700r4 questions

[Dutch Rutter]

Hello everyone!

I recently had a shop (same shop that replaced the 700r4 a year or two ago) do some brake work on my 83 k20.
I got the truck back from them, and I found out they changed my transmission cooler lines around without my knowledge, so I put them back.

I had them bypassing the in radiator "cooler" and going directly to my large stacked plate cooler. This is how I put them back.
I also found out that they overfilled my transmission about a quart too full.
This was causing some massive heat build up and foaming fluid.

Today, I drained the pan and got new fluid to mid of the hash marks on the check stick (warm).
I drove it nicely for about 30 minutes. I noticed the temp gauge hanging a bit high (175-200) and its quite cold outside. Normally, it would stay around 137 in these kind of temps. It would only be getting to 175 in 90 degree+ weather while pulling a trailer on a slow, steep gravel road.
I am also pretty certain my torque converter is no longer locking up. I tested this by cruising along (55-65 mph) and taping the brakes while watching the tach. I did not see the 300-400rpm jump from the converter unlocking. (before, I could see that jump with the same test).

So now... I am trying to go through and check the function of the converter lockup before I end up having to call the shop up and see what they suggest.

The current setup is all pretty stock.
I have the brake switch, the vacuum switch (connected to the manifold vacuum port on the driver's side of my edelbrock 1406), and the factory harness running down to the transmission.

First question - is the manifold vacuum port the correct port for that vacuum lock-up switch? and if so what would be the next thing to check?

or should I just suck it up and call the shop and let them deal with it?

Thanks..

 

[AuroraGirl]

Hello everyone!

I recently had a shop (same shop that replaced the 700r4 a year or two ago) do some brake work on my 83 k20.
I got the truck back from them, and I found out they changed my transmission cooler lines around without my knowledge, so I put them back.

I had them bypassing the in radiator "cooler" and going directly to my large stacked plate cooler. This is how I put them back.
I also found out that they overfilled my transmission about a quart too full.
This was causing some massive heat build up and foaming fluid.

Today, I drained the pan and got new fluid to mid of the hash marks on the check stick (warm).
I drove it nicely for about 30 minutes. I noticed the temp gauge hanging a bit high (175-200) and its quite cold outside. Normally, it would stay around 137 in these kind of temps. It would only be getting to 175 in 90 degree+ weather while pulling a trailer on a slow, steep gravel road.
I am also pretty certain my torque converter is no longer locking up. I tested this by cruising along (55-65 mph) and taping the brakes while watching the tach. I did not see the 300-400rpm jump from the converter unlocking. (before, I could see that jump with the same test).

So now... I am trying to go through and check the function of the converter lockup before I end up having to call the shop up and see what they suggest.

The current setup is all pretty stock.
I have the brake switch, the vacuum switch (connected to the manifold vacuum port on the driver's side of my edelbrock 1406), and the factory harness running down to the transmission.

First question - is the manifold vacuum port the correct port for that vacuum lock-up switch? and if so what would be the next thing to check?

or should I just suck it up and call the shop and let them deal with it?

Thanks..

Um... do you specifically want your trans to run cold, by chance.. or do you have a reason to bypass the radiator? You should run your trans, normally, to the cooler, then to the radiator, then back to the trans. it helps warm up when cold but it still will do a lot to cool down. Also, how did you check your trans fluid? Like, under what conditions and what did you do to determine it was too full

 

[Grumpy]

I agree with Aurora. Your primary vacuum source for the lockup switch should be from the intake manifold just behind the carburetor; then check the lines to the thermac located on the water neck. On this vintage, verify the vacuum lines have not turned to spaghetti and cracked. Everything gets old sooner or later.

 

[Dutch Rutter]

@AuroraGirl and @Grumpy

Thanks for the responses to this. It has really had me stressed out like crazy these last few months. And I mean "I should sell this thing or take my engine out and scrap the rest" level of stressed out.

