Mustang and Ford Performance Forums banner

Reverse Lockout Solenoid - Tremec T56

28K views 36 replies 12 participants last post by  tmhutch 
#1 ·
I have put a '99 Cobra 32V engine into my '96 Mustang GT.
Now I got a Tremec T56 6-speed transmission that I want to swap in, replacing the stock T45.
The Tremec T56 (out of a 2003 Cobra) that I bought has an electrical connector on the left side of the shifter tower.
I was wondering if that is a Reverse Lockout? If it is: it needs to be connected to the brake pedal switch, right?
My existing T45 does not have a reverse lockout feature, so in that case I'll have to make up some wiring for it... or just install an additional switch somewhere that must be pressed while engaging reverse...
Or am I wrong altogether and the electrical connector is for something else?
 
#2 ·
Yes, that's a Reverse lockout solenoid. One way to energize it is to tie it into the brake light circuit, but that's not the only way. Some people opt for a separate switch to energize the solenoid when desired. I modified my shift knob by adding a momentary contact switch when I installed my T-56, but there are shift knobs out there that come with such switches already installed.

 
#3 ·
Taz- How exactly did you modify the momo knob; looked at your website, a very nice nice job. Did you drill out the top and what type of momentary switch did you get, any particular brand or catalog number you may recall?Did it require a tap, or just press fit. Were you able to route the wires without any difficulty? thanks for your time- m weiss
 
#5 ·
Thanks for the kind words.

I spent a lot of time modifying that Momo knob, but you could make it easy on yourself by just picking up a shift knob that is already equipped with a switch. There are several on the market that have momentary buttons - Hurst, among others, makes a couple different designs. One of those would give you a nearly plug-and-play installation.

I would have gone that route myself, except I wanted a knob that cosmetically matched my E-brake handle, and I wanted to keep the wires completely hidden. That project was a couple years ago, and I didn't record any notes at the time, so I apologize if my response is little vague. I used a Radio Shack #275-644 pushbutton. This is the part: momentary contact pushbutton.

I used the nut that came with the pushbutton to secure it to the top plate of my shift knob, but the knob I used is a multi-piece design, which made the modifications for the switch easier than they might have been. If yours is a solid piece, I imagine it would be easier for you to drill the knob and either tap it and thread the switch in from the top or drill a large enough passage to just slide the switch in and secure it with adhesive.

Getting the wires to exit out the bottom may or may not be possible, depending on the shift knob you are working with. If the neck of your shift knob threads onto your shifter handle, and you want to keep the threads, you'll probably want to drill the side of the knob above the threads and exit the wires there.

The neck of my Momo knob wasn't threaded for installation on the shifter handle. Instead, it was designed to secure to the handle with supplied Allen screws, and I was able to use this to my advantage during the pushbutton mod.

I had already learned with a previous Momo knob this set screw arrangement isn't acceptable, because the knob continuously works itself loose, and it never really sits right on the handle, even when it's tight. That previous experience had led me to come up with a workaround. Specifically, I found that I could press a piece of ASTM pipe into the neck of the Momo, and then tap the ASTM to the correct thread for the handle. That way, I could thread the knob on just like the factory part.

This workaround turned out to be doubly important in modifying the new Momo. I hogged out a channel just large enough to accommodate the wires along one side of the knob's central cavity and recessed the wires there before installing and tapping the ASTM. This way, the wires would be coming directly out the bottom of the knob, and they'd be completely concealed once the knob was screwed into the boot.

Most Momo shifter boots are equipped with threaded collars that enable various Momo shift knobs like mine to be screwed into the top of the boot for a very clean appearance. Since I had routed the wires directly out the bottom of the knob, inside the perimeter of the collar, I was able to keep the wires completely hidden once everything was all buttoned up.

Routing the wires down to the REV solenoid on the transmission isn't any big deal. I just cut a hole in the outer shift boot (the one with the metal plate that secures with 4 bolts) to make a passage for the harness.
 
