ZF Transmission question - temps

[HEMIMANN]

Way too hot for transmission oil. It's oil - not a magic "fluid" like they want us to believe. I worked for Mobil Oil, I know what ATF is.

Ideal is 160F or less for transmission and oil longevity. Remember, this is BULK oil sump temp - not instantaneous temp at the hottest transmission elements like clutch plates engaging.

The ONLY reason vehicle makers have upped oil temps is for miniscule EPA fuel economy gains. PERIOD.

 

[JHoward]

^^^This^^^

 

[MegaHertz]

That's definitely on the hot side for just cruising around . The transmission thermostat has been known to fail,and the only way to get a new one,is to buy the complete thermal management unit,or install one of Jesse Caulks bypasses in place of the thermostat. For $h!ts and giggles check your transmission fluid level,as very few shops do it right,and you might be down on fluid. Follow these instructions,especially the very first highlighted paragraph about leveling the transmission,you need the rear tires in the air roughly 9" to get the pan rail level,then follow the procedure and don't try any shortcuts.The colder you can do it at,the better. According to ZF the ideal checking temp is about 100 to 110,the 122 is the max temp,not the ideal temp to check the fluid level.

Ok, this might sound like a really dumb question.

But the instructions say to jack up the car, then start the engine, and then run through various gears... including #9 "accelerate slowly to 2nd gear and hold for 5 secs".

Is all this gear shifting and accelerating really supposed to be done while the vehicle is suspended on jack stands or before jacking up the vehicle?

 

[Wild one]

Ok, this might sound like a really dumb question.

But the instructions say to jack up the car, then start the engine, and then run through various gears... including #9 "accelerate slowly to 2nd gear and hold for 5 secs".

Is all this gear shifting and accelerating really supposed to be done while the vehicle is suspended on jack stands or before jacking up the vehicle?

On jackstands,it needs to shift into 2nd gear. Block the front wheels solidly,and use a good pair of 6 ton stands and leave your floorjack under the pumpkin ,and you'll be good to go. You're not under the truck to do the procedure,you should be in the drivers seat to go through the gears,where you can step on the brakes if you panic.
BTW it is a really dumb question,if you'd applied a little common sense,lol

 

[MegaHertz]

On jackstands,it needs to shift into 2nd gear. Block the front wheels solidly,and use a good pair of 6 ton stands and leave your floorjack under the pumpkin ,and you'll be good to go. You're not under the truck to do the procedure,you should be in the drivers seat to go through the gears,where you can step on the brakes if you panic.
BTW it is a really dumb question,if you'd applied a little common sense,lol

I was thinking more like one might do those steps out on the street before jacking up on stands. Like drive cycle procedures after clearing codes or something. Then putting up on jacks stands. I assume the purpose of those steps is to ensure the trans oil is good and evenly circulated to get an accurate level?

 

[EdGs]

I was thinking more like one might do those steps out on the street before jacking up on stands. Like drive cycle procedures after clearing codes or something. Then putting up on jacks stands. I assume the purpose of those steps is to ensure the trans oil is good and evenly circulated to get an accurate level?

After the drain and fill, then going through the procedure on jackstands, I took mine out for a full temp run, then let her cool completely and did another full fluid check procedure on stands again. It took a few ounces more fluid. When it cooled enough and I rechecked it, had some fluid dribbling out, so I called it good.

 

[Hookedup87]

I just had the 8 speed on my '18 Ram 1500 serviced yesterday right about at the 75,000 mile mark.

First off, I want to say a big thank you to Caulk04 for his thermal bypass kit as well as his quick reply to a message I sent him looking for the link to the install instructions. I bought the valve quite a while back and finally found my way back to the old thread, found, and messaged him. He responded almost immediately with the link , which I promptly printed out and gave to the transmission shop that did the service.

Not only does the valve work perfectly, but I also header wrapped the crossover pipe that passes directly under the transmission pan. Between those two things, I am seeing transmission temps running 40 degrees cooler than before!

Not only am I seeing a dramatic difference in the transmission temp, but I am also seeing a slight decrease in my coolant and oil temps as well. It's a win, win, win.

I plan on keeping my truck for as long as possible. I love it. So long term durability and reliability is very important to me. Pulling so much heat out of crucial fluids like this is definitely gonna help I believe.

 

[Wild one]

I was thinking more like one might do those steps out on the street before jacking up on stands. Like drive cycle procedures after clearing codes or something. Then putting up on jacks stands. I assume the purpose of those steps is to ensure the trans oil is good and evenly circulated to get an accurate level?

Not really advisable to try and drive it first,as you'll exceed the 122F checking temp by the time you get through the procedure. I jack mine up and pull the pan and let it drip overnight,then install the pan/filter / top it off with as much fluid as i can get in it,in the morning when it's cool,then start the truck and go through the procedure,that way i've done the shift into 2nd and the rest of the procedure,well before it's at the max checking temp of 122F.The instructions give you a window of 86 to 122F as the checking temps,and from what i've found out ZF likes to see the trans ideally checked at between 100 and 110.
Ed's way of doing it twice is actually a very good idea.
PPE makes a heavy duty pan that uses a replacable filter and holds another couple quarts of fluid,which is a nice option,if you plan on keeping the truck for awhile.

2014-2024 w/ZF-8 Speed Transmission Heavy-Duty Cast Aluminum Deep Transmission Pan

Transmission Pan - Heavy-Duty Cast Aluminum - 8HP70/8HP75 Features:Cast-aluminum construction Increased heat dissipation Reduced oil temperatures Increased fluid capacity Stainless steel drain plug Includes replaceable filter 1/8 NPT tempe

ppepower.com

 

[Wild one]

I was thinking more like one might do those steps out on the street before jacking up on stands. Like drive cycle procedures after clearing codes or something. Then putting up on jacks stands. I assume the purpose of those steps is to ensure the trans oil is good and evenly circulated to get an accurate level?

If you don't have a transfer pump,it's easy to build one out of a cheap 1 gallon garden sprayer.Having one will make the job easier.

DIY Homemade Fluid Transfer Pump for $13. Cheap and Easy!

Decided to try out an easier and faster way to transfer transmission fluid. Doesn't take much prep time to get it done. Finished it in less than 5 minutes.Th...

www.youtube.com

 

[JHoward]

I was thinking more like one might do those steps out on the street before jacking up on stands. Like drive cycle procedures after clearing codes or something. Then putting up on jacks stands. I assume the purpose of those steps is to ensure the trans oil is good and evenly circulated to get an accurate level?

... and according to the instructions, the tranny being between 88°-122° for an accurate fill and don't overfill.