ZF service recommendations straight from ZF

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Dusty

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A buddy of mine used to get a new company car every 2-3yrs. He was an on-the-road sales exec, and put on a lot of miles visiting distributors, etc. Back in the mid 80's he was supplied with a Caprice/Impala w/V8. For an experiment, after the initial break-in engine oil change he put in Mobil1 and never changed it while he had the car. Nor the filter. He just wanted to see how it would go. This was back in an era when there were lots of magazine and TV ads claiming how amazing Mobil 1 *synthetic* oil was, and you didn't need to change it very often.

He put on like 80k miles, till he got the next car. Obviously he had to add some quarts during those couple years, but he says it wasn't too many. The Mobil-1 always looked really clean, even when he sold it. Now remember, these would have been mostly highway miles. Usually the cars went to auction or whatever the company did with them, but in this case another sales guy from the company (he knew the guy) bought the car as a family car and basically drove it for many yrs and it was handed down to the kid. Until it basically rusted out. At sales meetings the guy who bought the car would tell him how great it was, been real reliable. He never told the guy about his experiment. His buddy had asked what kind of oil he had been using when he first bought the car, but my buddy doesn't know what oil he used after that.

Obviously that's not something I would do on my car, but yeah it was interesting to see how it worked in that case.

Even though it's synthetic, if I were planning to keep a truck for a long time, I'd probably change the trans fluid around the 80-ish mark. If it's mostly highway miles, then maybe a little longer. Just to be safe and try to coax more out of a tranny.
As a Tech. Rep. for a large company we purchased Impalas from 1977-1979, '77 & '78 exclusively. In two years the THM200 transmission in mine was replaced three times. Out of the eighteen Impalas in my branch office, only three made it to turn-in time without at least one tranny replacement.

Regards,
Dusty
2019 Ram 1500 Billet Silver Laramie Quad Cab 2WD, 5.7 Hemi, 8HP75, 3.21 axle, 33-gallon fuel tank, 18” wheels. Build Date: 3 June 2018. Now at 102583 miles.
 

Dusty

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For those interested, I asked him about the ZF lifetime, and he responded correct, that is why the transmission is sealed. I asked what is the definition of lifetime, he said they figure the lifetime to be 150,000 miles (ah, so lifetime has a limit). I asked what about those that tow the majority of the time in the heat of Arizona or the cold of Alaska, he said they ran extensive tests well outside of the limits of the average driver at both the Arizona proving grounds as well as the Northern Michigan proving grounds with no issues. He also reminded me the ZF8 speed used in Chrysler vehicles is made by ZF (in Germany) and by Chrysler under license.

Then I asked how many transmission failures did he see. He said his group would only see/hear about transmission failures that occurred under the new vehicle warranty (three-year 60,000 or 100,000 and not Maxcare) and if the failure was undetermined then they would get it for a forensics study. He did not recall one failure pointing at the lubricity or other fault of the fluid.

I sometimes referenced "he" and "they" but I'm really referencing the powertrain group, driveline. For what it is worth.
First, thank you for inquiring about this topic with your son who works for ZF.

Most people in this thread have better than average knowledge about things automotive, and understand the impacts of lubrication. What is a fact is that lubricants, especially those designed for automotive use, have use limits. Oils and hydraulic fluids do get contaminated reducing the effects for which they were selected.

In the case of transmissions, typical ATFs are susceptible to solids and moisture contamination, the latter especially detrimental to the hydraulic properties. ATFs have come a long way since the invention of the automatic transmission. Early Buicks use motor oil and required fluid changes at every engine oil change.

The transmission environment is constantly shedding clutch material and other debris. I don't think the ZF design, although reputed to be of a very high durability and efficiency, is going to escape this. ZF has developed a design that greatly reduces the chance of moisture contamination by sealing the environment off from the internals which is why the fill procedure is so critical. Overfilling could cause seal failures from too much internal pressure (under filling could cause aeration).

