93 rt10 5th gear
Discussion
Last couple of weeks I have "missed" 5th at least 4 times, judging by the noise made by the gearbox i reckon I am going through the gate and trying to select reverse, which would not be good.
It only happens in the 4th to 5th gearchange going up the box.
Never had a problem up until now, gearbox feels fine, so have I just become hyper sensitive to this gearchange and perhaps subconsciously pushing too hard, am I just a prat?
? or something else? 
It only happens in the 4th to 5th gearchange going up the box.
Never had a problem up until now, gearbox feels fine, so have I just become hyper sensitive to this gearchange and perhaps subconsciously pushing too hard, am I just a prat?
? or something else? 
Morning Kev,
There is a Lockout solenoid on reverse, which by the sound of things may have gone bad. With the engine and ignition all switched off how easy is it to push the gear stick into reverse? If it goes in pretty easily then my guess is that that is what has gone wrong. Generally with the ignition switched off the solenoid will have no power to it and should feel damn near impossible to push past. (I found this out whilst fitting my shifter last year, nearly put my shoulder out trying to get it in reverse, without realising it needed power to allow it in.)
There is a Lockout solenoid on reverse, which by the sound of things may have gone bad. With the engine and ignition all switched off how easy is it to push the gear stick into reverse? If it goes in pretty easily then my guess is that that is what has gone wrong. Generally with the ignition switched off the solenoid will have no power to it and should feel damn near impossible to push past. (I found this out whilst fitting my shifter last year, nearly put my shoulder out trying to get it in reverse, without realising it needed power to allow it in.)
Ok... Bit of extra info for you.
As a running change in 1993 (VIN 605) the reverse lockout was changed from a spring loaded detent, to a PCM controlled lockout solenoid. When the key is turned ON and vehicle speed is 3 mph or less, the PCM will energize the solenoid. A selector then pushes a spring loaded plunger past the solenoid thus allowing the the trans to be shifted into reverse. When the speed is greater than 3 mph, the solenoid is de-energized which blocks the plunger from passing the solenoid and getting to reverse.
If yours is prior to VIN 605 then it should have the spring detent and it is not PCM controlled...no wires....no fuse.
If you have a post VIN 605 car and have a fuse or wiring problem, the solenoid defaults to a no reverse condition. In others words, you would never get to reverse until the PCM could control it.
The reverse lockout solenoid must activate to ALLOW you to shift into reverse, it does not prevent it, so if the solenoid was damaged or if you disconnect the wiring to it you will never be able to get it into reverse.
However, if yours is pre VIN 605 then it has a simple detent not a lockout which means if you miss the gate for 5th, you get T56 internal component interference, which is apparently why the solenoid was added.
But! Is it possible to put a later car into reverse at speed?
Yes, according to Tremec's T56 tech manual! There are a couple of ways this could happen, one by operator error, and the other by component failure.
You can find it here- http://www.ttcautomotive.com/English/media/pdfs_au...
The reverse lockout solenoid has a plunger, that restricts the motion of the shift linkage. It actually does not come in contact with the reverse gear at all, but only acts to prevent the shift linkage from moving to the reverse position. The force applied by the shift lever is in the same axis as the motion of the solenoid plunger. The plunger is spring loaded, and is usually extended when the car is at speed, restricting the motion of the shift lever towards reverse. When the solenoid is de-energized, (above 5 mph) the driver must overcome the tension of the plunger spring to move the lever to reverse. This is spec'd at 30-50 lbs of force, but may be less if the spring is fatigued. The manual reccomends replacement if the force is not high enough. (See section 3-12-2 for tension specs) When the car is going less than 5 mph, the computer sends a 12vdc signal to the solenoid, causing it to retract against the spring tension. When the plunger retracts, the driver then only has to overcome the remaining 5 lbs of opposing force to move the shift lever towards reverse. That is the slight spring tension you feel when you select reverse.
The manual goes on to say that the device may be defeated by the driver, (they use the term "crash through" to describe this), and they also say the solenoid plunger may become stuck. The spring could also break, leaving the plunger retracted. If the plunger becomes stuck in the retracted position, there will be no way of preventing the driver from selecting reverse at any speed or in any direction of travel. So it is a possibility to either "crash through" the device by applying more than 30-50 lbs of force to it, or it may become stuck retracted. If its stuck in the retracted position, it wouldn't require the driver to "crash thru" it, just miss the gate towards 5th. Those are two possible scenarios where it would be possible to enter reverse at speed, according to Tremec's own technical publications.
Considering the torque Vipers exert on these T56's, I'd have to say they are pretty hardy. But as our cars get older, these issues become more critical.
Hopefully that covers all the bases Kev...
