Most of us dislike dirt in any form, and particularly when its existence can play havoc with how well our RVs drive down the road. Fragments of dirt and debris too small to see in the transmission and hydraulic systems are capable of holding a spool valve open to prevent adequate pressure from reaching the power steering gear, cooling fans, and transmission shifter. To help assure long life and peak performance of the RV transmission and hydraulic systems, follow the always-dependable process of proper fluid and filter maintenance.
The majority of parts used to create the transmission and hydraulic systems are considered a source of contamination. As they move back and forth, components can introduce dirt into the fluid through normal wear and tear. Hoses and housings that flex from ordinary stressors generate shock and pressure that cause minute metal and casting material to break loose and enter the fluid stream. Air entering the hydraulic reservoir will often contain particles of dirt or water vapor that add impurities. The system is also susceptible to tainting each time a line is cracked to service a component.
All of this might sound daunting, but filter maintenance is an effective weapon against dirt and debris. Neglecting the filter change schedule on the transmission and hydraulic systems can result in costly repair. To determine the number of filters used within the system, as well as their varying locations, you should refer to the operations manual for specific RV transmission and hydraulic system information. Don’t delay in seeking this important information. In many instances, the recommendation for changing the main filter on the transmission is after the first 5,000 miles. Most hydraulic filters for the power steering and cooling fans generally require a change annually or every 15,000 miles. Make it a practice to strictly adhere to recommended change intervals.
“Most hydraulic filters for the power steering and cooling fans generally require a change annually or every 15,000 miles.”
Replacement filter identification differs between RV models, so consult the operations manual for definitive replacement part information. Stay with the recommended micron rating on replacement filters. Micron ratings are used to determine the size of particle captured within the filter. A grain of table salt is rated at 100 microns, a human hair at 70 microns, and talcum powder at 10 microns. Manufacturer recommended replacement filters are generally rated at 10 microns. Attempting to reduce cost by using other than specified replacement filters can result in unnecessary repairs.
The transmission cooler may be an integral part of the radiator, or installed separate from the system. Inspect transmission fluid levels when the RV is parked on level ground and running at operating temperature. Depending on your model RV, fluid checks are carried out using a dipstick, or through the transmission shift pad. For model units that offer fluid level checks at the transmission keypad the RV must be stationary, on level ground, and running at operating temperature.
Loss of fluid may occur during filter change. Once the filter has been replaced, start and run the engine on level ground. When the transmission reaches operating temperature, carefully check fluid and add levels as required. Never attempt to recycle fluid captured in the drip pan. Miniscule particles of debris from the pan, including lint from the cloth used to wipe the drip pan, can infect the fluid supply and compromise proper operation of the transmission. Add only new fluid when required.
Occasionally check the fluid for proper color and odor. Refer to the transmission operation manual for recommended fluid changes. Change intervals may require more frequency when traveling in extreme heat, or while towing heavy loads.
The RV transmission arrives at the factory empty of fluid. Once installed, the component is filled. Following its construction, the chassis is parked on a level surface, the engine is engaged, and when the transmission fluid reaches operating temperature, the fluid level is carefully inspected and adjusted as necessary.
“TranSynd and Dexron III are presently the two fluids most often used in the RV transmission system.”
TranSynd and Dexron III are presently the two fluids most often used in the RV transmission system. A small tag may be attached to the dipstick identifying the type of fluid used. Verify the specific fluid to avoid mixing brands. Blending different brands of fluid in the RV transmission system can cause filter intervals to change. If you want to switch to a different type of fluid, seek the assistance of a qualified technician who can also help you to reduce system contamination while making that change.
Protecting the transmission is one more reason why it is important to regularly weigh the RV. By keeping the front axle within the confines of the manufacturer recommended weight ratings, you will lessen the chance of excess weight overloading the steering gear and negatively affecting how the RV handles while driving.
The temperature gauge on the dash is not controlled by a solenoid. Occasional confusion may arise over whether the transmission gauge is tracking the
gears as they are used. If your RV is equipped with an analog gauge, that gauge is sensing the temperature of the converter, which is the hottest point of the transmission oil. Maximum temperature on the analog dash gauge is approximately 300 degrees.
RVs equipped with the Aladdin system rely on a more accurate digital reading. If the transmission temperature rises up to 250 degrees while the RV is climbing a long hill, for example, it can only remain that high for 15 minutes. Once the transmission temperature reaches 262 degrees, the system will log an Over Temp fault code, and in most cases, engage the Check Trans light. When this overheating occurs, the transmission will seek a lower gear to achieve higher engine RPM to increase the flow of air, water and oil that will help to cool the
transmission.
Once you understand the basic needs of the transmission and hydraulic systems and learn the simple techniques of fluid and filter maintenance, you can enjoy the peace of mind that will come with knowing these vital systems are being properly cared for. |
