46rh od/lu not disengaging

[mbaird]

my 46rh is not dropping out of OD/LU when my speed drops below the preset engagement mph . Both will kick out if I accelerate and the vacuum drops . Everything engages as designed but it won’t disengage automatically. Does the line pressure not drop as I slow down ?
I have it set up with 1 46psi pressure switch , 2 timer delays , a vacuum switch set to 8hg and a master power switch.

I will try to post a schematic of my wiring.

Any thoughts ?

 

[mbaird]

 

[Dana67Dart]

Is the box sealed? If there are vacuum or pressure switches they MIGHT need atmospheric pressure to allow disengagement?

Just spit balling. easy to test leave the cover off and test drive

 

[mbaird]

Is the box sealed? If there are vacuum or pressure switches they MIGHT need atmospheric pressure to allow disengagement?

Just spit balling. easy to test leave the cover off and test drive

It’s sealed enough to prevent want intrusion but not airtight.
It works as designed for engagement and kicks out with enough throttle pressure so the vacuum switch doesn’t seem to be the issue . It just won’t disengage when I slow down unless I turn the master power switch off . And sometimes I forget … it reminds me around 10 mph though. Lol

 

[Dana67Dart]

It just won’t disengage when I slow down unless I turn the master power switch off

what is supposed to tell the lockup to disengage?

 

[mbaird]

what is supposed to tell the lockup to disengage?

I assumed the line pressure drops as you go slower . Line pressure goes up 1 psi per mph ( depending on gear ratio and tire size ) so when it hits 46 psi or approximately 46 mph the 46 psi pressure switch initiates the OD/LU engagement. I use 2 timers set at 10 and 15 seconds to stagger the OD and LU functions . Not sure if line pressure also drops the same way as you slow down but assume it does.

 

[Dana67Dart]

If I understand this correctly....


The trans pressure switch says the trans is running and at the correct pressure to allow OD and Lockup
The carb vacuum also has to be in the correct vacuum range to allow OD and lockup.

if BOTH those circumstances are met than there is a ground source for OD relay timer to be energized and that closes the NO contact at 8-12 and that provides a ground source to the transmission connector at OD

When the OD relay / timer energizes the NO contact at 5-9 closes and provides 12V to the LU relay / timer which then energizes and closes the NO 8-12 contacts on the LU relay timer and provides a ground source to the transmission connector at LU.

now you have OD and Lockup.

if the carb vacuum signal goes above/below (based on your perspective) a set point the vacuum switch opens and the OD relay timer should de-energize opening the 8-12 NO and the 5-9 NO contacts ALSO de-energizing the LU relay timer opening the 8-12 NO contacts and the trans SHOULD not be in OD or LU

ALSO the same happens if the trans pressure switch opens due to its pressure set point.

Lastly the power switch kills power to everything and OD and LU are instantly de-energized.

The entire system passes my logic tests so it must be the vacuum or pressure sources not acting the way you expect. Or faulty components.

what are you using for a vacuum source?
what are you using for a trans pressure source?

 

[mbaird]

If I understand this correctly....


The trans pressure switch says the trans is running and at the correct pressure to allow OD and Lockup
The carb vacuum also has to be in the correct vacuum range to allow OD and lockup.

if BOTH those circumstances are met than there is a ground source for OD relay timer to be energized and that closes the NO contact at 8-12 and that provides a ground source to the transmission connector at OD

When the OD relay / timer energizes the NO contact at 5-9 closes and provides 12V to the LU relay / timer which then energizes and closes the NO 8-12 contacts on the LU relay timer and provides a ground source to the transmission connector at LU.

now you have OD and Lockup.

if the carb vacuum signal goes above/below (based on your perspective) a set point the vacuum switch opens and the OD relay timer should de-energize opening the 8-12 NO and the 5-9 NO contacts ALSO de-energizing the LU relay timer opening the 8-12 NO contacts and the trans SHOULD not be in OD or LU

ALSO the same happens if the trans pressure switch opens due to its pressure set point.

Lastly the power switch kills power to everything and OD and LU are instantly de-energized.

The entire system passes my logic tests so it must be the vacuum or pressure sources not acting the way you expect. Or faulty components.

what are you using for a vacuum source?
what are you using for a trans pressure source?

Using manifold vacuum port and line pressure test port on passenger side of transmission.

 

[autopar3000]

I'm not sure you can say for sure that 46 psi is 46 mph. There are too many other variables, like your rear gear, torque converter stall, tolerances in the transmission itself, etc.

Your switches might be defective, or the pressure might not be getting low enough to open the circuit.

