Transmission Not shifting properly

[Babucher]

I've got a 98 exp. 5.4 Eddy, and since this past winter anytime I first start to drive the tranny shifts normally from 1st to 2nd and 2nd to 3rd, then there's a quick shift (I don't what this is from) and then into Over Drive. When I'm having the problem it's the quick shift between 3rd and Over Drive, it just doesn't make this shift. When the problem first occurred, it was accompanied by the Over Drive "On/Off" light flashing. The Ford dealers told me this indicated an electrical problem in the tranny. The light only flashed for a couple of days before quitting. The shift problem is now only noticable when it's cool out. Is not evident after a few miles of driving. Any Help will be appreciated!!

 

[green03]

is it slipping into 4th (reving or "flairing" the RPMs) before it shifts or is it just not making the shift into 4th at all. If it is not ever getting to 4th then i would suspect a faulty connection to the overdrive servo solonoid or the solonoid itself is on it's way out. sometimes the connector to the transmission gets corroded and causes problems like these.
Matt

 

[Babucher]

No, it makes the shift into 4th (or over drive) just fine, it's like there's a shift in between 3rd and 4th ( someone said that it was the torque converter locking), but I'm not sure if this is correct or not. The truck seems to run about 500 - 600 rpm higher in OD when this shift doesn't take place. Hope this add. info helps!

Thanks, Brad

 

[green03]

Yes, under light throttle conditions the converter will lock before it shifts into overdrive and harder throttle will make it stay unlocked untill you are in overdrive. I programmed mine to not lock the converter untill it is in overdrive because it runs better around town if you leave the converter unlocked.
If it is harsh or shuddering when the converter locks then you probably just need a good transmission flush and fluid replacement. Use Mercon V fluid to help prevent torque converter clutch shutter, and it is synthetic so it is better for the trans. I don't know what your year model calls for, but you can use the Mercon V in an application that calls for Mercon IV.
Matt

 

[Babucher]

But, would this explain why the O.D. light was flashing for a couple of days?? I'm just worried about my Expy, and love her so, that I don't want to see her come to any harm!!

 

[green03]

the two issues may be unrelated. I thought the hard shift was happening more often and the light only flashed once.
Is this correct?
Matt

 

[green03]

So if the converter isn't locking up and your trans light is flashing then it could be the TCC (Torque Converter Clutch) solonoid or the wiring that powers it. The solonoid is just an electronic valve that merely lets fluid through it when power is applied. The light comes on when it senses an open circuit. It is easily replaceable by a trans shop. The good news is that it won't really hurt if the converter doesn't lock once in a while. When it quits locking completly or for a couple of shifts then the light will come on. Like I said earlier, corrosion in the transmission harness pins can cause this and since it is happening off and on I would suspect that it is loose/coorded wiring causing it.
Matt

 

[Babucher]

Ok, let me see if I can clairify this all, The light only came on once back in January. It flashed for a couple of days but has NOT flashed since. This was after some aggressive driving in snow drifts and I attrib. it to water freezing around the contacts (as you pointed out). But since last winter, it seems to have a reoccuring problem of the torque converter not locking in at the proper time or at all, after sitting over night or when it's very cool out. After a few miles everything works as it should I guess. As I've heard others talk about the shift pattern being less than desirable on the big brutes I guess it's how it should be, after driving a few miles. Thanks for all your input. This is such a great forum for those of us who love the beast!!

 

[green03]

Cold fluid can cause stuff like this to happen. It gets worse when the fluid is dirty because it makes it thicker. The Mercon V is a synthetic fluid that flows better at cold temperatures and protects better when hot too. I don't know when ford switched to it, but it is backwards compatable stuff. When was your last fluid/filter change on the trans?
Matt

 

[Babucher]

As much as I hate to admit it, but never in it's 125000 miles, aargg

 

[green03]

Dude!.............. That's all I'm going to say.
Get a flush service from the local Jiffy Lube or whomever has the machine. That will replace all the fluid in the trans including the torque converter. Get it done now before all that metal starts making the valve body get sticky and cause a really expensive repair. You will be suprised how much grit (clutch material) and metal shavings get past the trans filter.........
The 90 dollar flush service is really worth not having to pay a trans shop to work on it........
Matt

 

[Babucher]

Thanks man, of course all this falls under the heading of DUHH!
But I do appreciate the input.

Thanks
Brad

 

[Babucher]

Matt, just wanted to let you know, I got the tranny flush and fill this weekend!! Man what a differance that made!! I guess I just didn't realize what kinda shape the tranny was in ?!?! Once again thanks for the input, it sometimes just takes someone on the outside to help us see the obvious!
Brad