So the question really is, what is the definition of "lifetime." We know that one consumer magazine which rates cars has been primarily responsible for convincing people that less required maintenance is a good thing, hence auto manufacturers have extended OCIs and other intervals. Your son also indicates that there is a 150,000 mile practical limit.

In light of your son's comment, the vehicle manufacturers 100,000 mile fluid change listed in my owners manual does not seem unreasonable. Since we know some people seriously abuse or neglect things, ZF may recommend something shorter, if nothing else to protect their reputation.

Regards,
Dusty
2019 Ram 1500 Billet Silver Laramie Quad Cab 2WD, 5.7 Hemi, 8HP75, 3.21 axle, 33-gallon fuel tank, 18” wheels. Build Date: 3 June 2018. Now at 102583 miles.
 

Wild one

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First, thank you for inquiring about this topic with your son who works for ZF.

Most people in this thread have better than average knowledge about things automotive, and understand the impacts of lubrication. What is a fact is that lubricants, especially those designed for automotive use, have use limits. Oils and hydraulic fluids do get contaminated reducing the effects for which they were selected.

In the case of transmissions, typical ATFs are susceptible to solids and moisture contamination, the latter especially detrimental to the hydraulic properties. ATFs have come a long way since the invention of the automatic transmission. Early Buicks use motor oil and required fluid changes at every engine oil change.

The transmission environment is constantly shedding clutch material and other debris. I don't think the ZF design, although reputed to be of a very high durability and efficiency, is going to escape this. ZF has developed a design that greatly reduces the chance of moisture contamination by sealing the environment off from the internals which is why the fill procedure is so critical. Overfilling could cause seal failures from too much internal pressure (under filling could cause aeration).

So the question really is, what is the definition of "lifetime." We know that one consumer magazine which rates cars has been primarily responsible for convincing people that less required maintenance is a good thing, hence auto manufacturers have extended OCIs and other intervals. Your son also indicates that there is a 150,000 mile practical limit.

In light of your son's comment, the vehicle manufacturers 100,000 mile fluid change listed in my owners manual does not seem unreasonable. Since we know some people seriously abuse or neglect things, ZF may recommend something shorter, if nothing else to protect their reputation.

Regards,
Dusty
2019 Ram 1500 Billet Silver Laramie Quad Cab 2WD, 5.7 Hemi, 8HP75, 3.21 axle, 33-gallon fuel tank, 18” wheels. Build Date: 3 June 2018. Now at 102583 miles.
The ZF isn't sealed as per say,it is still vented to the atmosphere,same as every other transmission,and susceptible to atmosphere moisture intrusion when it cools off.If it was literally sealed,it would blow seals right/left and center
 

js12278

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So, when we do the fluid/filter service we level the pan rail on the transmission, not the truck itself, correct?
Any video online regarding the service of the 8hp in any passenger car shows a vehicle level on the lift and the transmission is level. Any I've seen of a Ram 8hp being serviced all four types on the ground or jacked rear tires slightly of the ground. One I watched the guy listened the transmission mount and leveled that way (made no sense to me since you've got to run the service procedure), and a few just put in what they felt was enough fluid, drive around and rechecked level later.
I'll jack up the truck until the pan rail is level and temperature within specs.
Just fyi, all the fluid shown, in any video that I've watched, coming out of the transmission, IMO, doesn't look too far off from the new fluid.
New it's a dark green and stinks. It's nowhere near a drastic difference from green to a black or brown. I'm approaching 91,000 on my 2018 and I'll be doing the service soon.
 

