In this Blauparts Ram tech tip article, we'll address a common question among Ram truck owners, particularly those with the Ram ZF 8-speed transmission: What is the acceptable transmission temperature when towing, and what is the optimal or safe operating temperature? Using a 2019 Ram 1500 with the 5.7L V8 Hemi and Sport long wheelbase as our test vehicle, we provide insights that are also applicable to Ram 2500 and 3500 models equipped with the ZF 8-speed transmission.
Post Contents [hide]
- Ram Towing Transmission Temperature
- Ram Highway Towing Temperatures
- Ram Stop-and-Go Towing Temperatures
- Supplement Findings: High Ram Engine Temperature with Stop-and-Go Towing
Ram Towing Transmission Temperature
What is the proper transmission temperature when towing with a Ram 1500 equipped with a ZF 8-speed transmission? From time to time, we get this question from customers who are concerned about whether their Ram 1500 transmission temperature is too high or safe when towing.
We also receive questions like, will using a fully synthetic transmission fluid lower the transmission temperature when towing? For all practical purposes, no. This is mainly due to how the Thermostat & Related Transmission Temperature Monitoring System is set up as described below. It's also important to consider the information under the title heading The Importance of Changing Ram 1500 Transmission Fluid (ATF) More Frequently When Towing.
Ram Thermostat & Related Transmission Temperature Monitoring Systems
The ZF 8HP transmission is equipped with a thermostatically operated ATF cooler typically mounted on the driver’s side of the transmission. The cooler has a thermostatic bypass value that controls transmission fluid temperature.
When the engine is cold the transmission fluid bypasses the transmission fluid cooler. This process is meant to help the transmission and fluid reach the operating temperature faster than if the ATF ran through the cooler when cold.
The bypass valve thermostat is supposed to slowly open at around approximately 165° F and be fully opened around 200° F. Since the transmission cooler uses and circulates engine coolant, and normal engine coolant temperatures are around 200° F, it would be normal for the transmission temperatures to be very similar to the engine temperatures under normal conditions. Comments from Ram 1500 owners in online forums also indicate the normal transmission temperatures should be around 200° F.
Images Description Transmissions driver side left just above the shift cable. The transmission heat exchanger and manifold is an oil or ATF to coolant heat exchanger that includes a thermal bypass valve (thermostat is the small black circle area) to help regulate or optimize the transmission operating temperature. Coolant is used to heat the transmission to get it up to an ideal operating temperature. The ATF flows through the cooler manifold (back side between heat exchanger and transmission) where heat can be transferred to the transmission fluid. The built-in thermostat or thermal bypass valve is calibrated for 82° C (180° F).
Above: The transmission driver side left just above the shift cable pictures the transmission heat exchanger and coolant manifold. Heat exchanger outside and thermostat coolant manifold mounted between heat exchanger and transmission.
Below: Zoomed-up picture of the built-in thermostat or thermal bypass valve is the small black circle area.
To help troubleshoot and address this FAQ we decided to take our own Ram 1500 to see the operating temperatures of the transmission with a fully loaded trailer. In the Wisconsin summer heat, we set out to see what transmission temperatures our Ram 1500 transmission would operate at when towing a loaded trailer.
Our tow test vehicle was a 2019 Ram 1500 Sport long wheelbase with the 5.7L V8 Hemi and the ZF 8-speed transmission. We recently performed and installed our BLAU® Transmission Fluid and Filter Change Kit for the ZF 8HP type transmission. We towed a 14’ utility dump trailer with a Kioti compact tractor at a combined weight of 8,200 lbs. We subjected the Ram truck to a number of different driving conditions, including highway towing and stop-and-go towing.
- First, the vehicle was brought up to temperature. Sitting stationary with the engine idling the operating coolant temperature was around 195° F - 200° F and the transmission temperature stayed consistent at around 170° F.
