Technical Help Bulletins

We're here to help so here's some very useful and important information

Transmission Cooler Flushing

Transmission oil coolers must be properly flushed using a power flush machine.  These power flushers properly flush and pulse transmission coolers and lines to remove metal, dirty oil, and material from a failed transmission prior to installing a remanufactured transmission.

Using solvent and air is not the proper procedure for flushing out transmission coolers and lines.  There are store bought products such as Trans Flush that aid you in flushing your transmission cooler and lines, but does not produce the same results as using a power flusher.

Problems Associated with Improper Flushing

Hydraulic Transmission Types - Improperly flushed transmission cooler and lines will leave behind debris which can cause sticky governors, wrong gear starts, stuck valves, shift issues, and premature failures in your newly installed remanufactured transmission.

Electronic Transmission Types - Improperly flushed transmission cooler and lines will leave behind debris which can wreak havoc in electrical controlled transmissions.  Electrical solenoids and valve bodies when energized under normal operation act like electro magnets.  These "Electro-magnets" will tend to pickup any metal or debris left in the transmission cooler and/or oil.  This can cause malfunctioning in valve bodies and solenoids causing wrong gear starts, shift issues, low line pressure, skipped shifts and late shifts.

Engine Stalling - Many times a plugged or restricted transmission cooler will cause the engine to "Stall" when put into reverse.  This is caused from a lack of oil feed to the transmission causing the lock-up torque converter to engage or restrict flow.

Mandatory Transmission Cooler Replacement

Many vehicles after transmission failure require that the transmission cooler/radiator be replaced in order to reduce repeated failures.  This is mandated by the factory in many service bulletins as well as by ATR.  The reason is this...Many of these vehicles have a "fin type" transmission cooler in the radiator and after a major transmission failure, the debris from the failure clogs these fins and will restrict flow causing damage to a transmission quickly.

This can be avoided in one of two ways:

  • Replace the radiator in the vehicle (Trans cooler in radiator), which is very costly.
  • Use an External By Pass Cooler.

An inexpensive way is to completely bypass the trans-cooler in the radiator (not running through the radiator cooler at all), and installing a Heavy-Duty external transmission cooler.  These are easy to find at any Auto Parts Supply House.  ATR recommends a large transmission cooler that fits your vehicle's front radiator/condenser space.

The following is a list of Transmissions that requires a mandatory transmission cooler replacement:

  • Ford E4OD and 4R100 Series
  • Chrysler - All 500's, 518, 618, 45RFE and 47RE Series
  • Jatco (Isuzu, Nissan, Mitsubishi) JR403 Medium Series Trucks
  • Aisin 450-43LE (Isuzu, GM Tiltmaster, Nissan, Mitsubishi) Medium Series Trucks

Inline Filters - All Light-Duty transmissions come with Inline Filters.  This helps prevent any metal from returning to the cooler.

Technical Service Information for Aisin 450-43LE

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