Thanks for this, I have a 78 with 351M & same trans, believe I would of used a can of gunk to clean that side off first, but then I see there might not be much an issue with getting trash in the hole
Don’t know squat about this stuff and just bought a 73 ford f100 with a transplant 302/C6 vintage 1980. Working the bugs out now. Doesn’t have a vacuum line to the modulator that I know of. I’m gonna have to check that out more.
1980 was a new model year but I would think they would still utilize the modulator. It should mound directly to the transmission and have a rubber line going somewhere to the engine bay. Unless they did something dramatically different for 1980. Good luck!
Next time you do this job, clean the area around the modulator first with some of that engine cleaner and then spray it off carefully at a car wash . Obviously you are leaking oil from somewhere, and doing this might help you see where it is leaking from....not to mention you won't get all hogged up when doing this job....Just saying, as when this happens the color stripe may be gone from the outside of the modulator....in that case call a transmission shop and ask what color they recommend for your make and model to get the right one you need.
Excellent information that I really needed. I have a 1975 F100 and I'm having a high rpm shift from 2nd to 3rd. still trying to determine what is the normal range for it to be in. Thank You!
I installed the black stripe version last year and the shifts are much more firm, so keep that in mind if you’d prefer that. The green stripe was a very average shift. Glad the video was helpful.
@@markhubanks3715 definitely not that fast. Last night when I was leaving my brothers house, I slowly drove down his driveway and it shifted into 3rd at 20 mph. Next time I take it for a spin, I’ll see when it shift when I accelerate fairly fast.
Concerning the carb issue only and not the shift point issue, try the Holley 500 cfm two barrel carb and the difference in throttle response is like night and day. I put one on my 1969 Ford F-250 with a 390 FE engine and it's way better than the old ford carb and I still have the two barrel intake manifold which limits the rev RPM . I'm having the same problem with my shift points after replacing the modulator and they were happening way to fast from 1st to second so I was hoping to find a video how to adjust the screw and if I understand from what you said correctly, I need to turn the screw clockwise to delay the shift point from first to second gear. My friend Chris texted me who is a really good mechanic said try turning the screw counter clockwise and see what happens. 😊
Yes sir, luckily it’s fairly easy to get to the modulator, so making adjustments isn’t too difficult. I have since went to a black-stripe modulator and it shifts MUCH firmer that this green one. I would love to pick up a smaller CFM carburetor at some point, since this truck isn’t a race truck by any means. Everyone was in my ear about getting a huge carburetor, so that’s the direction I went. Luckily I’ve been able to re-jet it and it runs incredibly now. But I think I most certainly lost some low-end torque with the 770.
Just bought a 78 F150 351M with the c6, I am considering adding a larger Trans Cooler with stainless flex lines, do you know the SIZE & TYPE threads used on the trans cooling line connections?? @@TheKeymaster316
When you measure the pin you might want to use a dial caliper or a 1" to 2" micrometer, or the correct size range micrometer, rather than a tape measure. I think some vehicles may have different length pins , so it might be prudent to measure the pin in your specific transmission when you replace your vacuume advance modulator and keep it 's measurement in thousandths in a book in case you lose your pin . If you find your hose has swolen from leaking oil, replace the vacuume line, and if you take off the line and oil comes out of where you adjust it with the tiny screw, replace the modulator. If you are driving it and all at once you have thick white smoke coming out of your exhaust, your modulator blew irs diaphram, and you need to immediately shut off the car and park it , call someone to pick you up,and go get a new modulator same as is in it, as it is sucking your transmission fluid through your carb or EFI ( throttle body). Then refill your lost Transmission fluid, after you replace your modulator, so you don't damage your transmission . That's why you want to immediately pull over to a safe spot when you see the pure thick white smoke right away. Don't keep driving. Sooner the better....the least damage to your transmission from losing fluid through your exhaust. Don't breathe the thick white smoke.....hold your breath.
Mine sputters in reverse and won't really move in reverse unless it's wot then stays stuck at wot could this little vacuum module be my issue for the loss of power in reverse and the sticky throttle
I’m pretty sure it’s connected to the manifold. The hose runs to the backside of the motor and I believe connects to a hard line. Been a minute since I fooled with it.
It’s possible. This one that I installed in the video just went bad a few weeks ago, which surprised me given that it wasn’t that old. At a stoplight, I noticed that when I went to take off, I was moving very slowly. I thought it was a coincidence but it kept happening. I swapped the modulator and it fixed it. So I’m not sure if you would lose 3rd gear but if it doesn’t want to shift, it’s worth replacing this to see if it fixed it.
Would you suggest for someone to get one of these to keep on board ? How often do they fail ? & do they ever fail to just not shift at all?@@TheKeymaster316
I am not sure what trans I have. 1983 E150 302 5 liter engine. It just has P R N D 2 1. So a day ago it got stuck in low gear. Put it in drive and it will get up to maybe 30 mph and won't shift. I ordered a throttle position sensor online but now I don't think that could be it. My manual says there is a kickdown rod that goes to the carburetor somewhere, the throttle detent stop. I see there is also the governor and the Modulator. My manual Haynes is almost worthless. Thanks for the great video. Did you say where the hose on the modulator goes to? I am not a mechanic but I love this van for some reason.
I’m pretty sure the modulator on mine has a hose connected to it. That hose eventually connects to a hard line which goes up into the engine bay and connects to somewhere for a vacuum.
Hey, excuse me, I have a question, where is the reverse sensor or bulb since I just bought a 1977 Ford F150 and they adapted an automatic gearbox and when I put it back, the taillights don't come on?
On manual transmissions, there is a button under the hood that, when you put it in reverse, the linkage under the hood pushes the button in and the light comes on. In an automatic, I’m not 100% sure, but I believe it’s inside the column.
