Transmission Oil Change Question

[hkatrib]

Hi,
On my last service visit at the dealer, I asked when is the transmission oil change due? And the answer was that the ZF guarantees oil for life no need to change!!
Is that true? What is your experience?

 

[Robr651]

Life means the life of your warranty not the life of your vehicle. Dealerships are money making enterprises that want to do zero work on your vehicle while it’s under warranty. They want it to fail off of warranty so you pay full price for repairs or dump it and buy another one from them. ZF doesn’t claim it’s a lifetime fluid.

 

[hkatrib]

Life means the life of your warranty not the life of your vehicle. Dealerships are money making enterprises that want to do zero work on your vehicle while it’s under warranty. They want it to fail off of warranty so you pay full price for repairs or dump it and buy another one from them. ZF doesn’t claim it’s a lifetime fluid.

Good point and that what I expect.
So at which interval is it due?

 

[Robr651]

Driving style / towing etc all play factors. There’s tons of info on ZF 8 speeds on multiple forums. 50k miles is probably a good low estimate from average driving / use. My thought is always filters and fluid are cheap, parts are not. (Even though that fluid is fairly expensive).

 

[stumblinhorse]

Draining and refilling a ZF trans is not like the old automatics. So a couple of things. Most dealers do it wrong or won’t do it at all. Second, any mechanic that uses the word “flush” with an estimate, you should run, not walk, away. Third, the zf8hp75 service is costly. Parts alone will be $300-500 give or take.

All of that aside it should be done around 50k miles of normal driving. And to do it properly it is a rinse and repeat procedure. So assume the parts are 2x.

 

[Bobo57]

Draining and refilling a ZF trans is not like the old automatics. So a couple of things. Most dealers do it wrong or won’t do it at all. Second, any mechanic that uses the word “flush” with an estimate, you should run, not walk, away. Third, the zf8hp75 service is costly. Parts alone will be $300-500 give or take.

All of that aside it should be done around 50k miles of normal driving. And to do it properly it is a rinse and repeat procedure. So assume the parts are 2x.

What parts cost $500 for a trans fluid change?

 

[stumblinhorse]

What parts cost $500 for a trans fluid change?

Fluid, pan, gasket and filter is $300. Then 2x or 3x to do a complete fluid swap.

 

[Bobo57]

Fluid, pan, gasket and filter is $300. Then 2x or 3x to do a complete fluid swap.

So why do you have to replace the pan?

 

[stumblinhorse]

So why do you have to replace the pan?

Unless something has changed since I did my other zf8, the filter is integrated into the pan. I also think the pan doesn’t have a real plug, it is a plastic pan with a single use drain plug.

 

[Leftfield]

So why do you have to replace the pan?

Just did a double change on my 8HP75 at 50k miles. The pan and filter come as an assembly. Here are my notes on procedure, parts & quantities:

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

03 July 2023 - Edited to include all tools and steps needed on the first page. Note: unless the pan is already leaking, you will not need a new pan gasket. I have had my pan on and off 3x now with no issues--it is reusable. Tools and parts needed: 10mm socket for filter nuts 8mm hex (Allen...

www.jlwranglerforums.com

6 Qts Mopar 8/9 Transmission Fluid 68218925AB~$15/Qt Amazon
About 5.5-5.75 qts / change (out of 9.5 qt dry fill)
Alt fluid: ZF Lifeguard 8 ~$13/Qt RockAuto
Mopar transmission pan w/ filter: 68362041AC ~$132.00 Mopar online
Notes: Shake fluid before pouring

On the first change I replaced the pan; fair amount of sludge present. The fluid had darkened but still had a tinge of green.

Drove it 20-30 miles & did the second change. For the second change just dropped the pan, emptied the fluid and bolted it back on. It was still very clean. A double change replaces about 85% of the fluid.

LF

 

[stumblinhorse]

Direct link to @Leftfield notes

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

How confident was I when I did the transmission fluid change. I changed it at night, let it cool over night. Warmed it up in the morning and topped it off. Then drove 180 miles, bought a new camper and towed it home.

www.jlwranglerforums.com

 

[hkatrib]

Just did a double change on my 8HP75 at 50k miles. The pan and filter come as an assembly. Here are my notes on procedure, parts & quantities:

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

03 July 2023 - Edited to include all tools and steps needed on the first page. Note: unless the pan is already leaking, you will not need a new pan gasket. I have had my pan on and off 3x now with no issues--it is reusable. Tools and parts needed: 10mm socket for filter nuts 8mm hex (Allen...

www.jlwranglerforums.com

6 Qts Mopar 8/9 Transmission Fluid 68218925AB~$15/Qt Amazon
About 5.5-5.75 qts / change (out of 9.5 qt dry fill)
Alt fluid: ZF Lifeguard 8 ~$13/Qt RockAuto
Mopar transmission pan w/ filter: 68362041AC ~$132.00 Mopar online
Notes: Shake fluid before pouring

On the first change I replaced the pan; fair amount of sludge present. The fluid had darkened but still had a tinge of green.

Drove it 20-30 miles & did the second change. For the second change just dropped the pan, emptied the fluid and bolted it back on. It was still very clean. A double change replaces about 85% of the fluid.

LF

Great and very helpful write up! I would like to ask about one detail, did you re-use the old pan bolts? And how much did you torque them to?

 

[stumblinhorse]

Great and very helpful write up! I would like to ask about one detail, did you re-use the old pan bolts? And how much did you torque them to?

Pan comes with new bolts. 85-90in/lbs.

 

[hkatrib]

Pan comes with new bolts. 85-90in/lbs.

Thanks

 

[Leftfield]

Great and very helpful write up! I would like to ask about one detail, did you re-use the old pan bolts? And how much did you torque them to?

The write-up referenced above is aimed a little more at the 3.6 and 2.0 installations but is largely common with the 8HP75 used with the 392. I added a post specific to the 392 (below) including the 8HP75 pan bolt tightening sequence:

https://www.jlwranglerforums.com/fo...ow-to-instructions.94302/page-26#post-2891179

There might be some variation in the pans...?
On my 2021 the OEM pan was steel and the OEM replacement pan that arrived was also steel. It did not come with bolts, nor did I see anything in the ZF instructions indicating to replace the bolts. Maybe its a steel pan vs plastic pan thing?

Here are the ZF torque specs for the various pan options. The 10Nm listing below is equivalent to 88.5 inlb as cited by @stumblinhorse.

This chart also indicates that for the steel pan the filter is a separate part, which appears to be outdated. Benny @ AllMoparParts indicated that the filter is no longer sold separately and is superseded by a pan and filter assembly.

LF

 

[hkatrib]

The write-up referenced above is aimed a little more at the 3.6 and 2.0 installations but is largely common with the 8HP75 used with the 392. I added a post specific to the 392 (below) including the 8HP75 pan bolt tightening sequence:

https://www.jlwranglerforums.com/fo...ow-to-instructions.94302/page-26#post-2891179

There might be some variation in the pans...?
On my 2021 the OEM pan was steel and the OEM replacement pan that arrived was also steel. It did not come with bolts, nor did I see anything in the ZF instructions indicating to replace the bolts. Maybe its a steel pan vs plastic pan thing?

Here are the ZF torque specs for the various pan options. The 10Nm listing below is equivalent to 88.5 inlb as cited by @stumblinhorse.

View attachment 42848

This chart also indicates that for the steel pan the filter is a separate part, which appears to be outdated. Benny @ AllMoparParts indicated that the filter is no longer sold separately and is superseded by a pan and filter assembly.

LF

Awesome! Thanks bunch!