The Top DSM Community on the Web

For 1990-1999 Mitsubishi Eclipse, Eagle Talon, Plymouth Laser, and Galant VR-4 Owners. Log in to remove most ads.

Please Support STM Tuned
Please Support Morrison Fabrication

Extending Automatic Transmission Life (Long)

This site may earn a commission from merchant
affiliate links, including eBay, Amazon, and others.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

transdude

20+ Year Contributor
526
56
Jan 17, 2003
Hawthorne, New_Jersey
I've posted this elsewhere, but perhaps you guys will find it relevant as well.

Here are some suggestions that will help to extend the life and increase the durability of your automatic transmission.

These things are especially important for severe duty applications, but are also applicable to almost all vehicles.

1) Check your fluid level regularly- although fairly obvious, many people neglect to do this- or do this wrong.

Consult the vehicle's owner's manual if you are unsure as to how to do this correctly, as it can vary between different vehicles.

If you need to add fluid, it is always indicative of a leak. Unlike motor oil, your transmission fluid level can only go down if you are losing it somehow.

2) Service your transmission regularly- transmission fluid breaks down in the same way that motor oil does, but this is a step in preventive maintenance that is often ignored.

I've rebuilt countless transmissions over the years that clearly were never properly maintained- many of them had never had a single fluid and filter change.

Many manufacturers have different recommendations on the service intervals, but I recommend that this be done once a year or every 15- 20,000 miles.

3) Install an external transmission cooler- you've all heard the cliché that heat is the number one cause of transmission failure, well it's true.

A reduction of 40 degrees in your transmission fluid temperature can double the life of the unit.

When shopping for a cooler, a stacked plate design is far superior to a "tube and fin" type. If you're going to go through the trouble of installing one, you may as well put on the best kind.

On this same subject, it is also always a good idea to insure that your vehicle's cooling system is in optimum condition- most automatics utilize a fluid to antifreeze heat exchanger that is built into the radiator.

4) Install a transmission temperature gauge- with a gauge you will be able to tell when your trans is getting hot before it's too late.

5) Add a friction modifier- there are a few excellent products that can be added to your automatic trans that will significantly increase the life of the transmission. I recommend the products that are made by LubeGard.

On the same subject, avoid at all costs the auto parts store "mechanic in a can" and "stop leak" type products- they are mostly seal swelling agents and will usually harm the trans rather than help it.

6) Install an in line cooler filter- most automatics have some type of filter, however, there is always room for improvement.

Factory filters vary in effectiveness; many transmissions use something that isn't much better than pouring the fluid through a screen door.

The idea is to eliminate contaminants such as small metal particles and loose debris as effectively as possible.

In line filters are inexpensive, easy to install, and are highly effective in removing damaging contaminants from the transmission fluid.

I recommend the ones made by Magnafine and Filtran- in addition to their filter element, both of these products have a bypass valve in case they become clogged and also an internal magnet to further aid in trapping ferrous debris.

7) Use a synthetic based fluid- automatic transmission fluid serves many functions. It provides cooling and lubrication, it is the hydraulic fluid that applies the clutches and bands, and it even "drives" the car through the fluidic coupling that occurs in the torque converter.

It stands to reason that a synthetic fluid is much less susceptible to breakdown, a better lubricant, reduces friction and also has the capability of reducing operating temperatures.

More importantly, in cases of extreme cold and extreme heat, fluid made with a synthetic base stock is much more stable from a viscosity standpoint. If you don't believe me, try to pour "dinosaur" oil out of a container at -10 Fahrenheit- it's not exactly going to serve very well as a lubricant when it's the consistency of Jell-O.

8) Check transmission problems promptly- most transmission problems start out small and will get worse over time. Often times, major repairs can be avoided by taking care of a problem early on.

If you see a warning light on the dash, see a few drops of fluid in the driveway or even just have a feeling that something isn't quite right, there is no better time than the present to get it checked out.

9) Install a shift kit or modified valve body- while normally thought of as a "high performance" modification, almost any vehicle will benefit from shortening the shift time, reducing overlap and "cleaning up" the shift quality. This in turn reduces heat and also reduces wear on the clutches and bands.

Many of these modifications also address certain factory design shortcomings and eliminate common drivability complaints.

Most of the better engineered products have shift quality settings that are adjustable to achieve a result that is appropriate for the intended usage. The person with an 11 second rocket will have different needs than the person who occasionally tows a trailer with his SUV.

I hope that I didn't bore anyone with this long post.

-John
Owner, import performance trans
 
what is the maximum safe trans fluid temperature that a/t owners should shoot for?
 
I've searched but can't find any faq's on the subject..

Thanks.
 
Originally posted by unior
what is the maximum safe trans fluid temperature that a/t owners should shoot for?

160-200 degrees is safe.

-John
 
Originally posted by Morel
I've searched but can't find any faq's on the subject..

Thanks.

You can remove the cooler return line, have someone start the car and run it in neutral as you keep adding fluid until the ATF coming out of the return line looks clean.

-John
 
It should pump out about a gallon per minute in neutral.

-John
 
What happens if the fluid is overfilled and it goes un-noticed for several months?

This happened to me as the person who changed my filter and fluid overfilled and I didn't know until I started having transmission problems. I don't know if the two are connected, but I was told that overfilling can cause damage. Just wondering if this is true.
 
DSMchick said:
What happens if the fluid is overfilled and it goes un-noticed for several months?

This happened to me as the person who changed my filter and fluid overfilled and I didn't know until I started having transmission problems. I don't know if the two are connected, but I was told that overfilling can cause damage. Just wondering if this is true.

A trans that is substantially overfilled will usually "puke" out of the breather when it gets hot. After that, the level kind of "corrects itself" :)

What you need to look out for when you check the fluid on a DSM is to make sure that it is running and in neutral, if it gets checked in park, it will give a false reading that will look like it is about 2 quarts too high.

-John
 
Support Vendors who Support the DSM Community
Boosted Fabrication ECM Tuning ExtremePSI Fuel Injector Clinic Innovation Products Jacks Transmissions JNZ Tuning Kiggly Racing Morrison Fabrications MyMitsubishiStore.com RixRacing RockAuto RTM Racing STM Tuned

Latest posts

Build Thread Updates

Vendor Updates

Latest Classifieds

Back
Top