When I got the truck back from the shop, I checked the trans level like you normally would and found fluid to be about 1-1.5 inches above the full mark on the stick. The foaming fluid (from what I've read online) is another sign of overfull fluid. I drained about 7 quarts out of it. It was darker then new fluid but not burnt smelling or black. (temps did show 250+ about 4 times before I found this) I added 5qts of new fluid back in, ran it through the gears, checked and it was lower of the hash marks, took it for a drive to get it warm, checked at normal operating temp, and it is now right in the middle of the hash marks.

Side note: I do have one of these cooling pans on the trans, so it takes just a touch more fluid then a stock pan

Derale Cooling Products 14204 Derale Transmission Pans | Summit Racing

Free Shipping - Derale Transmission Pans with qualifying orders of $109. Shop Automatic Transmission Pans at Summit Racing.

www.summitracing.com

I do want the trans to be running pretty cold. I have a pretty accurate temp gauge hooked up and I've been monitoring it pretty closely ever since installing that along with the now second transmission.
When ran to the cooler directly and bypassing the in rad cooler it will heat up to around 137 with normal driving (in winter) in about 10 minutes of driving. and it will stay around there. My coolant temp runs about the same heat wise.
However, when I run it through he rad, the trans temp shows 37 degrees higher then I feel is normal. (I can be wrong I am not above admitting that) 10 minutes of normal driving (in winter months), it shows 175, mid gauge. In summer it gets hot (210) in normal traffic unloaded. and I have had to stop a few times when pulling a small trailer up slow gravel roads because it was showing 250 (full gauge), even with the aux electric fan on. When running with the rad bypassed it only gets up to 190 at its highest. It doesn't get THAT cold around here even during the winter, 20 degrees is about as low as I've ever seen.

The gauge is pretty accurate within 5-8 degrees. I verified with a thermal imaging camera (perks of working at a fire station).

My temps now are ok but not where they normally would be. I do see some spikes (210) when driving around 40mph but when I drive it at 55-60 they come down to around 175. With the radiator bypassed that very large cooler I have should have that temp down to 140. The cooler I have is a very large stacked plate cooler, which also has a thermal bypass built into it. So when the fluid temps are lower (under 150) it will only use 1/3rd of the cooler before sending the fluid back to the trans. but when the temps get over 150 it opens up the full cooler before sending the fluid back. It actually works quite well. I believe my temps are higher then normal because the transmission is now not locking up the TC at all. I checked with the brake pedal test and was not seeing the TC unlock on the tach. Normally, doing that would show a jump of 300-400 rpm. Now I get no change at all. From my understanding, a stock 700r4 when locked provides the most fluid pressure to the lines, which provides the most cooling to the transmission. Mine should be locking in 3rd and 4th gears (that is how it worked before). But now I am pretty confident it is not locking at all.

So with my edelbrock carb and manifold (how its been setup and worked) that driver side port is the manifold vacuum port and not the timed (ported) vacuum port. So I should be alright there.
I am going to go through today and verify power from the brake switch, then follow the order of components and verify power from the vacuum switch, then lastly verify power at the plug on the trans itself. If I have power there.... I should verify I can hear the lockup solenoid click (if it does, then my trans is working and IS trying to lock but cannot for some reason), if it does not click then the solenoid will be getting replaced which might correct the problem.

 

[Dutch Rutter]

Started checking for power and found the vacuum switch on the firewall has no hot to it when the key is on. I then went upstream to the brake pedal switch (pictured) and found the same. Does anyone know where those get their power?

You must be registered for see images attach

I am guessing its fused somewhere..

 

[AuroraGirl]

@AuroraGirl and @Grumpy

Thanks for the responses to this. It has really had me stressed out like crazy these last few months. And I mean "I should sell this thing or take my engine out and scrap the rest" level of stressed out.

When I got the truck back from the shop, I checked the trans level like you normally would and found fluid to be about 1-1.5 inches above the full mark on the stick. The foaming fluid (from what I've read online) is another sign of overfull fluid. I drained about 7 quarts out of it. It was darker then new fluid but not burnt smelling or black. (temps did show 250+ about 4 times before I found this) I added 5qts of new fluid back in, ran it through the gears, checked and it was lower of the hash marks, took it for a drive to get it warm, checked at normal operating temp, and it is now right in the middle of the hash marks.