Starting Ram towing test weather conditions:
- Humidity: 90%
- Wind Speed: S 18 G 25 mph
- Barometer: 29.82 in (1009.6 mb)
- Dewpoint: 69°F (21°C)
- Air Temperature: 75° F - 81° F
Ram Highway Towing Temperatures
We then switched the Ram 1500 transmission into tow-haul mode, which works great when towing down the highway. The Ram 1500 Hemi with 8-speed transmission did a good job upshifting at the right RPM, staying in the correct gear to provide the best power for towing, proper engine braking during downshifting, and when decelerating and coming to a stop at the end of the off ramps.
Towing 8,200 lbs for around 40 miles, the Ram 1500 was easily able to maintain 70 mph on the highway in every situation. We even had several miles of sustained uphill towing pulls accompanied by 20 mph headwinds. The power and torque of the Ram 5.7L Hemi when towing are impressive. It even felt like it had power to spare.
- Traveling on the highway at 70 mph in all the above-mentioned conditions, the engine coolant temp fluctuated any ware from around 195° F - 199° F with the towing transmission temperature rising to around 190° F - 193° F.
Ram Stop-and-Go Towing Temperatures
After our highway testing, we then subjected the Ram transmission to repeated stop-and-go driving while towing 8200 lbs. This testing consisted of starting in 1st gear and accelerating up through the gears, then decelerate letting the transmission downshift to a stop. We repeated this sequence for about 25 miles and observed the temperatures.
- During the stop-and-go Ram towing the engine coolant temperature rose to about 195° F - 199° F most of the time. After several repeated aggressive towing acceleration runs through the gears, the engine temperature rose to around 201° F with the auxiliary radiator cooling fans engaging just shy of 201° F. The transmission temps were always just slightly lower than the engine coolant temperature, usually around 194° F - 199° F when towing in stop-and-go traffic.
Supplement Findings: High Ram Engine Temperature with Stop-and-Go Towing
During the above stop-and-go towing test we noticed that the engine’s oil temp reached 237° F after several of the stop-and-go sequences, as described above. Engines with oil temps running at 230° F or higher NEED to use very high-quality premium full synthetic PAO-based engine oils, to withstand high oil temperatures, avoid thermal breakdown, and minimize shear. It is our opinion and repair maintenance experience, that if you’re just running a low-quality everyday normal engine oil and operating in this higher temperature range while towing, you potentially affect engine wear and the creation of engine reliability issues (Associated with premature camshaft and lifter tappet wear, commonly referred to as the Hemi tick).
We offer a full line of high-quality fully synthetic engine oils for Ram 1500 models. Our Eurol and Ravenol oils are made to handle high-temperature running conditions. Learn more about our oil change kits in the provided link.
Ram Transmission Fluid Change Intervals
- Some vehicle and transmission manufacturers commonly use marketing statements, "lifetime transmission fluid" and "sealed for life transmission" in their owner or service manuals. However, there appears to be published information by the transmission manufacturer ZF (who makes the popular 8HP series 8-speed transmissions for many vehicle manufacturers) recommending the transmission fluid be changed every 60,000 - 50,000 miles or eight years, whichever occurs first.
- Ram 1500 models that experience more aggressive driving styles or are used in the commercial delivery industry and contractor trades are typically subjected to heavy city traffic or trailer pulling that generates extreme heat in the transmission. Owners that subject their vehicles to these types of severe driving conditions should consider replacing the transmission fluid and filter more frequently, such as every 40,000 miles.
The Importance of Changing Ram 1500 Transmission Fluid (ATF) More Frequently When Towing
The Ram 1500 automatic transmissions have hundreds of moving components, such as gear sets, drive sprockets, needle bearings, ball bearings, pressure pumps, clutch packs, servo pistons, valve body components, and seals. These internal components mesh or engage with one another, causing friction, and begin to wear and create fine metallic particles that contaminate your Ram 1500 automatic transmission fluid over time. This is also rapidly increased when towing as many of these transmission components are working extra hard or being used at their limits. Your Ram 1500 automatic transmission fluid (ATF) and filament transmission filter eventually become contaminated with these particles. These metallic particles can cause wear on these internal transmission components leading to inefficiencies in the transmission and long-term reliability issues or even transmission damage and failures if not serviced.
FAQ: Can Fully Synthetic Transmission Fluid Lower the Transmission Temperature? Or Make it Run Cooler?
