Trans. Cooler Checklist (Universal)
Posted by Patrick Muschamp on 09 19 2014 11:31 AM

This article is to explain the process the customer will need to go through in order to determine which transmission cooler is best for their vehicle. 


A transmission cooler is commonly found on automatic vehicles and most all trucks (automatic or manual). There are two different types of transmission coolers; internal and external.  The Mishimoto Universal Transmission Coolers are external coolers.

Internal - this type of transmission cooler is embedded within the end tank of the radiator. The customer will see two lines running to one side of the radiator.  These are the feed and return lines going to and from the transmission. Most all Mishimoto Universal Transmission Coolers will be an upgrade when compared to an internal cooler.  This is primarily due to the fact that an internal transmission cooler is surrounded by hot coolant at all times. (See attachment #1)

External - this type of transmission cooler is usually mounted in front of the radiator with lines routed around the radiator. This is mounted up front as the cooler needs direct airflow to operate properly. Any customer planning on mounting the cooler(s) remotely must use fans to simulate airflow. (See attachment #2 and #3)


Step 1 - Locate the OEM transmission cooler.

Note: Customers who have an internal cooler will not be able to measure the stock cooler.  As mentioned above, most any Mishimoto Universal Transmission Cooler will be an upgrade when compared to an OEM internal transmission cooler.

a. Once located, take measurements of the cooler (length/width/depth)

b. Obtain the hose/line diameter size.  The customer will need either the outer diameter of the fitting on the cooler or the inner diameter of the hose connected to the cooler.


Step 2 - Determine which Mishimoto Universal Transmission Cooler is best for your application.

a. Compare the sizes listed within the Technical Specifications to the measurements you recorded in Step 1a. As a general rule, converting to a smaller cooler may cause cooling issues with your transmission and can potentially damage your transmission. (See attachment #4 and #5)

b. Compare the hose/line diameter sizes listed within the Technical Specifications to the measurements you recorded in Step 1b. Using a cooler with much larger or smaller lines compared to stock can create transmission problems. For example, if a customer has 1/2" lines and then steps down to 1/4" lines, the customer runs the potential of not supplying the transmission with enough oil. Additionally, if the customer converts to 1/4" to 1/2" lines, there will be a decrease in pressure as the system is not set up to move enough fluid to maintain proper pressure due to the larger lines. Both situations can cause damage to a transmission.


*For customers remote mounting transmission cooler(s):

 1. As mentioned above, fans must be used if the customer is mounting the transmission cooler where it will not receive direct airflow. Mishimoto part number MMOC-U comes with a fan attached to it. If the customer is running a different Mishimoto Universal Transmission Cooler, a fan can be purchased separately here.  Mishimoto suggests using a Mishimoto Universal Fan Mounting Kit to install the fan onto the cooler.

2. Customers can also purchase the Mishimoto Adjustable Fan Controller Kit to help control when the fans turn on and off based on the transmission oil temperature.

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