#6 ·
thanks so much TAZ; I also will probably make a custom switch, for the same reasons you did; the hurst knob is ok, they even make one with the correct shift pattern on it, but it may not be cosmetically acceptable. I am working not on a mustang, but a 53 studebaker with twin turbo stude engine and a viper T56 mated to it,(hence my interest in what you were doing) and the interior is going to be like a Hawk if you have any idea of what that is...The button part number is real helpful. I reckoned you did pretty much what you explained. LG makes a nice knob with a momentary for the vettes, but its a little pricey.It seems to be designed for some silly exhaust noise, but would be effective for my purpose. Right now one of my issues is the T56 from the 92-96 viper I have, the reverse lockout seems to be a mechanical one, and doesn't have the electromagnetic solenoid the later models have.I am looking into retrofitting the later model lockout; I for one think its worthwhile, because it really is possible to go from sixth down into reverse, especially if you're not driving the car every day- thanks- m weiss
 
#7 ·
Sounds like a GREAT project! Being a card-carrying AARP member, I certainly remember the Studebakers. The '53 2-door HT Commander is one of my all time favorite body styles.

I don't think changing the REV lockout over to the solenoid style will be any big deal, but you'll probably need to swap out the tail housing for one of the newer ones.

Best of luck with the project.

:thumb2:
 
#8 ·
Just did this. Put a switch in the boot bezel. I picked up some of those tiny momentary switches and was going to mount one under the left headlights switch but opted not to.
 
#10 ·
My preferred solution would still be a vehicle speed triggered release of the solenoid, in a way that it opens the solenoid for engagement of the reverse at speeds, let's say, below 3 mph. Using the speedo signal would probably be a bit unaccurate as it would not take into account the final drive ratio, but at those low speeds it would not really matter if the solenoid opens at 3, 5 or 7 mph, as long as it does NOT open at higher forward speeds. Such a device would work without any button.
However if I don't get such a solution to work, a switch button plus delay timer would be the second best solution...
 
#11 ·
Such a device exists. A friend of mine recently brought this little gizmo to my attention ...

T56 Reverse Solenoid Actuator

This controller wouldn't be a option for an older vehicle, but it should work fine for your car.
 
#16 ·
I am wondering if nobody else could build a device like GRC's.
I am not an elecronics d-i-y expert myself but I imagine it cannot be that hard... and the cost of producing those is probably in the range of a few bucks per piece only, so at $ 99 there is quite a profit margin in there... any soldering experts??
 
#17 ·
LOL It would cost more than a "few" bucks. The plastic hobby box would cost you that much. But parts would run you well under a hundred dollars, and there shouldn't be any rocket science involved in coming up with a circuit to duplicate this functionality. Here's one grossly oversimplified possibility.

The OSS is a Hall-effect sensor, right? You'd need to know the voltage vs. speed characteristics for that sensor. Specifically, what is its output voltage at 3 - 5 mph?

You could use that as the switching voltage for a circuit that energizes the primary side of a solid-state relay.

Then, you could connect an ignition-switched 12V source to the input of the relay's secondary side, and the lockout solenoid to the normally closed contact of the secondary.

Such a power circuit would deliver 12V to the lockout solenoid whenever the ignition was on and the OSS voltage was below the threshold required to energize the relay, i.e. below 3 - 5 mph. Once the OSS voltage exceeded the level necessary to close the relay, voltage at the output end of the normally closed relay would drop to zero, locking out reverse.

The one obvious problem with this simple circuit is that it isn't failsafe. By that, I mean the solenoid would remain energized all the time if the relay craps out. That's unacceptable from a controls standpoint, so you'd need some watchdog circuitry in addition to what's outlined above.
 
#19 ·
No argument there. As I said, the parts would run well under $100. By the same token, making the them for "significantly less than $100" is not the same as knocking them out for "a few bucks per piece."

With respect to the level of complexity and the parts complement, I've built similar gizmos in the past, and I'd estimate the raw parts cost would be in the neighborhood of $20 - $25 for each unit in small quantities (500 or so). To that, you'd need to add assembly labor costs, documentation costs, and packaging, not to mention an amortized cost for your R&D time.

