How does reverse lockout solenoid work?
 

Still having huge problem getting tranny into reverse.
Same with engine running, or engine off.
When the problem first started, I could put it into reverse easily with the engine off.

I have a new solenoid to install - hoping this is the problem.

The new solenoid - the plunger is fully extended when power is not applied.
Pushes in easily with my finger.
Applying 12V to it retracts the plunger

I haven't taken the mounting assembly off yet, as I will have to lower the cradle a bit to get in there. Tried as it is, and can't quite get onto the 13mm bolt.
I know others have been able to do theirs without lowering, but I can't quite get enough room.

How does the lockout assembly work?
Is the (12V applied) plunger retracted mode the lockout position?

What goes on in the housing when reverse is locked out?

I'm hoping my problem is that the plunger is sticking in the lockout position.

Thanks

Needs 12v sent to retract it and allow you to go into reverse. This way if a wire or plug get disconnected it wont let you go into reverse.

Looking for what's happening inside the piece that bolts to the tranny.
Expecting some type of lever action -- but the piston only needs a very minimal pressure to push in as it's sitting on my bench.

Not disputing what you said -- but I have always been able to shift it into reverse with the ignition off.
If it requires 12V and the piston to be retracted, it seems like I should not have been able to shift it into reverse with the ignition off...????

https://cdn.shopify.com/s/files/1/06...g?v=1551730145f
Found this picture of the mechanism.
Based on this, the solenoid piston has to be retracted so the other piston can slide into the area the solenoid piston occupies when not retracted.

Since I have shifted into reverse sometimes with the ignition off, implies the solenoid may be sticking in the retracted position (sometimes).
But I could not put it into reverse with the engine running, so solenoid piston not retracted.

So I will replace the old solenoid.
I will have to check the power to the solenoid and hope it's not a problem with the wiring or connector

Before you replace anything check this micro fuse. Something similar happened to me after and exhaust swap and it was this fuse was blown. It's kind of hard to see but it is circled in blue. Quick and easy check before spending time to replace the solenoid.
https://cimg3.ibsrv.net/gimg/www.cor...6f97c8de83.jpg

Wow, I never even thought to look for a fuse.
I should be back to the garage later in the week and will check this.
That would really be a stroke of luck.

Thanks !!

I hope that's all it is for you also. Quick easy and cheap for just a 25 amp micro fuse. Good luck!

Unfortunately the fuse is good.
Checked with a continuity tester.

So it will be drop the cradle a bit so I can get the solenoid out.

Good luck, Joel.

No joy in muddville….

We got the whole assembly out.
Shifts into reverse with everything out.
A bit notchy, and

Old solenoid tested good, and put in the new one anyway.

Tested power getting to solenoid when ignition turns on, and retracts when power is turned off.
That part works properly.
The other part of the assembly seemed to work easily with the plunger moving out and in.
With solenoid installed on workbench would not depress, as expected.

Re-installed assembly with new solenoid.

FUBAR - can't get into reverse with power on, and engine not running
Can't get in with engine running.

The thing I now realize we didn't check, was the plunger going into the assembly with power applied to the solenoid, so that plunger is retracted..

Have to pull it out again and check that.

Could take the guts out of the assembly, and not have a reverse lockout.

Maybe something is bent in the tranny - but then shouldn't have worked with the whole assembly out.

Prefer not to go for a tranny rebuild yet.....

.

hmm super weird. Curious to what you find

The continuing saga...

Took off the entire assembly, and gutted the plunger assembly that goes into the tranny.
So now there is NO reverse lockout at all.

With the engine off, it shifts thru all gears, including reverse perfectly.

Start the engine.
Will not shift into reverse with the engine running -- well, it can if I seriously force it which feels like I may bend or break something.
There is no grinding or any sound of distress trying to go into reverse.
Just nogo !!

The clutch pedal has about 1/4" of play at the top.
Shifting into any other gear is fine.

So I don't believe the clutch is dragging.

MGW shifter has been aligned and re-aligned with the alignment jig multiple times.
Slides in like butter with the engine off. Did check shifting to be sure it was reverse not 5th.

Started engine with the tranny in Reverse position, car moves backwards.
Clutch pedal engages more than an inch off the floor,.or maybe a tick higher.

If the shifter rods or something was bent, it shouldn't go thru all gears so easily with the engine off....???

Totally baffled !!!

Well.. I learned (in another thread) that apparently there is a syncro set for reverse.. Now, how those could possibly go bad, no idea. Just something to consider.

I will also say I noticed on my old T56 in the C5 it was pretty common to have to put the car in 1st, roll it forward about 6 inches, then it would slide right into reverse. Maybe try that, see what happens. :cheers:

Didn't think of trying the 1st to reverse, although I did 3/4 multiple times before trying reverse.
I'll give that a shot when I can get to the garage next Tues.

Thanks!

Still a nogo.

Reverse is fine with the engine off.

Will not go in with engine running.

fubar !!!!

What you are describing is a classic dragging clutch, but I suppose there could be another explanation.

I would contact Rick at RKT, describe what's going on and what you've done so far.. :cheers:

Thanks for the try, good guess, and that's highly unlikely. One of the first thing I checked.
There is free play in the clutch pedal at the top, and it does not engage in any gear until it's about 1-1/2" off the floor.
I'll give Rick a call -- I'm open to any thoughts and suggestions.

Wondering if it could be something worn or bent in the shifter rods between the shifter and tranny ?

Car only has 10K miles on it, and it's mostly track miles.

I have a 2007 Z06 that entry into reverse gear started to get tricky last year. Not driven much sense, but I have gone the path you have and I still do not have reverse. Rick at RKT will be involved with my transmission in the coming months. Best guess is a missing pad the reverse shift fork uses to engage with in the case. I guess GM uses two plastic pads, pictures sent to me by Rick, and they are known to wear down or come apart. There is a brass replacement part(s) he recommends. I have no idea if this is the real issue at this time. My reverse "gate" is missing. The shifter can be moved to where reverse should be, solenoid verified and another same year car to compare movement, but the gate is not engaged. Feels spongy. Every 1 out of, say, 35-40 tries, I get reverse. No longer driving car. Preparing to drop cradle and ship trans/diff to RKT.

If you PM me an email address, I can forward pictures of the pads to you. Rick sent the pictures to me and I have talked to him over the phone about my symptoms.
I am replacing clutch with all the work being done, but all forward gears are fine and never grind: even fast shifts.

Sending email in PM. Certainly like to see the pic.

I spoke with Rick yesterday (Fri), and he thinks it might be the reverse blocking ring. It's only when the engine is running that it won't go into reverse.
My tranny is ok with all other gears too.
As unlikely as it might be, I'm going to replace the fluid with Amsoil on Monday, and see if changes anything.