I am doing some upgrades on a 4r44e valve body on my ranger. It has 245k and the transmission is stock and original. I am installing a sonnax zip kit. One of the concerns is the thermostat in the transmission. When the fluid gets to 150f there is a small pin that extends and that pushes a valve to direct oil flow through the oil cooler. I tested the thermostat in a cup of water with a thermometer and it did start to extend the pin at 150 with the pin reaching full extension around 170f. There are concerns floating around the internet stating the thermostat can fail and that causes the fluid to keep recirculating and can overheat and ruin the fluid and in turn the transmission. It can also stick half way causing issues. Now there are two ways to rectify this issue. One is with a small metal piece in a superior 5r55e kit that sits in front of the thermostat and keeps the valve pushed open allowing full cooler flow. The other option is to take the spring from behind the thermostat and moving it to the front of the thermostat in turn also moving the valve into its full flow position from the spring pressure. The spring flip flop is free but the superior kit also includes a seal for the reverse servo which is a double lip seal instead in just the standard o ring which is supposed to help with fluid leakage past the o ring when the reverse servo is applied. I am not opposed to keeping the thermostat and keeping it stock as i do like the idea of the fluid having a minimum temperature to help with moisture control especially in the winter. The truck has a factory stacked plate trans cooler and i do tow up to 5000lbs occasionally with it. What are your thoughts on me keeping the thermostat vs bypassing the thermostat?
Looking for advice on 4r44e thermostat
- Thread starter joegreen
- Start date
Transmissions have their own heat source, The fluid coupling of the torque converter. Most vehicles delay converter clutch apply until the transmission reaches a certain temperature. For emissions/fuel economy reasons manufacturers want the converter clutch in play as soon as possible.
Millions of automatic transmission were produced before thermal bypasses.
Millions of automatic transmission were produced before thermal bypasses.
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