Side note: I do have one of these cooling pans on the trans, so it takes just a touch more fluid then a stock pan

Derale Cooling Products 14204 Derale Transmission Pans | Summit Racing

Free Shipping - Derale Transmission Pans with qualifying orders of $109. Shop Automatic Transmission Pans at Summit Racing.

www.summitracing.com

I do want the trans to be running pretty cold. I have a pretty accurate temp gauge hooked up and I've been monitoring it pretty closely ever since installing that along with the now second transmission.
When ran to the cooler directly and bypassing the in rad cooler it will heat up to around 137 with normal driving (in winter) in about 10 minutes of driving. and it will stay around there. My coolant temp runs about the same heat wise.
However, when I run it through he rad, the trans temp shows 37 degrees higher then I feel is normal. (I can be wrong I am not above admitting that) 10 minutes of normal driving (in winter months), it shows 175, mid gauge. In summer it gets hot (210) in normal traffic unloaded. and I have had to stop a few times when pulling a small trailer up slow gravel roads because it was showing 250 (full gauge), even with the aux electric fan on. When running with the rad bypassed it only gets up to 190 at its highest. It doesn't get THAT cold around here even during the winter, 20 degrees is about as low as I've ever seen.

The gauge is pretty accurate within 5-8 degrees. I verified with a thermal imaging camera (perks of working at a fire station).

My temps now are ok but not where they normally would be. I do see some spikes (210) when driving around 40mph but when I drive it at 55-60 they come down to around 175. With the radiator bypassed that very large cooler I have should have that temp down to 140. The cooler I have is a very large stacked plate cooler, which also has a thermal bypass built into it. So when the fluid temps are lower (under 150) it will only use 1/3rd of the cooler before sending the fluid back to the trans. but when the temps get over 150 it opens up the full cooler before sending the fluid back. It actually works quite well. I believe my temps are higher then normal because the transmission is now not locking up the TC at all. I checked with the brake pedal test and was not seeing the TC unlock on the tach. Normally, doing that would show a jump of 300-400 rpm. Now I get no change at all. From my understanding, a stock 700r4 when locked provides the most fluid pressure to the lines, which provides the most cooling to the transmission. Mine should be locking in 3rd and 4th gears (that is how it worked before). But now I am pretty confident it is not locking at all.

So with my edelbrock carb and manifold (how its been setup and worked) that driver side port is the manifold vacuum port and not the timed (ported) vacuum port. So I should be alright there.
I am going to go through today and verify power from the brake switch, then follow the order of components and verify power from the vacuum switch, then lastly verify power at the plug on the trans itself. If I have power there.... I should verify I can hear the lockup solenoid click (if it does, then my trans is working and IS trying to lock but cannot for some reason), if it does not click then the solenoid will be getting replaced which might correct the problem.

Is there a reason you want to avoid the radiator?
what diameter line do you use between the trans and the cooler

A radiator cooler will be inherently more efficient at cooling than a air cooler IN That the fluid to fluid exchange is better than fluid to air. mind you, being your cooler is large and has airflow(you have electric fans if I recall right, right? or perhaps just an auxillary fan..? for some reason I feel you have a lot of fans.

Anyway, with your bypass, I am not too worried. but your fluid situation could have been too high from both temp and being aerated. as in, it may not have been too low. but I do want to ask, do you know what fluid they used in your trans? wasnt no type F was it?
Is your TV cable adjusted right?
beyond that, you found your problem partially with the switches. fix that of course. but im wondering now too about your filter....

Your pan is larger. is your filter have a longer pickup tube or is it just dangling in the seal with nothing to hold it up and sealed.

 

[Dutch Rutter]

Is there a reason you want to avoid the radiator?
what diameter line do you use between the trans and the cooler

A radiator cooler will be inherently more efficient at cooling than a air cooler IN That the fluid to fluid exchange is better than fluid to air. mind you, being your cooler is large and has airflow(you have electric fans if I recall right, right? or perhaps just an auxillary fan..? for some reason I feel you have a lot of fans.

