2003 GT Automatic Transmission Questions
 

Hey. How much power can the stock auto tranny handle? Some factory trannys can handle 2 or 3 times the factory output, while others are built just to barely hang in there off the production floor. I have no idea what the capabilities of the mustang auto tranny are.

Thanks,

Oliver

I didnt really take care if my tranny and it died prematurely. The only thing I can tell you is to look up the J-Mod on google and do that to the stock trans. This will firm up your shifts without putting extra wear on the pumps. Doing this will make your shifts firmer and help hold up against the extra torque and horsepower.

I was pushing 400 whp and 400 wtq when it started to shift late at WOT. I would have to let off the peddle so it would shift. I knew it was matter of time before I actually broke something in it. I currently run a Performance Automatic Competition built AODE. Been working like a champ for the past 4 years.

Get it's officially a 4R75W tranny in the 2003. looked up the j-mod..pretty cheap might as well try it out. Found a nifty site http://www.tccoa.com/articles/tranny...on/index.shtml

I was on my phone so I couldnt link anything. You found the right site.

If you search for the J-mod on here you can find a link to the newer version of that mod for new trannys. With that mod and a tranny cooler they can hold around 450rwhp.

Dang that's all? I'm looking to reliably manage about 600.
Who makes good aftermarket trannys that are smoothy and streetable not for all out drag?

You may want to look at a built C4 to save on some money but that only has 3 gears. A built 4R70W/AODE to handle that much power is going to cost you around 3 grand. Then you have to look at a converter and that will run another 800-1k to handle that sort of power. The only people I would use for built automatics is Darrin at BC automotive dude builds some mean 4R70W's and my second choice would be Performance Automatic. With that power level you will probably have to use a manual valve body because the shift commands from the computer probably wont be fast enough.

You may want to look at a 26 spline T-56 or go with a TKO 600 to save a little bit of money.

Its a stock transmission in a car that made 260hp stock. I think 450rwhp is pretty good for a stock tranny lol.

w00t to that. 450lbs of tq is a huge amount of force to a steel bar to stand up to. Even a T56 could use a new input shaft at those power levels.

In that case, I'll have to tone down the boost until funds role in for a new tranny.

If i DID do a manual swap...does it suck? i mean i'd just have to put a pilot bearing in the crank, buy a clutch, a clutch pedal, slave cylinder..blah blah....

is driveshaft length and tranny mounting the same?
Is shifter location the same?

Just rock the auto its fun with the J-mod done to it.