AT tranny problem??

[dave2953]

I have a 91 turbo eclipse (FWD) w/ an auto tranny (i know autos suck)
Anyway, the tranny shifts great when under normal conditions, but at highway speeds if you punch the accelerator to the floor the tranny downshifts hard as hell. The engine makes all kinds of noise because of the high revs, but it doesn't really go anywhere. About 1 or 2 seconds after it downshifts, it goes back to gear it was in, and shifts really hard again. I am not sure if this is a modulator problem or what. I am thinking about swapping to a 5 speed, but I know that's a #@%#@%#@%#@%#@% to do.
Any information you all could provide would be much appreciated.

Thanks for the space.

Dave

 

[1gjohn]

dude,i have the same exact problem with my 91 awd,I've been working on it for months trying to get it running right.Im borrowing a logger this week to try to see if it can pin point anything.I'll let you know if i find anything.I also thought of going 5 speed but when the new engine goes in so does a nitrous kit and with out shifting(5 speed).I think it will be better for drag racing.Also there is a 3000 to 4000 stall converter coming out for our cars very soon.You can pick the stall you want .Mine will be 3500.with a end clutch kit and a shift kit,it should launch as well as a stick shift.

 

[boost]

No this wouldnt be a modulator problem, your trans doesnt have one anyway. Auto trans are hard to diagnose without having a scanner, like one from SNAP-ON, and a pressure gauge on the trans. Mitsubishi auto trannys are known for electrical problems, solenoids, speed sensors, etc... If your tranny is broken, mechanically, they usally burn up bad and take the cases out. Take the car to good transmission shop, not a general repair shop. Unless your familliar with auto transmissions, scanning for codes isnt going to help you.

 

[tsi91at]

If you have an electrical prob, the car will go into "limp mode". Which means you have 3rd gear and reverse only.

You can always check around the outside of the tranny for loose or cut wires. If one comes loose, you will know it.

You have a TCU (transmission control unit) BTW. They can go bad as well.

Now, You hit OD and nothing happens or revs high (4th gear no go). It is most likely the end clutches (see my page here: http://www.plymouthlaser.com/ec.htm) This will show you why. The OEM plates bend and bind the clutch. Usually the end clutch is the first to go on the AT.

The other case is the end clutch tube is wrong in the valve body (usually after a rebuild). Once again, that is the shift kit fix.

Check the fluid level in Neutral (Car hot) after shifting this pattern: P-R-N-3-2-1-2-3-N . If it is off, add or remove. THese trannys are sensitive to fluid levels. I ONLY use Diamond ATF or B&M Trick Shift. The final thing, change the tranny filter as suggested. I do mine every 30K.

ATs only suck if you do not do the required fixes (shift kit and End clutch). These are for prevention as well as performance.

My AT will beat a lot of 5 speeds.... Now, my 5 speed is the fastest w/o a doubt.
BUT, The AT has had the transmission break 0 times. The 5 speed will come out for the second time as soon as the 3rd gear sychro completely goes.


Charles
http://www.plymouthlaser.com

 

[1gjohn]

Is there a way to check the TCU to see if its bad?