Some incorrectly assume that simply changing their transmission fluid to a fully synthetic will lower the transmission temperature when towing. For all practical purposes, this is not the case. Due to the Ram transmission design, the transmission thermostat system dictates the transmission fluid operating temperature. See the Thermostat & Related Transmission Temperature Monitoring Systems heading above, as well as the following important information to consider:
There are benefits when using a fully synthetic ATF to ensure optimal transmission functions. Typically, fully synthetic lubricants have higher shear loads and can resist more frequent thermal breakdown situations, as well as, improvements or resistance in thermal breakdown over time and use. However, there are many circumstances to consider as listed below on why to change your transmission fluid, no matter how high quality it is.
FAQ: Can Old Transmission Fluid Affect Your Transmission Temperature? or Cause Transmission Issues?
Long-term transmission use with contaminated fluid that includes these worn fine metal particulates suspended in the fluid will cause a non-neutral PH level resulting in an acidic or corrosive transmission fluid. Over time this acidic and corrosive condition in the transmission fluid system can accelerate wear on key internal mechanical components, especially tight tolerance mechatronic valve body units, seals, O-rings, plastics, and soft metals. This can result in poor transmission operation such as delayed shift points, rough or jamming shifts, transmission leaks, and slipping.
Through everyday transmission use and thousands of transmission operation shifting cycles, the essential additives, and base oils in the transmission fluid will also become depleted, break down, and wear out. When towing your transmission fluid also experiences higher fluid temperatures resulting in accelerated fluid breaking down. Degraded oxidized transmission fluids result in a loss of viscosity and lubrication between key transmission components causing wear. This can commonly be identified by a burning smell and an excessively dirty black, brown fluid color.
As part of your vehicle's regular maintenance, you should change the transmission fluid and filter, replenishing the transmission with fresh transmission fluid and its key lubricating properties. This is especially important when the truck is used for towing or hauling heavy loads. 
Suppose a Ram 1500 transmission has had poor service and has worn out the transmission fluid. In that case, it will typically be noticed by poor transmission operation with symptoms such as premature late shift points, rough or jamming shifts, and slipping. If you have seen a new transmission fluid, it's nearly clear in color when compared to the dark color of an old worn-out transmission fluid. You most likely will agree that it is logical that changing your Ram 1500 automatic transmission fluid and filter on a regularly scheduled interval is necessary for long-term transmission reliability and consistent performance. Suppose you are experiencing these transmission shifting issues. In that case, we recommend changing your automatic transmission fluid and filter as a first step in trying to resolve any problems dealing with transmission operation.
Why Consider Multiple Transmission Fluid Changes in Short Succession When Towing
The total dry transmission fluid fill capacity for the RAM 8-speed transmission is around 8.7 quarts or 8.5 liters. However, due to the transmission design, only about 5.8 quarts or 5.5 liters will drain from the transmission when removing the transmission pan and changing the transmission filter. Around 3.0 liters will be remaining in the transmission torque converter and other related transmission components which can be difficult to service. Our current understanding is that a reasonable way to flush the remaining old fluid out of the torque converter and other components is by performing multiple fluid changes in short succession. If you desire to perform this thorough ATF fluid change strategy, we recommend adding 4 - 5 liters of Ram 8-speed type ATF to your cart for each additional flush you plan to perform.
Blauparts highly suggests using this strategy if the transmission is used regularly for pulling heavy loads, used for commercial fleet, or has neglected maintenance history to restore the fluid to its full lubricating performance levels and remove as much of the contaminated or deteriorated fluid as possible.
Correct Ram Transmission Fluid Type
The importance of using the correct Ram transmission fluid type can't be understated. To ensure proper transmission performance and longevity, we always recommend using a transmission fluid that specifically states use for 8-speed Ram automatic transmissions. Some fluids display performance levels for the 8-speed Ram transmission but use general formulations that are multi-vehicle transmission types but are not specifically for the Ram 8-speed automatic transmission application. Some ATFs claim performance levels for Ram but use general formulations that are multi-vehicle transmission types of ATF fluid and are not specifically for the Ram 8-speed automatic transmission application.
