it all started to happen after when kicking it to go faster on the highway with no exhaust and had been sitting all winter long and just moved back and forth in the snow. I was already doing 65 and kicked the pedal all the way to the floor. after that ride it would go into 2nd @ over 3k rpm.tried seafoam after trying trans-x that made it start to shift a little sooner and much better after warm-up.i am assuming that it would be #2 and #3(since it shifts hard into 3rd as well even hot)shift solenoids that need to be replaced(I'm hoping).I had check engine light on.scanned for the other little things and corrected them. I used my buddies snap on solaris scan tool and tried to see if any tranny codes- but nothing. I did a drive test in real time running mode and saw that those solenoids are on while parked and turn off when the car is moving.i took a brief look in the stupid Haynes manual tranny book and they don't list the 4t60e tranny only the 4t60.they show a pic of the solenoids and that there are 3 solenoids, and the od but they don't tell you which ones are for which gear.i don't also know which type of solenoids to order from advance auto. they list 2 different types with no specs to what tranny they fit.is this my problem or do I have deeper tranny problems that I won't be able to fix myself? thank yew:mex

When you had the CE Light on what codes or work was performed Mike?
Having a good state of tune, new fuel air/ filter, plugs/wires, clean throttle body etc can make the car run better/shift better as well.. sounds like u did some good work there..though..
When was the last time you changed the transmission fluid & filter? Dex VI (6) can make a nice improvement in shifting as well.
Quite often varnish builds up in accumulator/ valve bodies and solenoids. Did u use Trans Tune by Seafoam? It will remove help to remove varnish with normal driving & hwy combined and if shifts then improved, maybe new Dex 6 is now in order and allows you to see if there are any particulate matter in pan.
I am not sure on the 4t60e location of solenoids, I am sure another member will chime in soon.

I believe this is on your 94 Bonneville ..Can you please take a minute & update your profile please. This link will allow you to add the info quickly.-Thanks!
https://www.gmforum.com/profile.php?do=editprofile

The 2 different solonoides are Holley and bosh. They started using the bosh set up after 2002. I would steer clear of aftermarket solonoides and pay the money and buy them from the dealer or order AC delco from Rockauto.com.

the codes that I got were p0134- o2 sensor,lean idle mix,p1626-passkey,and p1561- cruise control vent solenoid.i checked plugs, wires, and air filter last night.i checked iac. I changed tranny fluid 2 years ago, it ran beautiful back then and just up until the winter and that gas pedal kickdown on highway.i used the fluid that was stamped on dipstick.i don't believe they specify using dex 6.should I try that? yes, I used trans x first for a couple hundred miles and than used on top of that seafoam trans tune.after which the car shifted quicker but still hard when hot.it'* worst when cold.

A visual inspection of plugs and wires isn't going to prove anything. Unless you know exactly what to look for and how to test the wires.

I wouldn't even consider touching the trans until those codes are fixed and cleared. Believe me, you don't want to know where those shift solenoids are and that you would rather do a complete tuneup and make the engine repairs first when I do tell you where those solenoids are.

So, get those codes fixed and cleared and then we'll move on. Otherwise, we're wasting time chasing ghosts on a trans.

codes are clear. I know how to check plugs and wires.i knew that a tune wouldn't make the tranny run any better unless the car was running really bad.when doin a real time scan, the solenoids are on and on standby when the engine is running -car parked. when driven and past those gears the solenoids are off.So they work and aren't the problem because they would've showed up in the tranny diagnostic mode.Will dex 6 fluid help or hurt?

What did you do to clear those codes? Did you make repairs or did you just use a scanner to clear them?

Depending on the emission code failure, it can actually cause a transmission to shift differently. Like I said earlier, fix the codes first.

I changed the o2 sensor.the other codes which I believe are soft codes that don't make the check eng light come on.then cleared em' through the scanner. light hasn't come on since I've been driving her around hard.

I am wondering if something is sticky in the 2-3 shift accumulator bore, accessible once trans pan is removed.
Is it possible a spring may not be working right/broken?
I wonder if inspecting is worth while, and scuffing the 1-2 & 2-3 bore walls might help.
I used 1000 grit emery cloth sandpaper, wet with trans fluid to clean my accumulator bores