Hi everyone…

I bought this neglected Corvette and have set about its refurbishment. Primary issue has been that it would not go into drive, only Park, Neutral and Reverse. Previous owner suspected linkage, so I took my chances.

Couple of notes… when shifted into reverse, with rear reverse lights activating, it did nothing. Drop down one more gear into (presumed) neutral, and it would go in reverse. From there it would shift down once more and that was it. In the lowest gear (no response when shifted there) was lots of play, definitely not any defined OD, D, 1 or 2.

I got under there and after some research replaced one of the Shift Solenoids in the transmission pan (P/N 24230298) for about $30.

Lo and behold, it then would go into proper reverse, neutral, and then one more gear down, in which the car would move forward and drive. Though became apparent was only going into 1st and then shifting into second while in the mystery forward gear (I’m guessing overdrive?), no 3rd or 4th.

I assumed that I needed to get another of the same shift solenoids, and replace the other one in the pan (there were two, closely positioned next to one another, of which I changed one, chosen randomly).

So yesterday I got another solenoid, dropped the pan again, and swapped out the other solenoid. Now this solenoid I got from Pull-a-Part, out of a 1999 automatic Camaro.

I also swapped out the pan filter for the one I pulled from that Camaro.

I triumphantly put the pan back together and filled it with Valvoline Premium full synthetic (says multi-vehicle, Dexron VI, Macon LV, Toyota and Hyundai… apparently not the ideal fluid I’ve learned).

I started it up, shifted into drive… and nothing. Just like it was before. It goes into reverse, but not drive.

I have verified that I swapped the old solenoid, not simply removed the newer, good one I just installed last week. In now is the brand new one from last week, and the “new”-ish, one from pull a part.

What have I done? Why is it back as it was?

I suspected the fluid, but from more research sounds like that shouldn’t prevent functionality.

I suspected a bad solenoid from pull a part. But what happened to my first and second gears that had been working after more recently replacing? It would obviously be the most recently replaced solenoid, if it still went into first and second.

Please help!

 

You will need to let us know what year you have in order to get information. Including mileage of car would also help.

 

The best help I can give you is to stop buying transmission electronics from a junk yard. For about 100.00, you can get a new harness, all the solenoids (5) and a position (pressure manifold) switch. Replace those and check the wiring and connector of the exterior harness and go from there.

 

Oh okay I thought that was all visible in my profile.

it’s a 1994 LT1, and I am not certain of the mileage, as the cluster is one of the parts I’ve yet to get replaced and I cannot view the mileage. Or maybe I don’t know how? Cause it doesn’t appear to be shown automatically? Do I press a button? Noticed same with gas gauge? There is an actual button that says gas, but it’s not just shown from what I can tell.

 

Thanks for the reply. And I would love to do that. I probably should get all that stuff. But I’ve been spending so much everywhere else with repairs (completely new brake system, all new shocks… two that come to mind just in the past few days). So I’m trying to save wherever possible. I had hoped to do a more thorough transmission overhaul in a few months.

I think I will replace the second solenoid (in order that I replaced) with another of the new parts. Meaning the AC Delco solenoid I shared the part number of above.

But I still am puzzled as to why a positive change I already experienced from replacing the first solenoid, is undone by replacing the second? Had it remained as it was this morning and for the past week, with no change beyond first and second gears working, that would make the second solenoid obvious. But the fact it seems to have totally reverted to the state it was in a week ago, before I replaced the first solenoid (successfully) is what puzzles me.

 

Verify that when you move the shifter, the transmission lever moves accordingly. Ie, when in P, the trans is in P. When in R, trans is in R., etc. You should feel 7 distinct positions with the shifter.
^^ Do this next. ^^ Diagnosing your issues depends on knowing which position the Manual Valve in the transmission is in.

With no power to the transmission, or with no input from the ECM, the transmission default is 3rd gear only. Solenoid state OFF/OFF is 3rd gear. If neither shift solenoid (the 2 side by side at the rear) is operational or ON, the trans will be in 3rd gear with the shifter in D4 or D3. (I honestly don't know what it does with the shifter in D2 or D1 with solenoid state OFF/OFF.)

The transmission solenoids are powered from fuse #7 VALET. You should check that that fuse has power on both sides (use the little holes for your meter probe) with the key in RUN.

I'm wondering if there are other issues like a broken forward sprag? In a 60e, the Overrun clutch is not PCM controlled. The Overrun clutch is applied when the shifter is in D1, D2 or D3. Not in D4. I'm wondering if it won't move (no forward gears) because your sprag is busted. But if you manage to get the manual valve into D3 or below, it does? (Applying the Overrun clutch when the sprag is broken routes torque 'around' the broken sprag and the car moves.) But depending on which manual valve position is selected, and which shift solenoids are functioning or not, you get 1 or 2 gears, but then they 'go away' again.

You've got to sort out the shifter linkage so you know that the trans manual valve is in the position the shifter is in. The Pressure Switch Assembly tells the PCM what position the manual valve is in and the PCM shifts accordingly. If the PCM is being told a different position than the shifter position, its going to drive you nuts trying to figure it out. 7 distinct positions when you move the shifter. Cheers.

EDIT/ADD: Here's a place to begin to assess if there are internal issues other than solenoids or shift cable. Remove Fuse #7. Fire it up. With the transmission lever (not the shifter) in D4 the car should move in 3rd gear only. It will be lethargic from a stand still, but it is drivable.

 

Wow what amazing feedback! Thank you so much. This is what I was hoping for.

im gonna go and see what I can figure out and report back. I will say, there is no doubt, not 7 distinct positions. More like four. And right this moment, none which propel the car forward.

 

IHBD,

We talking about the small box by the master cylinder? (Shows as power accessory) With only a handful in a straight line? Or the box on side of the passenger side dash, interior of cab (shows as horn?)

Thank you again, in advance.

 

With the engine OFF but key in RUN to unlock the shifter, (park brake set or foot on service brake so car doesn't roll) push the button on top of the **** down; keep it down and move the shifter back to the next detent. You should be able to hear a faint click or thunk from the transmission. When the shifter is in a detent, with the button still depressed, move the shifter fore and aft. There should be almost zero play or slop. If there is, you have to find the source of the freeplay.

The cable between the shifter and the transmission can be the source of the 'slop' in the shifter linkage. The outer jacket tends to pull/push out of the swages that hold it at each end. Under the car is easy to check, look at the jacket where it goes into the swage for signs of it moving. To check the interior, you will have to remove the top of the console. When you manipulate the shifter nothing forward of the bracket should move. Again, it is usually the swages that get loose.

Another source of play is the bracket on the transmission held by (2) of the pan bolts. It is common for these bolts to get loose, introduce play, and it is not possible to get into D1. You've had the pan off, you are putting the bracket back on, yes? And the bracket is present, yes? I.e. a previous individual didn't remove it but not put it back on?

Fuse #7 VALET is in the Instrument Panel fuse box. (Open the passenger door.)

 

Yes I’ve had the pan off, and put the bracket back on. Still working on figuring out the source of the play in the gears. But for now, I got it rolling and all is more or less well.

Turns out, that it was the variable speed sensor. It came unplugged, and the connector was chewed up. I replaced the pigtail for $12, and that took care of not going into drive.

I still don’t feel seven distinct gears. So I will try your suggestions and see what I can figure out.

Thank you again.