In small lots, someone might end up netting perhaps $50, maybe even $60 profit on each unit. Certainly "enough margin for the seller," but nowhere near enough to cover that vacation property on Maui. LOL
 
#25 · (Edited)
I know this is a dead thread, but i don't find that to be a "solution" because you still have to activate a switch at some point. I just bought an 03 zinc mach today and it doesn't have any lockout. I figured this out when I tried fourth to fifth and was met a nasty grinding sound, "well thats reverse then eh?" were my thoughts lol. There has to be a better way to do this, anyone figured that out since this was active?
 
#24 ·
Guys I think the easiest and cleanest solution is simply cutting a coil and a half off the spring in the reverse lockout housing. This is what I did with mine and the reverse now works just like the TR-3650. No goofy switches or buttons, extra wiring or hacking into the wiring loom.
 
#29 ·
My car doesn't have the lockout though, I imagine the guy that owned the vehicle before me took the solenoid off and tapped the hole and put a plug in it like some people in this thread had suggested. An auto car has a lockout type mechanism in the shifter itself right? Well never mind I was just thinking, I suppose the button on the shifter is how that lockout works lol. I thought I had an idea.

I wouldn't think it'd be impossible to get it to work like it's suppose to, without having to press a button(with a timer), or removing the solenoid altogether.
 
#32 ·
What is the problem with just installing a spring that provides enough pressure for your liking? Fairly simple process.
 
#34 ·
The reverse lockout solenoid provides resistance by using a heavy duty spring that pushes against the side of the shifter as you shove it towards reverse. The electrical part of the solenoid reduces that spring pressure so it is easy to get the shifter into reverse. Without the solenoid activated by a 12v source it is difficult to overcome the spring pressure. To make the T-56 reverse work like a normal transmission all a person has to do is modify the large spring that provides resistance in the lockout housing pictured below. Since yours is providing little resistance we have to assume it either does not exist or has been modified to provide too little resistance. Simply put a new spring in that provides the level of resistance that you prefer. If you like to slam 5th, you'll probably want more resistance. If you have girl arms you will probably want less resistance. You can purchase an aftermarket spring or replace the factory one and start by cutting off half a coil at a time until you achieve the resistance you want. 1.5 coils is equivalent to a stock TR-3650. You may want to remove 1 coil or less if you hit 5th hard.

Gas Cylinder Auto part Nut Machine
 
#35 ·
The reverse lockout solenoid provides resistance by using a heavy duty spring that pushes against the side of the shifter as you shove it towards reverse. The electrical part of the solenoid reduces that spring pressure so it is easy to get the shifter into reverse. Without the solenoid activated by a 12v source it is difficult to overcome the spring pressure. To make the T-56 reverse work like a normal transmission all a person has to do is modify the large spring that provides resistance in the lockout housing pictured below. Since yours is providing little resistance we have to assume it either does not exist or has been modified to provide too little resistance. Simply put a new spring in that provides the level of resistance that you prefer. If you like to slam 5th, you'll probably want more resistance. If you have girl arms you will probably want less resistance. You can purchase an aftermarket spring or replace the factory one and start by cutting off half a coil at a time until you achieve the resistance you want. 1.5 coils is equivalent to a stock TR-3650. You may want to remove 1 coil or less if you hit 5th hard.

View attachment 76277
Well I'll look into that for sure then. Thanks for the info.
 
#36 ·
Careful guys......D&D transmission (where I got my T56 transmission) told me guys have damaged their trannies by forcing the lever into gear - also there was one guy that had cut a coil off, but the issue is there is something inside that wears out....I can't remember the name of the part, but inside there is a part that you wear down if you force it in.

Problem: To get the effort down to where you won't damage the trans, you have to cut so much coil off of it that you lose the lockout effect. Call D&D and ask them before you try this because you will damage the transmission. I bought a kit from a company that makes an after market controller. I forget the name but saw this post I figured I would add it in. It's either Samco or Samoco I forget. If you pm me I will look for the receipt - it's around here somewhere.
 
#37 ·
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top