed up the transmission to 88 degrees. Left it in Park and started to fill again until fluid began to drip out again.
I put another 1 and 1/2 quarts (bottles) bringing the total to 5 and 1/2 quarts (bottles).

At this point I was concerned that I either overfilled the transmission or my transmission came from the factory with a low amount.

Well, this is where I went back and looked at the before and after amounts for each of the quarts I used.
Each quart still had some fluid remaining. Taking that into account, I was able to total up the actual mL used and even though I used 5 and 1/2 bottles, I still only used 4,290 mL.

At this point I decided to start filling up each of the bottles with the old transmission fluid and sure enough, I filled them all back up to the exact amount (or pretty dang near it) they originally came filled.

After I confirmed that I added back the amount I drained, I plugged the transmission fill hole back up.
I test drove it on the highway for around 10 minutes and the transmission shifted very smooth thru all the gears.

Now, my only concern is, when I inspected the plastic drain pan, I noticed a few metal bits.

Anyone think this is something I should be worried about?

Why did you do this ? Was it calling for it in the manual?

 

[713gladiator]

Why did you do this ? Was it calling for it in the manual?

Jeep says lifetime fluid. What's lifetime? Jeep does not specify if lifetime means until I die (my lifetime) or lifetime of the powertrain warranty (5yrs / 60K miles)

However, you know who does say when the transmission should be serviced? The engineers/makers of the actual transmission, ZF Friedrichshafen AG.

As far as I'm concerned, I'm going to go by what the actual designers of the transmission recommend, which is 50K - 60K miles or every 8 years


How To Change The Oil In A ZF 8-Speed Transmission

The ZF 8-Speed Transmission Fluid and Filter Change

The cost of a new transmission is $4K - $5K
The cost to drain and fill is $250

Honestly, I'm glad I did it. The fluid was very dark compared to how clear the new fluid is.
The transmission holds about 10 quarts, so I only drained about 1/2.

It was relatively easy and I am far from being a mechanic. I'm just a desk monkey that watched a few youtube videos that showed how to service the transmission.

I'll probably drain and fill again at 75K - 80K miles since I only drained around 5 and 1/2 quarts.

 

[DanW]

What is the rated fluid capacity for this transmission?

 

[Gren71]

Mam i REEEAAALLLLYYYYY need to do this ?‍ im just shy of 104,000 miles…i bought the stuff to do this when i was around 80k haha

 

[aceinfinity]

Jeep says lifetime fluid. What's lifetime? Jeep does not specify if lifetime means until I die (my lifetime) or lifetime of the powertrain warranty (5yrs / 60K miles)

However, you know who does say when the transmission should be serviced? The engineers/makers of the actual transmission, ZF Friedrichshafen AG.

As far as I'm concerned, I'm going to go by what the actual designers of the transmission recommend, which is 50K - 60K miles or every 8 years


How To Change The Oil In A ZF 8-Speed Transmission

The ZF 8-Speed Transmission Fluid and Filter Change

The cost of a new transmission is $4K - $5K
The cost to drain and fill is $250

Honestly, I'm glad I did it. The fluid was very dark compared to how clear the new fluid is.
The transmission holds about 10 quarts, so I only drained about 1/2.

It was relatively easy and I am far from being a mechanic. I'm just a desk monkey that watched a few youtube videos that showed how to service the transmission.

I'll probably drain and fill again at 75K - 80K miles since I only drained around 5 and 1/2 quarts.

Maybe you should leave things alone. I swear it’s people like this that complain when stuff breaks.

 

[713gladiator]

Maybe you should leave things alone. I swear it’s people like this that complain when stuff breaks.

Everything in life has a risk.

To me, this is a low risk process that the engineers themselves specifically say should be done between 50K - 75K miles

And if it breaks after 60K miles, who is going to fix it? Not Jeep. It's out of warranty.
I'll take the risk and do what the engineers recommend.

The transmission is an 8HP50 aka 850RE

Here is the ZF Service Information directly from the designers

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