When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
You don't want to do it with the neutral safety switch.
You want to do it with the internal pressure manifold switch.
If you do this, you will need to do it with fixed line pressure.
Using the manifold switch, there are three outputs...A,B,C (N,P,R pin locations respectively on the round case connector)
We will call your relays 1 & 2
Use an external wire harness connector (parts stores sell repair kit connectors)
connect pressure manifold output A & B (N&P) to the trigger side of relay 1
connect pressure manifold output C (R) to the trigger side of relay 2
The relays need to be switched to ground...not power
Relay 1 connect to pin A on the round connector (1-2 shift solenoid)
Relay 2 connect to pin B on the round connector (2-3 shift solenoid)
Make sure pin E on the round connector has key on 12 v
Pin S on the round case connector is for TCC lockup...switched ground...flip the switch whenever you want lockup.
That should cover everything you need to make this work...but with fixed line pressure you risk hurting things if you don't properly control reverse boost pressure, and if you don't properly size your separator plate feed holes.
This
So I guess theres no delay on this switch or not enough to make any difference.
It is also more accurate since it depends on the valvebody not a potentially sloppy position switch.
I'm helping a friend doing a low vacuum carb engine swap and we're not sure the PCM will still run the trans properly with no vacuum.
We were looking at dial type controls and vacuum modulator conversions, I dont think he wants to tear down beyond the front pump or valvebody.
I bet this got some lulz from the knowledgeable ones. I'm convinced it would work, just not how well.
I appreciate the info.
the way you described gives you no A solenoid in reverse and activates A in D2 where it is not required
and if you use the normal closed 87A pin (switch off=relay on) it deactivates A in multiple gears.
Last edited by Rusted40; Feb 14, 2019 at 05:29 PM.
the way you described gives you no A solenoid in reverseWRONG and activates A in D2 where it is not required WRONG again
and if you use the normal closed 87A pin (switch off=relay on) it deactivates A in multiple gears.
I'm guessing you lined up the charts and saw they didn't match...even tho one chart is labeled PRN1234 and the other is labeled PRN4321...this really isn't that hard.
So...If you can't read a simple on/off switch and solenoid chart and match them up...I'm not sure it's my job to spoon feed for you. But for the sake of anyone else that finds this thread...Here goes.
Attached is the excel grid I made up in about 1.5 minutes. It really is that simple. You can see pressure switch output A&B highlighted in blue. If EITHER column AorB shows LOW (highlighted in green to make it even easier) then you can see the solenoid A will also show ON. Simple
If pressure switch output C (highlighted in orange) shows LOW (in green again) then you can see shift solenoid B is ON.
Everything matches up just like they are supposed to.
If you still think that's wrong and/or can't figure it out...then I can't be of much more help. I have personally setup multiple customer vehicles with this setup and know for a fact that it works perfectly. No issues.
so you're using low (=switch off) to assume a normally closed 87A pin to ground the solenoid correct?
this means hi (=switch +12v) activates the relay, thus opening 87A and cancelling the ground to the solenoid.
either wire thats hi can kill the signal to the solenoid if those 2 wires are on the same relay.
I think maybe theres something lost in translation or you aren't really sure how relays work.
You don't even actually need a relay...you can tie the pressure manifold wires straight to the solenoid without using the relay...I just prefer to use a relay as a means of safety between the pressure switch and solenoid.
I've wired it up this way inside the pan of an 80e and it worked fine for a whole race season...Just had one power wire going to the case connector and that was it.
You're the one that is asking for help and I've made it clear that this method works flawlessly. If you'd like to think of a different way, be my guest.
I've been watching this thread, it's a bit confusing not knowing what it is that is trying to be accomplished here.
I've used the TransGo instructions to diagnose a truck that I was sure had bad wiring.
I did what the picture shows and it went down the road like a manual valve body.
Compared to everything above this seems too easy to connect 12 volts to one wire and ground two and drive it. Ground one more to lock the tcc.
Why would you think that the PCM won't shift the trans correctly due to low vacuum?
The PCMs I have tuned shift according to throttle position, not according to MAP values. Granted I have no experience with pre-'98 PCMs.
Why not document more about the engine and the PCM instead of assuming something so drastic is needed.
I've never seen a ground referred to as 0 volts....
Interesting how these switches work.
It's a matching COE rollback for hauling the one on the right.
He wants manual control and we're still looking at options for controlling line pressure.
If this is PWM regulated, how are people using rheostats to control it without a computer?
Yes. Your drawing should have the pins from the connector (N,P,R) going to the relay triggers (A,C,B respectively)
Pin E gets 12v key on
Toggle a ground to pin S
Now...you've got the relays to work...Next job is to figure out how to deal with the MASSIVE pressure you will have in reverse.
Since you won't be using the PCS to control line pressure...you'll have fixed line pressure. If you have a stock boost valve and pressure regulator spring (assuming both are in good condition and not worn out) you'll have probably 170 ish PSI by 1200 rpm in all gears...and well over 300 psi in reverse...I've seen as high as 450 psi before. Simply stated...you're REALLY risking breaking ****, or at the very least, accelerating wear, with that high of pressure in reverse.
I take care of the reverse line pressure by making internal modifications to the pump. I haven't seen you make any mention of tearing into this trans...so I can only say to you...godspeed
I've seen over 800 psi in a 60,000 mile 80E with a worn boost valve. It broke the reverse servo. It sucks having no reverse.
Sometimes you need to do the right thing. I don't know who the HE is you are referring to but you need to talk him into an aftermarket transmission controller. He's not going to be happy the first time that rig needs to be towed, and I'm guessing that won't be long after it's on the road.
I work the internals/pump to handle reverse pressure and keep it from breaking ****. Since he has made no mention of rebuilding any part of the trans...and the relay section was apparently hard enough to understand, I'm not going to get into what I do internally to the trans.
I'll agree Jays, based on what I'm seeing here...I think the best bet for OP would be an aftermarket controller
Not sure what you are trying to accomplish, but simple to use a pigtail and bridge some wires and have
man. You can get a Transgo mod valve kit that installs in the trans that reduces pressure, I have used a couple.
Why not get a controller for the trans, like a Compushift, it has a man. control option.
From looking at the vehs., there is money out there, lol.
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Slideshow: From wobbling harmonic balancers to failed EBCMs, these are the issues that define long-term C5 ownership and what repairs typically involve.
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Slideshow: A one-off sports car that looks like a vintage Italian exotic-but hides a C6 Corvette underneath-just sold for the price of a new mid-engine Corvette.
