97 C5 wont shift into 4th even with VCM controls

[Chevy406]

I spent just a few minutes on a friend's '97 Corvette that he recently bought. It has a "built" 4L60E and a pretty stout LS1 engine. The transmission wasn't shifting 1-2 at WOT which I fixed by dropping the rpm & speed. But the main issue is that it never shifts into 4th, regardless of driving style. I was able to command gears 2 and 3 using the VCM controls, but commanding 4th didn't make a difference. I told him to have someone test the 3-4 solenoid, but I thought I would also check here to see if that was the right call. If the transmission does not shift 3-4 using VCM controls, is it correct to assume that solenoid is not working or else it's another physical problem in the transmission?

Here is the tune I pulled off his car.

[DSteck]

Make sure the trans isn't low on fluid. I've seen some weird, dumb stuff happen when they're low.

[Chevy406]

Thanks for the idea. I bet nobody has even checked that.

[flame]

There is no seperate solenoid for 3-4. The 4L60E uses 2 shift solenoids for upshifts 1-2, 2-3

1st is on,on
2nd is off, on
3rd is off, off
4th is on, off

[Chevy406]

Thanks for posting that Flame. I've obviously never been inside a 4L60E transmission. What do you think about the transmission not shifting into 4th even with VCM controls? I need to check the fluid level when ever I can get my hands back on his car. But are there any other ideas?

[flame]

Since all the other gears work that means that the solenoids are functioning. If the fluid is full its time to pull it apart more then likely. I'm not a trans builder just have access to the info.