Trans advise re reverse lock-out?

[Nadine UK GTS]

Can anyone offer a little advise please…I bought another trans (from a ’95 RT/10) and had it rebuilt over here by a UK company (this company handles all Aston Martins T56 warranty work etc so that’s why I went to them). I’m having to shift from 4th across into 6th, as I have ‘lost’ 5th gear already (flying miles running dextronIII) anyway…I’ve noticed the reverse lock-out doesn’t seem to be working?! With the cold weather until the trans warms up, it’s a little stiff to shift, and when firmly going across to the right with the shifter, it feels like it’s wanting to slip over to select reverse!! I’ve not a chance to check, but when I installed the trans, it visually had a rev lock-out solenoid in place, and I remember my OE ’97 GTS wiring loom plugged straight up to it. I’m assuming the rev lock-out is functional on ’95 RT/10’s? I’m also assuming the PCM switches it the same way (haven’t had a chance to look in the manual yet and only have GTS, but guessing it powers the rev lock-out solenoid when the vehicle is stationary, which would pull back a pin to allow select of rev)? I was going to have the same company rebuild it, but, could it have been possible the gearbox builders disabled the reverse lock out? Or there is a wiring problem? If the reverse lock-out didn’t work, I’m guessing you wouldn’t be able to get reverse? Thanks for any advise.

 

[AviP]

Reverse lockout was added sometime around 04/04/93 according to the registry on this site, so you should have reverse lockout in the transmission. I would suspect the rebuild. Sorry couldn't be more helpful.

 

[Ron]

The reverse lock out in GENII's at least, is energized to allow reverse selection and de-energized to prevent, therefore when the car is off, reverse is locked out. With ignition on, and no movement, it's powered and allows reverse selection.

 

[Viper Wizard]

Hi Nadine,

This is what the service manual says about the reverse lock-out:

"The reverse lockout soleniod prevents the operator from shifting into reverse when the vehicle speed is greater then 5 MPH. When vehicle speed is less than 5 MPH, the PCM provides a ground [earth] for the soleniod [energized] and allows shifting. When vehicle speed is greater than 5 MPH, the soleniod is deactivated and prevents the transmission from being shifted into reverse."

Wires on connector:
18g DB/GY fused ignition switch output [run/start]
18g LB/BK reverse lock-out soleniod control [ground from PCM]
[GENI's are the same way.]

I've repaired a few of them and it is a very touchy system! If you can push past it, that tells me that the soleniod is working mechanical and it's not jamed. So it's got to be an electrical issue, with the key on see if you have 12 volts at the DB/GY wire. Now comes the fun part, hook up your volt meter to the LB/BK wire and start to spin your driveline. If your wires are long enough off your meter and the back wheels are off the ground you should be able to check it yourself to see if the ground/earth goes on/off above/below 5 MPH. If they are both there [+ & -], then it's either a bad connector or a bad soleniod. If you have no + or -, then the problem is forward of the soleniod.

Hope this helps?

Hey JW this is your old tranny! It has gone faster with Nadine!!

 

[Tom F&L GoR]

On my '94 the reverse solenoid has (had) some washers that the internal spring for the plunger to push against. The washer broke and wedged itself next the the plunger, so it was permanently in the "don't prevent reverse" position. Then one day the washer shifted, and it was permanently in the "prevent reverse" position. Believe me, it was far more effort than an energized solenoid. Only then did I realize it had not worked properly for a long time.

Step one in the diagnosis might be to remove the solenoid and energize it on the bench to see if it works at all. If not, you can use the skip shift solenoid (which you don't use anyway) as a replacement. I have a previous post on this, but because of my advance age, can't remember the details at the moment...

 

[Nadine UK GTS]

Thanks Guys, good info, cheers.

 

[CSTER]

I'm curious. Is the "reverse lock-out" designed so that you absolutely cannot move the gear shift past 5th gear, over into reverse or is it just a mechanism that keeps you from actually engaging reverse. Basically, if you're at full-throttle in 4th gear and want to go into 5th, you can simply disengage 4th and move the shifter up and over as hard as you want and the shifter will still only select 5th gear???

 

[Viper Wizard]

Hey Christian,
Yes you can push past the lock-out soleniod! It will take some effort but it can be done!

 

[hemibeep]

.