Secret to Long Automatic Transmission Service
Heat is Your Transmissions Greatest Enemy
Overheating is responsible for the majority of automatic transmission failures. Normal temperatures run about the same as the engine coolant temperature which is regulated by the thermostat to around 195 degrees F.
This brings up a very important point. A well maintained cooling system can extend the transmissions life. Part or all of the transmissions oil cooling function, depending on your vehicle, is built into the vehicles radiator. If the vehicle has an external auxiliary transmission cooler, outside of and usually in front of the radiator, it can help keep the transmission oil and engine coolant cooler.
As the temperature of the transmission fluid increases, the life of the fluid deceases very rapidly:
- 195 degree F. allows the fluid to be run for up to 50,000 miles before servicing is required
- 212 degree F. causes the fluid life to be cut in half to 25,000 miles
- 235 degree F. causes the fluid life to be cut in half again to 12,000 miles
- 255 degree F. causes the fluid life to be cut in half again to 6,250 miles
Based on these temperatures you can see that one overheat condition of the cooling system or the transmission is cause for immediate replacement of the transmission fluid.
Towing Increases the Temperature
Light to moderate load towing will try to increase the transmissions temperature but the cooler would control it under most conditions. If the outside temperature is too high, you are towing in mountainous areas or any of the three following are happening your transmission is at risk:
- Towing in overdrive when it is not recommended for your transmission will cause excess heat and probable failure of the overdrive components in the transmission.
- The extra weight of towing puts additional load on the engine and transmission which will increase the operating temperature of both. If the cooler can’t handle this extra heat the transmission fluid life is reduced as stated above.
- Towing a load over the rating of the tow vehicle, besides being unsafe, will also drive temperatures too high.
Add Extra Cooling if Towing
Installation of an auxiliary oil cooler can protect against excess heat causing premature transmission failure. Dropping the fluid temperature by 20 degrees F. will potentially double the life of the fluid. Most external coolers will drop the fluid temperature by 20 to 30 degrees F.
Service it Regularly
Most repair shops recommend servicing your automatic transmission around 30,000 to 50,000 miles for normal driving conditions which exclude towing or extreme hot, cold or dusty conditions.
Prices for a complete filter and fluid replacement normally run around $120 to $180. If you are just getting a fluid flush the price runs in the $80 to $99 range.
Some transmission repair shops do not perform flushes. They believe the best method is regular removal of the oil and filter by removing the pan on the bottom of the transmission. You should also be aware that some manufacturers, like Honda, have clearly stated not to flush their transmissions in one of their factory bulletins.
As described above the breakdown of the fluid due to heat causes it to not protect the internal moving parts of the transmission. This will greatly shorten the life of your transmission. Overhaul or major repairs run in the area of $1600 to $2600 depending on the extent of internal damage and the type of transmission.
Wayne’s Transmissions in Boise specializes in diagnosis, service and repair of automatic transmissions.
Call Wayne’s today for an appointment or consultation at (208) 322-1236
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