As a running change in 1993 (VIN 605) the reverse lockout was changed from a spring loaded detent, to a PCM controlled lockout solenoid. When the key is turned ON and vehicle speed is 3 mph or less, the PCM will energize the solenoid. A selector then pushes a spring loaded plunger past the solenoid thus allowing the the trans to be shifted into reverse. When the speed is greater than 3 mph, the solenoid is de-energized which blocks the plunger from passing the solenoid and getting to reverse.
If yours is prior to VIN 605 then it should have the spring detent and it is not PCM controlled...no wires....no fuse.
If you have a post VIN 605 car and have a fuse or wiring problem, the solenoid defaults to a no reverse condition. In others words, you would never get to reverse until the PCM could control it.
The reverse lockout solenoid must activate to ALLOW you to shift into reverse, it does not prevent it, so if the solenoid was damaged or if you disconnect the wiring to it you will never be able to get it into reverse.
However, if yours is pre VIN 605 then it has a simple detent not a lockout which means if you miss the gate for 5th, you get T56 internal component interference, which is apparently why the solenoid was added.
But! Is it possible to put a later car into reverse at speed?
Yes, according to Tremec's T56 tech manual! There are a couple of ways this could happen, one by operator error, and the other by component failure.
You can find it here- http://www.ttcautomotive.com/English/media/pdfs_au...
The reverse lockout solenoid has a plunger, that restricts the motion of the shift linkage. It actually does not come in contact with the reverse gear at all, but only acts to prevent the shift linkage from moving to the reverse position. The force applied by the shift lever is in the same axis as the motion of the solenoid plunger. The plunger is spring loaded, and is usually extended when the car is at speed, restricting the motion of the shift lever towards reverse. When the solenoid is de-energized, (above 5 mph) the driver must overcome the tension of the plunger spring to move the lever to reverse. This is spec'd at 30-50 lbs of force, but may be less if the spring is fatigued. The manual reccomends replacement if the force is not high enough. (See section 3-12-2 for tension specs) When the car is going less than 5 mph, the computer sends a 12vdc signal to the solenoid, causing it to retract against the spring tension. When the plunger retracts, the driver then only has to overcome the remaining 5 lbs of opposing force to move the shift lever towards reverse. That is the slight spring tension you feel when you select reverse.
The manual goes on to say that the device may be defeated by the driver, (they use the term "crash through" to describe this), and they also say the solenoid plunger may become stuck. The spring could also break, leaving the plunger retracted. If the plunger becomes stuck in the retracted position, there will be no way of preventing the driver from selecting reverse at any speed or in any direction of travel. So it is a possibility to either "crash through" the device by applying more than 30-50 lbs of force to it, or it may become stuck retracted. If its stuck in the retracted position, it wouldn't require the driver to "crash thru" it, just miss the gate towards 5th. Those are two possible scenarios where it would be possible to enter reverse at speed, according to Tremec's own technical publications.
Considering the torque Vipers exert on these T56's, I'd have to say they are pretty hardy. But as our cars get older, these issues become more critical.
Hopefully that covers all the bases Kev...
Edited by RT/10Dave on Monday 28th April 15:45
Thanks Dave,
My car is post VIN605 so it has a solenoid.
I have no trouble selecting reverse so I guess I conclude that the solenoid may be stuck retracted.
First thing to do will be to check the fuses, although in theory that should not be the problem.
I will e-mail the wizard for a price
In the meantime I think 4th to 6th may be a wise move!!!
My car is post VIN605 so it has a solenoid.
I have no trouble selecting reverse so I guess I conclude that the solenoid may be stuck retracted.
First thing to do will be to check the fuses, although in theory that should not be the problem.
I will e-mail the wizard for a price
In the meantime I think 4th to 6th may be a wise move!!!
Id say you have a short somewhere, as you said you cant get it in reverse with the ignition off (ie no power to retract the solenoid) but as soon as you turn on the ignition you can get reverse no matter what speed. so the solenoid is changing state just not controlled by the ECU.
I assume both the speedo and PCM are receiving a speed signal or does the ECU always think your parked.
good luck
I assume both the speedo and PCM are receiving a speed signal or does the ECU always think your parked.
good luck
Classic of Rev lock out solnoid fail, very easy to replace in situ on car, a bolt and seals on an O-ring, don't even need to drain the fluid. I've had to do several in last couple of years. Did bench test one (hooked upto a battery, was clicking but nothing mechanical happened) was shot! Other solinoids you can get going again, but not when this one failed. Do check wiring though, and what readings you're getting. The nylon pads on the forks wear badly / are weak on GenI/II T56s (upgrade to brass if you ever have the box apart).
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