Anyway, with your bypass, I am not too worried. but your fluid situation could have been too high from both temp and being aerated. as in, it may not have been too low. but I do want to ask, do you know what fluid they used in your trans? wasnt no type F was it?
Is your TV cable adjusted right?
beyond that, you found your problem partially with the switches. fix that of course. but im wondering now too about your filter....

Your pan is larger. is your filter have a longer pickup tube or is it just dangling in the seal with nothing to hold it up and sealed.

I don't really have any reason to avoid the radiator cooler other then through my testing/monitoring I found it to add more heat to the trans fluid and not really help with cooling it back down. This might be associated with the radiator that I have. its an aluminum, plastic side cap type. does fine with cooling the coolant. But I really have no idea where it stacks for the built in trans cooler. If I could test it and see good results with it, I wouldn't hesitate to run it.

I have a mechanical clutch fan on the front of the engine and a wired in auxiliary Electric fan in front of the add-on trans cooler.

I would sure hope they would use Dex III as that is what it calls for and what the check stick says (I put in DEX III). That being said.... I never saw any documentation on what fluid they put in, and I will admit I am not too trusting of any local shops lately. The fluid has always been pink/red, and even now when I took it for a drive it did get warmer then usual. I checked the fluid it showed correct but still has some small bubbles/foam to it. (pic attached)

TV cable feels right and doesn't look to have been messed with.

The pan is a bit deeper but doesn't require an extension for the pickup (I had the same thought when I was ordering it) it has "cooling" tubes that run front to rear. Those tubes allow air to pass through them supposedly passively cooling the fluid. The tubes take up the extra depth so the filter rests on top of them.

With the way its been acting, I planned on going through and dropping the pan to replace the filter, another drain and fill and replace the pan gasket. Those parts will arrive this coming week.

I did trace some power down and I'm not too sure where to go with it now..
My truck came with cruise control and the 700r4 from the factory. The cruise has never worked since its been in my possession, and the wiring under the hood is just zip tied out of the way.
I found that the power to the brake switch is only present when the cruise control is set to "ON" on the stalk controls. With it at "OFF" I don't get any power to those wires on the back of the brake switch. I don't know if that is how that is supposed to be or not.
I pulled each fuse one at a time and they checked out fine.
Even with power to the brake switch (cruise in the ON position) and the brake not pressed, with the key ON. I do not have power going to the vacuum switch.

The transmission itself is still under warranty with the shop (installed in late 2020 and has a 3 year unlimited mile warranty). So I'm debating on calling them up and seeing if they want to try and figure this out or not. But I'm not sure if I want to trust them with it again.

 

[AuroraGirl]

I don't really have any reason to avoid the radiator cooler other then through my testing/monitoring I found it to add more heat to the trans fluid and not really help with cooling it back down. This might be associated with the radiator that I have. its an aluminum, plastic side cap type. does fine with cooling the coolant. But I really have no idea where it stacks for the built in trans cooler. If I could test it and see good results with it, I wouldn't hesitate to run it.

I have a mechanical clutch fan on the front of the engine and a wired in auxiliary Electric fan in front of the add-on trans cooler.

I would sure hope they would use Dex III as that is what it calls for and what the check stick says (I put in DEX III). That being said.... I never saw any documentation on what fluid they put in, and I will admit I am not too trusting of any local shops lately. The fluid has always been pink/red, and even now when I took it for a drive it did get warmer then usual. I checked the fluid it showed correct but still has some small bubbles/foam to it. (pic attached)

TV cable feels right and doesn't look to have been messed with.

The pan is a bit deeper but doesn't require an extension for the pickup (I had the same thought when I was ordering it) it has "cooling" tubes that run front to rear. Those tubes allow air to pass through them supposedly passively cooling the fluid. The tubes take up the extra depth so the filter rests on top of them.

With the way its been acting, I planned on going through and dropping the pan to replace the filter, another drain and fill and replace the pan gasket. Those parts will arrive this coming week.

