Potential Issues With The JF506E Transmission You Should Keep An Eye Out For

Posted by on Monday, August 26th, 2013

The JF506E is a 5 speed automatic transmission made by Jatco. It was used in a number of different makes and models, including the VW Gold and Sharan, MG Rover, Ford Mondeo, Land Rover Freelander, Mazda MPV and the Jaguar X-Type. This transmission is considered to be a medium/large unit. Jatco is actually a spinoff off from Nissan.

While Jatco generally make good products, there are a few things you should look out for, as is the case with all automatic transmissions. Here is what to look for.

This is the JF506E transmission


All automatic transmissions are susceptible to overheating. In fact, overheating is an automatic transmission’s number one enemy and the JF506 is no exception. These transmissions are designed to run at a maximum temperature of 200 degrees. For every 20 degrees you go above this temperature, you risk cutting the life expectancy of the transmission by a factor of two. To better understand the affect excessive temperatures have on the life of your transmission, at 240 degrees the life span is reduced to ¼ and by 260 it drops down to 1/8th.

Heat will also destroy the transmission fluid. At temperatures as low as 240 degrees, the organic oil based fluids can start to turn to varnish. At that point it’s only a matter of time before the transmission totally fails. To help keep the temperature of your transmission under control, consider adding an aftermarket transmission cooler to your vehicle.

An internal diagram of the JF506E transmission


Another problem that is common with late model automatic transmissions has to do with the transmission’s internal electrical components, mainly the solenoids. There are five solenoids in the JF506E, four of which are used to control the shifting of the transmission, and the fifth one controls the lockup clutch.

The solenoids found in an automatic transmission are nothing more than fancy electrical/mechanical magnets. They consist of a long coil of fine wire that when energized, create a strong magnetic field. This in turn moves a plunger attached to a valve in the valve body.  The coil of wire can fail by breaking (usually caused by excessive vibration) or by melting and internally shorting out (caused by excessive transmission temperatures). Checking the condition of a solenoid is fairly simply. Attach an ohm meter to the two leads coming off the solenoid. A properly functioning solenoid should return a reading of between 20 and 30 ohms. Anything outside the range may indicate a problem with the transmission.

The JF506E transmission has many electrical solenoids


Sooner or later, due to high mileage or abuse, you will be faced with a decision to replace your JF506E transmission. I highly recommend doing so with a re-manufactured transmission over one that was simply rebuilt. A re-manufactured transmission will include major internal modifications and upgrades designed to make it both stronger and more durable. A rebuilt transmission will not include this feature. A re-manufactured transmission also comes with a much better warranty; three years compared to an average 90 days for a rebuilt transmission. And in the rare event that you need to contact the company that re-manufactures transmissions, they are just a quick phone call or email away!

One Response to “Potential Issues With The JF506E Transmission You Should Keep An Eye Out For”

  1. Denis Lalonde says:

    Your blog is interesting and somewhat informative, your leaving out some crucial information regarding the DYI guys mistaking the JF506-E reduction band anchor plug for the drain plug, releasing the band can be a big problem.
    This transaxle has none issues with the TOT sensor and solenoid C when cold.
    ATSG has TSB out on this unit.


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