Auto slipping in second gear only :(

[EagleTalonTim]

Ok, Here is the deal. I just got done fixing my tranny problem last week where my magnets some how exploded in the bottom of the pan and one of the pieces was clogging a port making my tranny make a whinning sound. I drove like this for about a week since I did not have the time to fix it. It sounded like the tranny was sucking air and there were tiny air bubbles on the dip stick. I fixed the problem and replaced the filter and fluid all at the same time. This tranny was used which I got from a JDM website and I have had it in my car for about 1 year with no problems at all. When I got the tranny, I just checked the fluid to make sure it was full and not burnt and everything was ok. Right after I replaced everything, I took it for a test drive and noticed that when under heavy boost, my second gear slips bad. Would this be my end clutches worn out or something worse? As the title says, it slips only in second gear. First gear pulls perfect and third and fourth pull perfect as well.

 

[ramsack]

are you sure it's only 2nd and not 2nd AND 4th (overdrive)? if so then it is your band that holds the whole rotating assembly to give you 2nd and 4th gear. the end clutch is only for 4th. i would get a trans rebuild kit from ipt if you are comfortable doing such a job. i would also get a shift kit to keep shifts firm instead of the stock gradual shifts that tend to wear stuff out. it will also raise line pressure so your clutches will have more force applied.

 

[EagleTalonTim]

I do not have a TCU since I drive with my shift box. My shift box has 100% line pressure every shift no matter what. I have been driving with it for about 3 years now. I am 100% sure it only slips in 2nd and not 4th since I have been in 4th gear and gone WOT all the way to 110 and nothing slipped.

 

[ramsack]

you have 100% line pressure with the stock spring. there is no separate clutch for 2nd gear.

http://www.freewebs.com/mitsu-info/Auto Trans Diagnosis (F4A21, F4A22, F4A23).pdf

if you go to page 3 it has a chart that shows you what clutches are on in what gear as well as the braking bands. it may help you diagnose but you aren't even using the tcu anymore.

i would also take the valve body out and clean the hell out of every crevice on it to look like new. you could be losing pressure somewhere when the 2nd gear combo of solenoids is activated. doesn't hurt or cost anything to clean things up. well maybe getting something like brake clean to do it is the cost.

 

[EagleTalonTim]

I have never tore into an Auto tranny before so I would have no idea what the bands would look like or how far down I would have to tear into it before I got to them. If I have to remove the tranny to fix this, it probably will not happen till summer when I can ride my motorcycle to work.

 

[ramsack]

i would at least try cleaning the valve body and see if there is an improvement. it takes a couple hours and i'd take a picture of where things go if you aren't good memorizing small parts type stuff. only thing you need is an inch-lb torque wrench or you will ruin it. valve bodies look more complicated than they really are.