If you don't have the switch on the brake pedal it will not unlock
CK5
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torque converter lockup in any gear
- Thread starter anwat
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- 700r4 lockup torque converter
yes mine automatically locks in 4th @45 mph. Unlocks when down shifting from 4th or braking, with the switch off. I try not to let the trans shift with torque converter locked, with switch, only use when I select 3rd or 2nd manually with shift lever
Here's one of a few standard 80's internal wiring diagrams. With the 4-3 shift solenoid in place, the TCC unlocks when the shift out of overdrive happens.
I see diagrams on 700R4.com (Bowtie Overdrives) that show how they want you to wire your truck, but I don't see any diagrams of how they have their transmissions wired internally. If somebody "spent a lot of money" to have the wiring done a certain way, that implies the internals are non-stock.
I see diagrams on 700R4.com (Bowtie Overdrives) that show how they want you to wire your truck, but I don't see any diagrams of how they have their transmissions wired internally. If somebody "spent a lot of money" to have the wiring done a certain way, that implies the internals are non-stock.
So, once I got in there and followed the wires, I think I understand what's happening. The power for the switch is coming from the A pin. I'm no electrician, but I'll try to draw it out. From what I think you're saying above, just because the solenoid has power doesn't necessarily mean it locks, there are additional requirements that need to be met. So, the way this is wired up, once the D pin gets power, the indicator lamp will light. But it may not be locked, it just means the D pin is powered. This isn't the way the schematic Wes Harden mentioned has it wired. I'm wondering if this setup would cause the light to be lit if the switch was off and the tcc actually unlocked coming out of 4th, like it should. In that case, the trans is working right, it's the light that is indicating it's still locked in third and second when in fact it's not locked, it's just energized. Or am I still way off?
I recall that there is/was a way to setup an auto trans and TCC so that you can lock it up in low gear for hill descent at low speed. Keeps you from having to use the brake which can lead to sliding especially on a muddy hill. (This was way before hill descent control was offered from the factory and I think at least some of those factory systems are ABS based not tranny/TCC based) Can that be what the OP's switch is for? For what its worth, how do you setup a transmission for hill descent and can it be done on the modern trans like a 4L-80E?
If that is how your truck is wired. It's wrong, at least external. A terminal 1 wire. Hot with key on, thru the cruise control style brake switch. The brake switch needs a normally closed 2nd circuit, for lock up.
So fused key hot to brake switch normally closed. From brake switch to terminal A. Ground is internal to trans.
Forget about D for the moment, disconnect D.
So fused key hot to brake switch normally closed. From brake switch to terminal A. Ground is internal to trans.
Forget about D for the moment, disconnect D.
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Yeah, your diagram can't be right. The lamp probably is wired to the D terminal. That's a factory output that enables EGR or such. If the TCC is locked, that indicates "cruising". Typically B is wired only through the brake switch or always hot and A is through both brake and vacuum switches. So B is sort of your "always be locked in 4th gear" terminal.
That's what I thought...I'm off to try to find a brake switch and I'll get it wired the way the schematic shows, but skip D. Thanks for the help I'll post up with the results.
From what I've been reading here, I don't think you can lock in low gear, and it doesn't sound like a good idea, since if you stalled it out, you'd need your brakes to stop.
Nope, that's how it's wired. I had the neighbor over last night who is a little more electrically inclined than me, and asked him to look at the circuit. He drew the same thing. It looks like it's taking the power from the A terminal and putting a switch in it, then right back to the D terminal. No other switches or connections along the way. The light is on the switched side, right after the switch. I'll get it wired correctly today and see what happens.
If that's how it's wired externally, then the internal wiring can't match what I posted above. The fuse would pop as soon as the solenoid engages (if your toggle switch is on). It will be hard to make any progress without knowing what's inside the trans. Google searches turn up some diagrams that seem to match your description, but I can't find anything showing the internal wiring to match it:
The answer may be here: http://www.700r4.com/tech/tcc/internal_install/700r4.shtml
If you study the pictures, it looks like D goes straight to the solenoid and A goes through the 4th pressure switch to the solenoid. So yeah, putting power to D will give "manual lock", but how that works depends on which valve body you have.
But why wouldn't they make their wiring compatible with stock wiring?
If you study the pictures, it looks like D goes straight to the solenoid and A goes through the 4th pressure switch to the solenoid. So yeah, putting power to D will give "manual lock", but how that works depends on which valve body you have.
But why wouldn't they make their wiring compatible with stock wiring?
Point taken. I should know what's going on in the pan, anyway, so it looks like the pan will come off. I had to fab up a mount for the brake switch, I'll get that in and wired, then drop the pan and post up what I find. I'm thinking something may be amiss due to the fact that there was no brake switch installed, and every diagram I've seen says there should be one. Thank you guys for the help!
I just found this also: http://www.700r4.com/tech/tcc/brake_install/diagram.shtml. Minus the brake switch, I think this is the same way mine is wired. Now I'm so confused I've got to drop the pan and just wire the whole thing correctly. At least I can figure out which valve body is there.
