A-500 transmission OD and LU controls.

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AJ/FormS said:
Well I think that settles it; 2400 in a warm 5.9,(say a 220ish cam with matching compression), could easily be 200. Thx TB
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It was only about an inch or less of gas pedal, but I don't know what it takes to push a 73 Dart at 120.
Considering the old 318 would about be flat out wide open for 120 I would have to guess about 180 maybe.
 
Sounds about right
120=4265 rpm with 2.76s so the old teener would have crossed the torque peak a long time ago; probably at the 100mph mark.It might have been making as much as 250 ftlbs there (WOT). I'm satisfied.
 
From what I recall, LockUp is only possible in 3rd or 4th gear, regardless of the manual switch.
 
OK, so I'm working on this again. I got my vacuum switches from the TCI kit (TCI CMP3766B TCI Replacement Vacuum Switches CMP3766B) and Honeywell 76074 (76074 Standard Pressure Switches - Honeywell) adjustable 20 to 60psi pressure switches (I got a sweet deal so I hope they'll work). Right now I'll have a pressure switch and a vacuum switch controlling each transmission solenoid. I'm a long way off of actually trying this since the adjustment and commissioning of the system won't happen till spring.

My question surrounds the governor pressure port. In the transmission manual it states 1 psi per mph, and I get that, but I can't wrap my head around how this cannot be affected by the gear ratio somehow. I will preset my switches at about 45 and 50 psi to start, but I can't help but think what you would get for shift speeds with 2.45 gears would be significantly different than what I would get with 3.23s or 4.10s. I know I'll prove this all out when the transmission is in the car and I am testing, but I am obsessed with this right now and just thinking out loud (or at least out loud on the keyboard).

anyone have any thoughts on this?

Cley
 
The governors are supposed to be matched to the rear gears to keep the system operating inside certain parameters. There are several different flyweights and springs available, and the cross pin will accept up to four E-clips. Then you fine-tune the line pressure, and throttle pressures, to get everything working the way you like it. And finally, if you like playing, you can just machine weight off the governor weight yourself and swap in springs to your hears content, but be advised that pulling the doggone extension housing off everytime gets old in a hurry,lol.
Your thinking is correct; if you install a governor that originally came from a 2.76 equipped car , into your 3.91 geared car, the driveshaft speed will now be 41 % faster,and so the upshift speed will be ,bam-bam! very early. So a lighter governor weight will be needed to get you into the ballpark. Then you fine tune with springs. and then perhaps a little line pressure.
In practice, the line-pressure is boosted when you install a shift kit. In which case, all the tuning has to be done with weights and springs and E-clips .......and throttle pressure.
Governor Kits - A&A Transmissions
http://www.hotrod.com/articles/mopp-0208-increasing-shift-speeds-on-the-727-torqueflite/
 
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If the trans in not yet installed, I'd pull the governor now and record which weight and spring are currently in it, So you can have a better idea of what to do later.
If that trans is out of a Dakota, the governor may already be set up for 3.91s
 
Well then it may be set up for something greater than 3.91s,maybe making it a winner for you; cuz I think there are only about 3 plugs and 3 springs (That I have seen),that cover the whole range of rear gears, cuz the fine-tuning is done with pressure balancing.
 
Well I finally got to drive it very briefly on Saturday. It still needs a bit of commissioning as it doesn’t hit overdrive till about 70 mph and I’m not sure about lock up. I will say though, with 245/60-15 tires and 3.23 gears it ran about 2800 rpm at 75 mph before and once that OD/LU kicked in it was about 2000 rpm. So that right there is a win for me.

When I finally got it wired up, I used a single shut off switch to the 2 coils and 1 vacuum switch to disable both OD and LU on acceleration. I still may wire in some “timed off” relays to avoid hunting between OD on and off. It happened a couple times on that first run that I tried automatically shifting to overdrive but once I get my pressures set where I want OD to engage it may not be an issue. I still need to look at making some type of enclosure since I hate the way it looks under the hood and if I add relays etc, that’s just more clutter I need to clean up and hide.
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I am looking forward to driving it more and getting it tuned just right because I think it will really help highway drivability. The newly rebuilt Trans with the shift kit and higher stall convertor is really nice even when used as a 3 speed!

Cley
 
LOL!! I did not know you were supposed to have OD before lockup. I "modded" the trans in the White Whale III (00 Dodge 2500) which evidently had a sensor problem, still don't know. It would not activate manually without the computer having some resistance to emulate the solenoids. So I just wired two old junk relays to the ECU so it "thinks" it is switching the solenoids

Been a couple of times I've rolled up to a light and took a second to figure why the engine quit!!! LOL
 
TrailBeast said:
Overcomplicated.
The governor pressure in lbs is real close to road speed in mph, so normally off adjustable pressure switches can be used to activate OD and LU.
This way there is no need for an electronic speed sensor, as the governor supplies speed sensing in psi.
NOS fuel safety cutoff switches work great for this, as they are designed to disable the NOS if there is insufficient fuel pressure. (so normally off, but contact when the pressure is high enough)
Plumbed into the governor port and set at different pressures gives you an adjustable speed range where OD and LU engage.

Then a normally on adjustable vacuum switch can be used to kickdown on heavier throttle by breaking the ground for the relay that controls the respective solenoids in the trans when intake vacuum drops below your set range.
If you build the system with power to the trans whenever the ignition is on it's easy to use ground switching for engaging disengaging OD and LU.