The 8-speed Ram automatic transmissions require a specific fluid designed and formulated for ZF transmissions, often referred to as ZF Lifeguardfluid8 fluid. The correct Ram transmission fluid can be identified as Mopar ZF 8&9 Speed ATF or equivalent, also known by Chrysler Mopar 68218925AA, 68218925AB, 68339073AA, 668157995AA, or 68157995AB transmission fluid part numbers.
Our 6700 Eurol transmission fluids and 8HP Ravenol transmission fluids are formulated with the Ram 8-speed transmission applications in mind. These fluids ensure the perfect function of the Ram 8-speed transmission and maximize wear protection, reliability, and performance.
Ram Automatic Transmission Fluid 8 Speed Fitments
- 2013 - 2019 Ram 1500 3.6L V6 with 8 Speed Automatic Transmission 845RFE aka 8HP45
- 2020 - 2024 Ram 1500 3.6L V6 with 8 Speed Automatic Transmission 850RE aka 8HP50
- 2014 - 2018 Ram 1500 3.0 V6 Diesel with 8 Speed Automatic Transmission 8HP70
- 2020 - 2023 Ram 1500 3.0 V6 Diesel with 8 Speed Automatic Transmission 8HP75
- 2013 - 2018 Ram 1500 5.7 V8 with 8 Speed Automatic Transmission 8HP70
- 2019 - 2024 Ram 1500 5.7 V8 with 8 Speed Automatic Transmission 8HP75
- 2021 - 2023 Ram 1500 TRX 6.4 V8 with 8 Speed Automatic Transmission 8HP95
- 2019 - 2023 Ram 3500 transmission fluid used in 6.4 Litre 16 Valve V8 Models
- 2019 - 2023 Ram 2500 transmission fluid used in 6.4 Litre 16 Valve V8 Models
Why Choose Blauparts for All Your Vehicle Lubrication Needs?
BLAU® transmission fluid change kits use high-quality, synthetic* transmission fluids. Our fluids are sourced from lubricant partners that employ sustainable efforts to improve the environment using a higher level of quality. This in turn can support the conservation of the environment through less transmission fluid changes and waste, optimize vehicle efficiency and performance, improve and maintain fuel economy, reduce exhaust/carbon emissions, and improve performance through reduced coefficient of friction and less driveline rolling resistance.
*For most kits, check the product description.
- Convenient BLAU® ATF change kits include the correct spec, oil quantities, and OEM quality transmission filter for your specific vehicle make and model
- ATFs that meet or exceed your vehicle manufacturer's specific transmission fluid specification requirements
- Better transmission performance, less transmission slip, improved torque, and precise shifting efficiency
- Sustainable ATFs that conserve the environment, improve fuel economy, and reduce exhaust/carbon emissions through improved transmission operation
- Higher quality ATFs allow for longer change intervals and extended service lives, conserving the Earth's resources
- Higher quality ATFs with advanced fluid technologies provide improved lubricating properties for less transmission wear and longer life
- High-performance ATF with better shear load and flow performance properties
- ATFs with better cold temperature pour points and high heat flashpoints providing protection in all conditions
- ATFs with high, stable viscosity index reduces coefficient of friction inside the transmission
- ATFs with high thermal oxidative stability with excellent cooling capacity for better transmission performance and less wear
- ATFs with lower cold temperature pour points and high heat flashpoints provide transmission wear protection in all climate conditions
- Long-life OEM ATF filters for extended fluid change intervals
See our disclaimer on the right-hand side of this page. Always consult your service manual and confirm your application's specific fluid and oil requirements. Always follow the vehicle manufacturer's recommended oil change intervals. Blauparts, RAVENOL, and Eurol are not affiliated with Fiat Chrysler Automobiles N.V (FCA), FCA US LLC, FCA Group Marketing S.p.A, Dodge, Ram, Jeep, Mopar, ZF, BorgWarner, New Venture Gear, its affiliated companies, subsidiaries, its licensors, any other vehicle, or vehicle part manufacturer. All trademarks and OE specification part numbers referenced in this product listing are displayed for identification purposes only. They are in no way intended to denote any affiliation with their corresponding owners.
