1G Auto transmission acting funny

[dsmcoder]

I have a 1991 Mitsubishi Eclipse GSX automatic with a chipped tcu for full line pressure at WOT which works great btw. The transmission shifts normally and doesn't slip in any gear. The problem I've been having just recently is when I have my car in overdrive and I keep my foot steady on the gas pedal the car randomly downshifts into 3rd for like half a second and then shifts back into overdrive right away. It's really annoying because when it downshifts it jerks the whole car and all that shifting can't be good for the tranny. I don't think the end clutch is bad because it was just replaced about 5000 miles ago and doesn't seem to slip at all.
Anyone know what could cause this? Any advice would be greatly appreciated, thanks in advance

 

[DSM_GSX01]

Ok did you check the fluid and if it is low it will give you a hard shift. And you dont want to drive a auto transmission low, it will burn up the clutches and ruin seals and you will be doing a rebuild.

 

[MJBean420]

Go on IPT's website and get a clutch pack kit. Its probably your clutch pack getting warn. Happens every so often with us auto guys. It seems like the trans want to kick into 3rd gear at lower speeds, right? The teeth are probably warn...

 

[dsmcoder]

Go on IPT's website and get a clutch pack kit. Its probably your clutch pack getting warn. Happens every so often with us auto guys. It seems like the trans want to kick into 3rd gear at lower speeds, right? The teeth are probably warn...

Well actually it kicks into 3rd at both low and high speeds. And the clutch pack was replaced with IPT's clutch pack kit only about 5,000 miles ago so I would think they should last a little longer than that.

Also I checked the fluid and it's the proper level.

Could anything else cause this or does a bad clutch pack seem to be the culprit?

 

[dsmcoder]

Could it possibly be a soleniod problem? The shift from 4th to 3rd is a very hard shift when this problem is happening compared to when it's in 4th and I turn the overdrive button off, then it's a smooth shift.

 

[black97spyder]

The same thing was happening to my spyder. Well from what I've put together, the trans was pretty worn out from being extremely low on fluid and when the trans temp would get hot after driving for awhile is the only time it'd do it.

I believe It's the heat that was causing mine.

 

[dsmcoder]

The same thing was happening to my spyder. Well from what I've put together, the trans was pretty worn out from being extremely low on fluid and when the trans temp would get hot after driving for awhile is the only time it'd do it.

I believe It's the heat that was causing mine.

I think you're right about it only happening after the car is warm because when I first start driving it won't do it. I have the proper fluid level in it so I'm not sure why it'd overheat. Also the trans light isn't turning on so it can't be too hot. I was almost considering throwing a bottle of Lucus transmission stop slip in there and see if it does anything. I've only heard good results about it, anyone else wanna chime in?

 

[amrit9988]

mines doing the same thing

 

[black97spyder]

Both of my autos do it from time to time, and yea It's annoying as hell but the only conclusion I could come up with had to do with heat. But I doubt thats right because one of my autos has an IPT 12"x11"x1.5" trans cooler and hasn't ever seen anything over 165* while driving (have seen 185ish when sitting still in traffic) so i know there's not a heat Problem there.... Kinda has me stumped too but i just live with it

 

[amrit9988]

im going to change end clutches, inspect valve body for clogs, change filter and fluid, all in all i dont care unless im doing 43mph and have just beat on it. there must be a reason and I will figure it out, its only after the fluid gets hot that this happens.

 

[VetoJuice]

That would be a good start, perhaps try a shift box and see if it does it when you have it in OD with the shift box controlling things?

If it doesn't then it could be TCU related, if it does then might be mechanical.
It could help you figure out the problem and a shift box is a great investment anyways!

 

[VisegripMech]

I was having similar issues and unpluged/plugged-in/wiggled all the connectors and shazaam problem magically disappeared

 

[dsmcoder]

I installed the fourced four shift box and now I can stay in overdrive but it will not go in 1st or second gear. On the shift box gear selector when I'm in 1st gear I'm actually in 4th, when I'm in 2nd I'm actually in 3rd, when I'm in 3rd I'm in 3rd and when I'm in 4th I'm in 4th. Any ideas on what could be going on here?