My own 42RH is set to go into OD at about 55mph, and LU at 70 completely automatic, but if I turn the ground off to one or the other of the control solenoids with the switches on my shifter it disables it.
If I have the OD switch on inside the car the trans automatically goes into OD at 55mph, but if the lockup switch is off then LU will not come on.
If I have the OD switch off and the LU switch on the trans will skip OD and then LU at 70mph in 3rd.
This means I can run it in 3rd with lockup, OD with lockup or OD without LU but I have never seen any real use for doing it.

Oh, and I plumbed those two pressure switches up to the back of my intake on a mounting bracket so those speed adjustments can be done from under the hood instead of under the car like some do.
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I would love to see some pictures and part # of your system Trail Beast.
 
So I finally got some seat time with my OD and LU controls in action. I am super happy with the results. There is still some more tweaking the pressure switches to be done because OD and LU engage at almost the same time.
Fortunately there is no need for the timing relays as there is enough deadband in these pressure switches that fluttering or hunting between engage/disengage won't happen. It currently engages about 50 mph and disengages about 45 mph. I'l
Set the LU at 60 mph to start.
It shifts fully automatic up and down and the vacuum switch kicks it off when you put your foot into it. I can't imagine how another system could improve upon what I have here.
The diagram below shows my final schematic. You can see the fuse, switch then the vacuum switch which all kill power to the entire control system. Then PS1 is the OD pressure switch and OD is the solenoid in the transmission. Similarly PS2 is the LU pressure switch and LU is the solenoid in the transmission.
I'll post a video of the tach as it shifts once I get it all fine tuned. I am so happy this turned out as good as it did!
Cley
SIMPLE OD AND LU(3).PNG
 
Update on my TCI vacuum switch. It appears that the contacts are burned up on my vacuum switch. I have to bust it apart to confirm that, but I know it's the vacuum switch causing the problem where it won't kick into OD, or not go back into OD after the vacuum switch kicks it out. I jumpered the contacts on the switch and it engaged OD/LU as normal.

I may need an interposing relay to remove the load from the switch contacts but I don't really want the added complexity if the relay. Any suggestions of a switch to use that could carry more load? The TCI switch needs between 8 and 10" of vacuum to close the contacts and that seemed about right.

Cley
 
Definitely need a relay or a different switch. The TCI switch was about perfect for setpoint right out of the package so I think i'll stick with that and a relay. Now If I could only find the spare vacuum switch I bought. My garage is such a messy shithole right now.

Cley
 
Nice work man.
What a trip it is to have it shift again after third and it took about 6 mos before I got used to it.
Just FYI my vacuum switch interrupts the ground for the relays instead of interrupting the pressure switch.
That way the vac switch only has the load of the relay switching through it.
 
I bet they are stronger than you think. I was experimenting with the "White Whale III" (01 Dodge 2500 2wd 5.9 gas) I cut the computer wires to the solenoids and wired old relay coils to the computer to keep it happy, then fire the OD and lockup with toggles

You can't slip that thing. I towed the infamous junk pickup back over hill and dale, and at one stoplight coming off the freeway forgot to unlock. Had the front wheels skidding trying to stop it before I figured out what dummy had done LOL. It also would not slip under heavy pulling up hills when locked
 
I never put relays in it but I will now because relays are cheaper to replace than the switches I am using and are rated for lots of amps. Even if I don't need to have a kickdown system (not using one right now), I love the way it knocks the OD/LU out and revs up to 2600 and pulls like crazy when passing someone on the highway. Then the OD/LU kicks back in and it's smooth cruising again! I think of it like a dual personality for the car.

Cley
 
Being I use a simple manual switch like mentioned earlier in the topic, I can tell that if I flip the switch 'softly', the contacts inside will probably arc a bit and the switch sometimes doesn't register its new position.

When I really flick the switch it registers all the time consistently. The firmer 'flick' prevents arcing and burning-in of the contacts I think.

So yes a relay is definitly adviced.
 
I was giving my Man Cave a much needed cleaning this weekend and I found the pieces I needed to get the vacuum kick down reinstalled. I am looking forward to having that functioning again. I think I'll use 2 relays because relays are cheaper and easier to replace, and more readily available than either my pressure switches or my vacuum switch.

Cley
 
89on35s said:
I was giving my Man Cave a much needed cleaning this weekend and I found the pieces I needed to get the vacuum kick down reinstalled. I am looking forward to having that functioning again. I think I'll use 2 relays because relays are cheaper and easier to replace, and more readily available than either my pressure switches or my vacuum switch.

Cley
Click to expand...

Yep, those switches ain't cheap.:D
Anything to protect them can only be a good thing.
 
It's been a while but I thought I should update this thread again. Last summer I installed relays to switch the solenoids in the trans (OD and LU) and wired my vacuum kick down switch to the negative side of both relays and it worked very well until now. I had another TCI vacuum switch fail on me. I guess I'm on the hunt for a different kick down switch. Maybe a nitrous WOT switch? I am also thinking about using the line lock button on my shifter but I'd have to wire it so it worked as a line lock button when the OD switch is off and a kick down switch when it is on. Itll just take a coue more relays!

Cley
 
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