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mysticj

How To: Maintain an Automatic Transmission

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When it comes to automatic transmissions, the tuner world frowns down upon it. People cry about not being able to have driver's input in gear selection, it overheats, its heavy, it unrealiable, etc. While some of these statements may be true, nine out of ten people do not prep the auto when enhance the engine horsepower. Majority of automatic failing are due to lack of maintainence and lack of cooling. Most people do not have their tranny service at regular intervals, and heat kills automatic transmissions. High temperatures will cause the fluid to breakdown causing poor acceleration, slippage, blown seals, and damage the solenoid and other internal parts.

Maintainence

-Routine Fluid Exchange/Flush

Number one failure of automatic transmission is not replacing the burnt brown fluid with new clean fluid. Dirty fluid can clog solenoids, causing them to overheat and not to function properly. Get the tranny properly flush, not drain and fill as it DO NOT remove all the fluids from the transmission. You are wasting your time and money by doing so. Its good to have the transmission flush every 30K miles or half of that for those who are on the bottle or boost. There are transmission machines that will properly flush your transmission, so will use a cleaner prior to exchanging/flushing the tranny like BG. If you planning to do this in the driveway, I would use about a pint of Seaform and drive it for about 10 minutes before flushing. After the fluids been replace, now its a good time to replace the transmission filter.

-Secondary Filteration

Most automatic transmission comes with either an internal or external filters. Older Mitsu transmission have either an internal filter located in the pan or top mount screw on filters. The newer transmissions have an internal filter that cannot be replace unless its being overhaul. Either way, inline filters can add additional protection to your transmission. Simply installed it in the cooler line, just make sure that the filter provide a constant pressure before and after the filter.

-ATF

All Mitsu trannys use a Dexron II/III type fluid excepts CVT, and since most 6G-8G Galants have over 80000 miles I recommed Valvoline MaxLife ATF. Its a synthetic fluid with extra protection for vehicles over 75000 miles. Also, Valvoline Dexron VI is a full synthetic that is backward serviceable to Dexron II/III. Other synthetic ATF are Amsoil, Redline, and Mobil 1

Performance: Beginners-Intermediate

-Transmission Cooling

Most transmissions fail because of lack of cooling and the OE unit is not build for performance but rather reliable. If you want more reliablity then upgrade to a larger cooler and depending on your goals, larger is usually better. If space is a problem then running two coolers may be neccessy. For those who plan on drag racing or using an aftermarket radiator, then a fan is needed. It can be either be activate by a toggle switch in the cabin or uses of a thermo switch at a preset temperature. Speaking of temperature, now is a good time to install a trans temperature gauge. Normal operating temperature is 165 to 180F.

-Line Pressure Mod

By increasing the line pressure, it slightly increase the stall rpm of the torque converter, increase shift points, and provide quicker gear change by making the clutches/bands engage faster rather than smoothly. This quicker engagement reduce friction on the clutches, which in turn reduce heat build up.

On the valve body is an adjustable screw to increase or decrease line pressure. Counterclockwise will increase and clockwise will decrease; a full turn of the screw is +/- 5 psi. Beware that too much pressure will cost seals to blow, along with other things internally. Stock line pressure is 150 psi (8G), ~128 psi (7G)

Performance: Intermediate-Advance

-High Stall Torque Converter

Increase the stall of the converter to rev the engine into a better or sweet spot prior to launching the vehicle.

=More Coming Soon=

-Rebuild Transmission

Rebuilding the auto with new seals, upgrade bands, and kelvar clutches. Not limited to modified valvebody to futher increase line pressure.

=Coming Soon=

-ECU Reflash

Electronically control solenoid duty cycle, change shift points, readjust pressure for individual gear, change gear ratio. =More Coming Soon=

Resource Info

---------------

http://atdsm.com/

http://www.importperformancetrans.com/

MrGalantguy, DTP and Keith6110 like this

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If cool right, increase line pressure, & new fluid exchange regularly, Mitsu slushboxes can hold up around 400whp before considering having the tranny rebuild with upgrade clutches, modified valvebody, and torque converters.

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Jamie... how can I service the internal filter when you have to crack the case open? Why are drain and fills always recommended?

Sent from my SGH-I777 using Tapatalk 2

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from the service manuals, I can't find if or where the adjuster screw for valve body in the F4A51 transmission is, can anyone else confirms this?

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Jamie... how can I service the internal filter when you have to crack the case open? Why are drain and fills always recommended?

Sent from my SGH-I777 using Tapatalk 2

01+ transmission have an internal filter that can be only serviceable when the transmission is being overhaul. It is located within the transmission itself and its best to install a inline filter.

Drain and fill only remove about 3 to 4 quarts of fluid when there is a total of roughly 9 quarts thoughtout the entire system.

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01+ transmission have an internal filter that can be only serviceable when the transmission is being overhaul. It is located within the transmission itself and its best to install a inline filter.

Drain and fill only remove about 3 to 4 quarts of fluid when there is a total of roughly 9 quarts thoughtout the entire system.

There has to be a way to drain and fill and get it all out. My '00 only has the internal filter... the case is punched for the external filter, but no filter

Sent from my SGH-I777 using Tapatalk 2

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There has to be a way to drain and fill and get it all out. My '00 only has the internal filter... the case is punched for the external filter, but no filter

Sent from my SGH-I777 using Tapatalk 2

You can drain/fill it a a couple of times to get it clean but its going to take a long time.

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undo the two lines that go to the rad , one will be the feed and one the return , put sum more rubber hose on both lines  firmly and place those lines in a container, if you put car in nuteral and start car it will pump out almost all the trans oil, you MUST STOP the motor when the oil starts surging from the outfeed line into the container,Now is a good time to mark the outfeed line so you know witch one it is for later too. Refill and run car threw all gears to reload oil , thats by standing on the brakes , moving gear selector threw all the gears atleast 3 or 4 times, slowly, If you repeat again after say 50- 100 kms. Your trans and oil will be clean as and you can put a inline  magnafine filter in ..

mysticj and MrGalantguy like this

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One can rewire the three shift solenoids to allow quicker shifts by increasing the amount of voltage to them. The process is similar to a fuel pump rewire mod.

foxbrand likes this

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