NETim

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So, when we do the fluid/filter service we level the pan rail on the transmission, not the truck itself, correct?
Any video online regarding the service of the 8hp in any passenger car shows a vehicle level on the lift and the transmission is level. Any I've seen of a Ram 8hp being serviced all four types on the ground or jacked rear tires slightly of the ground. One I watched the guy listened the transmission mount and leveled that way (made no sense to me since you've got to run the service procedure), and a few just put in what they felt was enough fluid, drive around and rechecked level later.
I'll jack up the truck until the pan rail is level and temperature within specs.
Just fyi, all the fluid shown, in any video that I've watched, coming out of the transmission, IMO, doesn't look too far off from the new fluid.
New it's a dark green and stinks. It's nowhere near a drastic difference from green to a black or brown. I'm approaching 91,000 on my 2018 and I'll be doing the service soon.
Follow the "green sheet" ZF procedure and you'll be fine. You might have to remove the 3 bolts that bolt the ZF to the crossmember and lift the tail end of the ZF to allow the pan to be removed and replaced. Some trucks need to do this. Some don't. Mine did. A bottle jack and some scrap wood was all I needed to do it.

The fluid looked okay and the truck was having no issues at all but I elected to do it simply because it was time at 91K miles.
 

Wild one

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So, when we do the fluid/filter service we level the pan rail on the transmission, not the truck itself, correct?
Any video online regarding the service of the 8hp in any passenger car shows a vehicle level on the lift and the transmission is level. Any I've seen of a Ram 8hp being serviced all four types on the ground or jacked rear tires slightly of the ground. One I watched the guy listened the transmission mount and leveled that way (made no sense to me since you've got to run the service procedure), and a few just put in what they felt was enough fluid, drive around and rechecked level later.
I'll jack up the truck until the pan rail is level and temperature within specs.
Just fyi, all the fluid shown, in any video that I've watched, coming out of the transmission, IMO, doesn't look too far off from the new fluid.
New it's a dark green and stinks. It's nowhere near a drastic difference from green to a black or brown. I'm approaching 91,000 on my 2018 and I'll be doing the service soon.
ZF says you're good with checking the fluid at 122F,but if you can check it at 110 or cooler, apparently you're better off.
 

Dusty

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The ZF isn't sealed as per say,it is still vented to the atmosphere,same as every other transmission,and susceptible to atmosphere moisture intrusion when it cools off.If it was literally sealed,it would blow seals right/left and center
Where's the vent?

Regards,
Dusty
2019 Ram 1500 Billet Silver Laramie Quad Cab 2WD, 5.7 Hemi, 8HP75, 3.21 axle, 33-gallon fuel tank, 18” wheels. Build Date: 3 June 2018. Now at 102583 miles.
 

Wild one

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Where's the vent?

Regards,
Dusty
2019 Ram 1500 Billet Silver Laramie Quad Cab 2WD, 5.7 Hemi, 8HP75, 3.21 axle, 33-gallon fuel tank, 18” wheels. Build Date: 3 June 2018. Now at 102583 miles.
Top of the transmission,same place most automatics have it,lol. Think about it,if it was totally sealed it'd blow out seals as soon as it got hot,so it has to vent the air /fluid expansion somewhere,and consequently when the transmission cools off,it has to suck air back inside itself to compensate for contraction. This is a BMW ZF,but i just did a quick search,and this one shows the vent they have,look for the little blue plastic piece on the top of the transmission,that's the vent.


Not sure if this picture will work,but if it does,it shows the vent a bit better. Clic on the first pic,and you'll seen the blue plastic vent

 
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js12278

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Follow the "green sheet" ZF procedure and you'll be fine. You might have to remove the 3 bolts that bolt the ZF to the crossmember and lift the tail end of the ZF to allow the pan to be removed and replaced. Some trucks need to do this. Some don't. Mine did. A bottle jack and some scrap wood was all I needed to do it.

The fluid looked okay and the truck was having no issues at all but I elected to do it simply because it was time at 91K miles.
A video I watched the guy mentioned he had to get the rear axle up 21” to make his pan level, that’s full extension on my floor Jack. Tough call for me to roll under confidently AND run the full green sheet. I’ll likely lift the tires off until free spinning. Then I’ll free the mount, fill as required, reattach mount, run through the gears, then lift the box again and check level. I was a builder/installer in a transmission shop back in the 80s, I’d take it personal like if I fail at this
Appreciate your input.
 
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