I did trace some power down and I'm not too sure where to go with it now..
My truck came with cruise control and the 700r4 from the factory. The cruise has never worked since its been in my possession, and the wiring under the hood is just zip tied out of the way.
I found that the power to the brake switch is only present when the cruise control is set to "ON" on the stalk controls. With it at "OFF" I don't get any power to those wires on the back of the brake switch. I don't know if that is how that is supposed to be or not.
I pulled each fuse one at a time and they checked out fine.
Even with power to the brake switch (cruise in the ON position) and the brake not pressed, with the key ON. I do not have power going to the vacuum switch.

The transmission itself is still under warranty with the shop (installed in late 2020 and has a 3 year unlimited mile warranty). So I'm debating on calling them up and seeing if they want to try and figure this out or not. But I'm not sure if I want to trust them with it again.

I would definitely question the fluid, I wonder if they put Type F in there. Also remember, a ATF usually is meant to grab air and in doing so, it expels it. do you have a vent issue? its a problem when you cavitate or you introduce air(not sure but check things) that your atf becomes your enemy.

when my cars transaxle had strawberry milkshake come out when i pulled the pan, it surprised me because the coolant was not getting in

It was from cavitation only because of a internal pressure loss that was huge

You must be registered for see images attach

I had a hose fail and the pipes werent tight so the pressure was just shooting straight into the pan. it was also overfilled. that didnt help.

The fluid was fine but type F has properties that worked for what it was made for but not in a 700r4 is what im saying, and apparently trans shops like Type F?
I would almost wonder if they put DEX VI in too, because that would probably be too THIN and lead to various issues. Idc what gm says, Dex vi was made for a eleectronic modern trans. its slippery-er and thinner than dex 3.

a 700r4 needs something better
itORIGINALLY would have had Dex II

You must be registered for see images attach

Dex 2 had a green / almost wear looking to it when it was barely even used. the left one. right is worn.

 

[Dutch Rutter]

Thanks @AuroraGirl !! That is alot of food for thought. I think I'm going to give them a call tomorrow and pick their brain about this. If they want to take a look I might as well give them the chance since they would be the ones taking care of any warranty work.

VERY worst case scenario... I end up putting another transmission into it. I have a good line on either a TREMEC TR-4050 5-Speed or a Silver Sport Transmissions A41X 4-Speed Automatic which is based on the 4l60e.. I have no idea how much either of those swap kits cost yet.. but it can't be more then a $40k+ used pickup.

 

[Grumpy]

You may wish to wire in a tell-tale for your TCC. This may confirm the nature of your complaint regarding the spikes in temperatures. If the spikes are not related to the TCC engagement and you have not noted any flare, I would suspect air ingress or the filter is not sealing correctly at the intake. Small deviations in temperature are normal, as well routing the transmission oil through the radiator for temperature control is strongly advised. All oils and lubricants are designed to function with particular components (in this case, clutches and seals) and within specific temperature ranges, oil that is too cold will have an effect on performance.

 

[Dutch Rutter]

@AuroraGirl and @Grumpy

I went ahead and added the radiator cooler back into the loop last night. Got it back to the shop this morning. And I don't know if the stars are aligned just right or if that in radiator cooler was the ticket but the trans temps stayed pretty low, it hit mid gauge once but came back down rather quickly.

I agree using the in rad cooler should be the way to go.

I informed the shop of this, they said there are a few things they want to check out on it. Considering they installed it 9/2020 with an unlimited mile, 3 year warranty. I would expect them to want to give things a thorough check.

After I talked to the shop yesterday, I believe they are suspecting a low line pressure issue. But I did also tell them that I think the converter isn't locking up for some reason or another. I guess we'll see what they say.

I do admit, I am a little fearful or what these temps will be once summer comes around and I can only imagine what will happen when I try towing (4000lbs or so) with it in summer heat.

Edit: I forgot to mention the vacuum lines are all new.

 

[AuroraGirl]

@AuroraGirl and @Grumpy

I went ahead and added the radiator cooler back into the loop last night. Got it back to the shop this morning. And I don't know if the stars are aligned just right or if that in radiator cooler was the ticket but the trans temps stayed pretty low, it hit mid gauge once but came back down rather quickly.

