OK, i've been procrastinating on this problem for a long time. Time to finally figure it out. 94 Z28, tranny was supposedly rebuilt about 10k miles ago. It worked PERFECT before I parked it to rebuild a blown motor. I put a 3k stall in it, and drove it around (no tune) and noticed it was sluggish.

Well, now it has a stock motor in it with the same 3k stall. Here is what the transmission does do.

1st gear... not at all
2nd gear... check
3rd gear... check
4th gear... check
N... yup
R... indeed

Now, IF I put the car into D and go to take out... it pulls out in D!
If I put it in 2nd, it will pull out in 2nd.
It will not shift until I shift, no matter what RPM or throttle position.

Also, the stall will not lock up... It goes in to OD but it does not lock.

What do y'all figure?


EDIT: oh yea, if you put it in 1st and pull out... it pulls out in 2nd.

 

Are you ABSOLUTELY sure you're feeling 4th gear, and not lock-up? No 1st and 4th makes more sense, and would be easy to diagnose.

I would lean toward the transmission being in "limp mode", but if that were the case, you wouldn't have 4th.

Is it throwing an "SES" light? Both solenoids "OFF" is 3rd gear, but you can get a manual 2nd. Many times it's traced back to something as easy as a blown fuse, or a bad wire.

Frank
CPT

 

Well, the only reason I think I can FEEL 4th... when i gear down from 4\3rd... i can feel it. That is the only sign though

as for the ses code... I dont remember. I'll have to get around to getting my computer loaded up and scan the car. But there is not light coming on...

 

Now we're on to something. That "something" you feel on the 4-3 manual downshift is your over-run clutches coming on. Probably not an actual 4-3 downshift. Check your fuses. If all fuses are good, check for 12 volts at pin "E" of your case connector. Unplug it from the transmission and check the cavity that has only one pin in the row. It will be right above a row that has all 6 cavities filled.
If you have juice there, then it may be the computer commanding fail safe. We won't have an idea of what's causing it until you have a chance to get it scanned.

Frank
CPT

 

What are over-run clutches?

 

over-run clutches are only applied (in a 4L60E) in manual 1st, 2nd, and 3rd. When you move the shifter from O/D to manual 3rd, your applying them.
Over-run clutches apply to provide "engine braking".

Frank
CPT

 

Wow, pretty neat Frank!

I got a chance to scan my car so far...

90 = TCC solonoid circuit
84 = 3-2 downshift feedback fault
82 = shift A solonoid fault

 

A bad "A" solenoid will cause a no 1st or 4th condition.

It still may be a power problem causing it, though. It's not likely all those solenoids failed at the same time.

Frank
CPT

 

sweet, I'll see what i can find tomorrow evening.

 

"check for 12 volts at pin "E" of your case connector"

Ok, fuses are good... I see the connector at the end of the transmission (speed sensor?) Is the case connector going to be on the top of the transmission? Can I get to it from underneath?

 

passenger side of transmission, right behind servo cover. Just above the pan rail, you'll find a harness that connects to the transmission.

Frank
CPT

 

do what they say. also since you put in new motor check all your grounds that you had.in fuse block there is a fuse for trans. put a volt meter in the pins and turn key on looking at meter. i seen a bad ignition gives it 4 volts than jumps to 13.a test light doesnt work to good for this.

 

OK, now that the intense heat is over... its time to figure out this thing! I got the harness loose and didnt really see a pin "E"... but I took out the ole trusty haynes book and the wiring schematic said the light green wire coming off of the tranny was the 1-2 shift wire. So I tested it at the harness (poked in the skin of the wire) But I don't think I found a good ground down there... didnt get anything with the key off, on, or started, so i went up to the pcm and went to the "Black" section i do believe?? Looked to see if the wiring schematic matched the spot of the PCM I was at... looked pretty good to me. So I poked and prodded the lt green there and got around 10 volts with the ignition set to "on". Tomorrow i'll try what jaquareats suggested!

 

k, after some help from my brother, i found that pin E is a pink wire...

I had two pink wires on this particular connector so I checked them both, they each had a bit over 10volts

 

well, i took it for a drive today... must have been a loose wire/bad connection somewhere in the system... all gears work, stall locks up... and dough nuts are better in 1st gear