I used to have a similar setup, but my pressure switches were adjustable. It allowed me to dial in the OD and LU points exactly where I wanted them, and it didn't require any kind of timer.

I did not have anything vacuum related that would cause the OD or LU to disengage, I felt like it wasn't really necessary for me.

I would suggest you look into getting a couple of adjustable pressure switches. I can't remember exactly what I used, but I just found some that operate between 25 and 50 psi. For example, Dwyer A6-653221. The Dwyer A6-753221 operates between 51 and 90 psi.

 

[mbaird]

I wonder if my delay timers delay in the disconnect mode as well for the set amount of time ? Maybe I will try adjusting them to 5 seconds for O/D and 7 for L/U to see what happens …..

 

[Dana67Dart]

I would think that it would be better to release LU before OD.

I'm not sure that a vacume signal is the best indicator of closed throttle.

 

[Demonic]

Better check the delay timer action. Is this a new installation?

 

[mbaird]

yes, new install.
Gotta say it works great! If only it would just drop out when my speed drops. It’s just a matter of time before I forget to turn it off when I come to a stop.

 

[mbaird]

Maybe I will install a NO brake switch inline with the master power switch?

 

[Dana67Dart]

Is your setup designed to disengage at a specific speed due to pressure?

Thats why computers control things.

I assume you would want the lockup to disengage upon near full throttle, and the OD to disengage at full throttle.

Climbing a hill and passing other cars.

 

[mbaird]

Is your setup designed to disengage at a specific speed due to pressure?

Thats why computers control things.

I assume you would want the lockup to disengage upon near full throttle, and the OD to disengage at full throttle.

Climbing a hill and passing other cars.

They disengage simultaneously with about 1/3 throttle at hiway speeds. The vacuum switch cuts the power then reingage when the vacuum goes bacck to full hg + the time delay

 

[Dana67Dart]

Have you put a vacume gauge in the cir to see what is really happening

 

[str12-340]

I think I'll stick with this . My brain is the computer and after 3 years and 18,000 miles I really don't even consciously think about hitting the switches.

 

[autopar3000]

I don't think the issue is the vacuum switch, it seems to be cutting power when its supposed to.

I think it's the hydraulic pressure switches. They are supposed to close the circuit at a set pressure then open the circuit once it drops below a certain point. For example, close the circuit at 45 psi then open it again once the pressure gets down to 40 psi. But there are tons of different options on the market, so it could be the switches won't open the circuit until the pressure gets below the transmission's lowest possible pressure (or they're defective). When you hit the switch it cuts power and the normally open switch goes back to its normally open state.

 

[autopar3000]

Maybe I will install a NO brake switch inline with the master power switch?

You could do that and I'm sure it will work, but it feels like a band-aid. I really think you should get a couple of adjustable pressure switches and get rid of that wonky timer setup. You can then dial in your OD and LU points exactly where you want them.

That setup worked great for me until I sold it to a friend. He's still using it in his Barracuda. (I went to factory Magnum EFI and computer controlled so I didn't need the analog setup anymore.) It would be even better with the vacuum kickdown you have.

 

[mbaird]

Have you put a vacume gauge in the cir to see what is really happening

Yep … have a vacuum gauge .
I think the vacuum aspect of it is working fine . Of course on deceleration the vacuum climbs but if I blip the throttle both OD and LU disengage.

 

[mbaird]

You could do that and I'm sure it will work, but it feels like a band-aid. I really think you should get a couple of adjustable pressure switches and get rid of that wonky timer setup. You can then dial in your OD and LU points exactly where you want them.

That setup worked great for me until I sold it to a friend. He's still using it in his Barracuda. (I went to factory Magnum EFI and computer controlled so I didn't need the analog setup anymore.) It would be even better with the vacuum kickdown you have.

The timers help prevent the OD from phasing in and out when driving close to the engagement speed .

 

[autopar3000]

The timers help prevent the OD from phasing in and out when driving close to the engagement speed .

With properly functioning / properly calibrated pressure switches the OD disengagement speed is 5 - 7 mph below the engagement speed.

 

[JDMopar]

@autopar3000 How did you set the pressure switches up? Come out of the pressure port to a T fitting with one on each side at the trans, or plumb them up to the firewall where you could get to them easier to adjust them?

 

[mbaird]

@autopar3000 How did you set the pressure switches up? Come out of the pressure port to a T fitting with one on each side at the trans, or plumb them up to the firewall where you could get to them easier to adjust them?

I ran a line to the engine bay and used a small box to house everything which is mounted on inner fender .