I agree using the in rad cooler should be the way to go.

I informed the shop of this, they said there are a few things they want to check out on it. Considering they installed it 9/2020 with an unlimited mile, 3 year warranty. I would expect them to want to give things a thorough check.

After I talked to the shop yesterday, I believe they are suspecting a low line pressure issue. But I did also tell them that I think the converter isn't locking up for some reason or another. I guess we'll see what they say.

I do admit, I am a little fearful or what these temps will be once summer comes around and I can only imagine what will happen when I try towing (4000lbs or so) with it in summer heat.

Edit: I forgot to mention the vacuum lines are all new.

The rad cooler should NOT be adding a lot of temp to your fluid when you have a cooler like yours before it. if it heats it up,it means its cold. your transmission temps, if things are working, should be good. youre using a big 4 core copper/brass rad, arent you? Or was it a large aluminum?

can you show your shroud, fan, rad setup?
using good quality clean coolant?

 

[Dutch Rutter]

The rad cooler should NOT be adding a lot of temp to your fluid when you have a cooler like yours before it. if it heats it up,it means its cold. your transmission temps, if things are working, should be good. youre using a big 4 core copper/brass rad, arent you? Or was it a large aluminum?

can you show your shroud, fan, rad setup?
using good quality clean coolant?

The radiator is a large aluminum with plastic side caps type. It's supposed to be an equivalent to a 4 core brass type.

Coolant is good nice, clean and green, nothing too old there.

I apparently don't have any pictures of the setup but I'll get some once I get the truck back.
It's a solid stock shroud, the stock AC condenser is still in place (not hooked up at all), and in front of that I have this stacked plate cooler

Hayden Automotive 699 Hayden Rapid-Cool Transmission Oil Coolers with Thermal Bypass | Summit Racing

Free Shipping - Hayden Rapid-Cool Transmission Oil Coolers with Thermal Bypass with qualifying orders of $109. Shop Fluid Coolers at Summit Racing.

www.summitracing.com

With a 1500 CFM fan powered with a relay which runs off a switch in the cab.

I've tried to set it all up well and reliably which is part of the frustration. I mainly installed the fan to only be used when in traffic, or slow offroad trails.

I also have this HUGE (should be overkill) tru-cool HB7 cooler on the shelf thats been waiting to go in. It might not fit behind the stock grill with the fan so that'll need some figuring if it's going to be used.

H7B | Tru-Cool

Edit: The rubber lines from the metal line and radiator to the cooler are 3/8 inch.

 

[AuroraGirl]

The radiator is a large aluminum with plastic side caps type. It's supposed to be an equivalent to a 4 core brass type.

Coolant is good nice, clean and green, nothing too old there.

I apparently don't have any pictures of the setup but I'll get some once I get the truck back.
It's a solid stock shroud, the stock AC condenser is still in place (not hooked up at all), and in front of that I have this stacked plate cooler

Hayden Automotive 699 Hayden Rapid-Cool Transmission Oil Coolers with Thermal Bypass | Summit Racing

Free Shipping - Hayden Rapid-Cool Transmission Oil Coolers with Thermal Bypass with qualifying orders of $109. Shop Fluid Coolers at Summit Racing.

www.summitracing.com

With a 1500 CFM fan powered with a relay which runs off a switch in the cab.

I've tried to set it all up well and reliably which is part of the frustration. I mainly installed the fan to only be used when in traffic, or slow offroad trails.

I also have this HUGE (should be overkill) tru-cool HB7 cooler on the shelf thats been waiting to go in. It might not fit behind the stock grill with the fan so that'll need some figuring if it's going to be used.

H7B | Tru-Cool

Edit: The rubber lines from the metal line and radiator to the cooler are 3/8 inch.

do you by chance have any sharp bends or anything like that

also, what temps are you afraid of / what have you traditionally seen on your trans

also, You ever going to use your ac condensor? If not, you can make room.

 

[SquareRoot]

So glad I put a nv4500 in my beast. I've hated every slushbox I have owned.