Normal is without 2nd and 3rd, the other diagram show switch for 2nd and 3rd lock up. Kit with towing option is the way my system is wired
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The towing option is how mine is set up also, it appears to be unmolested from Bowtie's original wiring, since the wires are actually soldered to the case connector. So it appears I'll go with the BTO way of setting up the lockup since that's how the internals are set up, plus I only have an A and a D pin to wire to. I went and bought a cruise control switch, and then once I dug out the wires under the dash, found out the brake switch in there has two sets of terminals, one is open with the pedal pressed, the other closed. So I can just wire it through the existing terminals. I guess I'll have a bracket and switch for the next K5 I buy.
I got rid of the light, since it doesn't really indicate lockup anyway, only power to the solenoid. It's now wired exactly like the diagram above:
Which is how Mr. Harden's is wired from what I understand. The 4th gear switch has two terminals on it, both positive. I'm guessing the switch grounds through the case. I drove it up and down, and it shifts into 4th, and almost immediately it locks up. It almost seems like it shifts too early, I'm only doing about 40. But more importantly, as I slow down, it unlocks before I come to a stop, even if I don't press on the brake. I can't tell if it unlocks when i come out of 4th, but I would assume so. As of now, then, I have it running like a stock 700. When the rain stops, I go hook up the D pin and see what happens. I did notice the 4th gear switch is different in there..it's got two terminals on it.
Info only, it looks like the deal with two wires on the A terminal was just the keyed hot, and then it was using that current right from the terminal to go to the D terminal. That may have been why it wouldn't unlock, the D terminal was getting power anytime the A terminal got power. Not much is more annoying than someone using black wire for a hot, and changing wire colors in the middle of a circuit. Makes things very difficult.
I think it's all good now, hopefully the switch to the D pin will work as planned, and we'll be in business.
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Beautiful! The switch works, it will lock in 2nd and 3rd. Unlocks as soon as the switch is off. Won't need it in 4th, since it seems to lock up as soon as it shifts. What controls that 4th gear lockup, is it able to be modified? Is it a setting in the 4th gear switch, or based on fluid pressure? I don't have any type of computer controls, so it's got to be internal with the trans, I'm just wondering if I can modify something so it will wait until I pick up a bit more speed in 4th to lockup. Or do I need to make it hold 3rd a bit longer?
TV cable adjustment, the spring in at the Tv spool in valve body and road speed. I'm not 100% sure. Someone will chime in with a more definitive answer.
Glad you got working, the way was wasn't doing your trans any good
Glad you got working, the way was wasn't doing your trans any good
No, in stock apps, engine load was always a factor in the lockup, whether through ECM programming or the vacuum switch.
The Bowtie Overdrive setup is a 3rd-party setup, not a stock configuration. It's designed to make a 700 work in *whatever* vehicle, so it's not going to be the same as a GM factory install. I would say that in general, you want it locked in 4th gear. This trans doesn't flow a ton of fluid to the cooler in 4th gear and an unlocked converter can make it heat up fast. So while it's OK to run unlocked in 4th for several seconds at a time (climbing a hill, etc), there isn't a simple device that monitors this time or monitors the temp.
If you want to adjust the shift points, look at lighter governor weights. You can grind what you have or find a factory Camaro governor. That might work for you or could add small weights (Governor is easy to pull with trans in truck). First, be sure you have the gears for your tire size and setup of the truck. I'm sure you've looked up the proper TV setup procedure and done it, but you can get a little higher shifts by going a click tighter (if it doesn't just set back when you go WOT).
I think, all things considered, Imma just leave it alone for now. The TV took me a while to set up, and I even used a gauge, so I think it's probably where is should be. Maybe I just need to learn to like where it shifts. Part of it is I'm not used to the low rpms on a big block, I've always had a 350 so I always feel like the engine needs to be running faster.
I think I understand why I kept having temperature issues on my last few trips. I was in 2nd and 3rd most of the time, and wasn't using the lockup. I noticed the trans temp would go up, then the engine temp, and I actually had to shut down and wait for it to cool a couple times. I thought it was airflow problems due to driving too slow, but it was probably that trans fluid heating up the radiator water. I'll bet this will solve that problem. (Don't worry, I'm over cautious with my temps when in the middle of nowhere...I didn't let the trans get over 200 in the pan, and the coolant was about 220).
My time would be better spent finishing up that topper, in light of the rainy season being here, instead of looking for issues with something that works! I'm declaring this problem solved. As usual, the problem was more with the driver than the truck.....
I think I understand why I kept having temperature issues on my last few trips. I was in 2nd and 3rd most of the time, and wasn't using the lockup. I noticed the trans temp would go up, then the engine temp, and I actually had to shut down and wait for it to cool a couple times. I thought it was airflow problems due to driving too slow, but it was probably that trans fluid heating up the radiator water. I'll bet this will solve that problem. (Don't worry, I'm over cautious with my temps when in the middle of nowhere...I didn't let the trans get over 200 in the pan, and the coolant was about 220).
My time would be better spent finishing up that topper, in light of the rainy season being here, instead of looking for issues with something that works! I'm declaring this problem solved. As usual, the problem was more with the driver than the truck.....