@@WilliamMunny-d8s it was a modulator failure. I’m not sure how much different the one I bought is because I think the original one was in the truck. I have since put a black stripe unit in, which definitely gives you a much firmer shift. But the original one definitely went bad.
@@TheKeymaster316 what were your symptoms that made you think it was definitely bad? my truck shifts hard/crisply but then theres a clunk after the down/upshift. i checked the ujoints but they seem tight. when i was inspecting brakes today i rotated a rear axle with tire off and in park and that sounded like the clunk i keep getting on shifts. does that mean my pinion is too loose on the ring gear? if so how does a guy check this from the outside?
@@WilliamMunny-d8s when I was at a stop light one day, I pushed on the gas peddle like I normally do, but it was only revving. I was barely moving. Then after a few seconds, it finally started to take off. I thought at first that maybe I had a leaky transmission line, but after checking it, it was fine. Did a little digging and found out it could be the modulator. Replaced it and it was back to normal. 👌🏻
Yes sir, that’s correct. And these modulators assist in the shifting process. The one in this video actually went bad a few months ago. It was slipping some kind of bad in first gear. Lots of gas but very slow acceleration. Replaced it and it’s back to normal. 👍🏻
The vacuum modulator is located right on the front of the transmission. If you climb under the truck, you'll see the the vacuum hose going to the modulator. If you pull the hose off, you can adjust it with a small flat-head screwdriver.
So, were you actually driving or did you have your truck up on stands? You got to 55 real fast. I cant get my 1983 Ford Bronco up to that speed for a good minute. What could be the cause of this? Band adjustment?
Yes sir, that was me driving her out on the road. I have a pretty healthy 460 and a Holley 770. Not sure without seeing yours running what it could be but you have to factor in the fuel delivery, timing, and of course your power plant. You should be able to tell if your transmission is slipping if your rpm’s are going up but your speed isn’t.
When I hanged mine the pin wouldn't come out, I'm having issues with my 86 also not shifting to second gear any idea what it could be I also changed the trans filter and still nothing
Anthony Marquez not sure why it’s not shifting for ya, but when they start pulling fluid instead of vacuum, that’s when you have to replace em. And you definitely need to transfer the pin to the new modulator. Good luck!
Yo también tengo ese problema ya le metí todo nuevo ala transmisión pero no hace el segundo cambio que podrá ser también cambie el módulo cómo el q viene en el vídeo y sigue igual alguien que tenga una respuesta a este problema por favor se los agradecería
It's cheap enough to give a try, but it sounds like that could be a much more serious issue with the transmission. It's certainly worth a try checking it out though.
The black stripe is a small diaphragm/low vacuum modulator and is mainly used in heavier vehicles and trucks. It has a low shift point. This modulator is also popular in performance applications due to the low shift point. The purple stripe has a slightly larger diaphragm and is designed for use in normal to heavier passenger vehicles. It has a medium shift point. The green stripe is similar to the purple stripe, but will provide a slightly later shift point. It is designed for normal passenger vehicle usage and is the most popular modulator used the C6. Please make sure facts are correct
@@MrJeremys2388 Great info sir. Thanks for sharing! What would you suggest for a C-6 reverse manual valve body ex-race car? Is it even needed? I do have a vacuum line to from trans to manifold port vacuum source. Have not driven on the street yet, doing lots of conversions and work on her.
My 81 won't shift into overdrive. I can push it to 55 and beyond I'm sure but it sounds like its red lining and I don't feel it shift after 3rd. I've already replaced the modulator and the spark plugs and distributor cap and rotor, as well as the fuel filter. I can't actually tell if its red lining cause I have no rpm gauge, but as I said it doesn't shift after 3rd and sounds like its running harder than it should be. Any help would be greatly appreciated! Thanks for the video!
Unfortunately I don’t have overdrive, so that may be an internal issue inside the transmission. I just have the C6. Trust me, if I get on the highway at 70mph, I’m at around 2700 rpm. Definitely glad I don’t daily drive this truck. Good luck to ya, hopefully it’s a simple solution
@@TheKeymaster316 appreciate the quick response! Thing is I'm not 100% sure what tranny I have in there and I know it had an Inline 6 in it but the old man that sold it to me swapped it for what I think is a 351 M but also not sure on that. I'm still a novice when it comes to vehicles especially classics like this, I could very well have a C6 in there, the C6 isnt a 3 speed Automatic Overdrive transmission?
@@jarrodallen3199 yes sir, the C6 is just 3 gears. I had an 86 F150 about 25 years ago but can’t remember if that truck had overdrive. If you have the C6, that’s probably the reason your screaming along at 55. You gotta remember, back in 81, most interstates across the country were 55, so not that bad. When the speed limit hit 70 like it is now, without an overdrive, you are really spinning those rpm’s. They make aftermarket OD addons but they are very expensive.
Holly self regulated electric fuel pump, good. Holly over complicated, leaks EVERYWHERE, needs constant adjustments carburetor, BAD. If you don't have a cam with the complementing headers, just buy an Edelbrock. Unless you bust a tweak in your spare time the Holly will simply drive you nuts. Carter/edelbrock's once adjusted are trouble free for any motor that's not really souped up. (Edit) Saw the Holly box, grrrr areggg. Sorry for the rant...
Are you talking about cleaning it off before working on it? 🤔. Certainly couldn’t have hurt. Truck sat for about 7 years and I’m sure a lot of the seals and gaskets and such could use replacing.
Thanks for this, I have a 78 with 351M & same trans, believe I would of used a can of gunk to clean that side off first, but then I see there might not be much an issue with getting trash in the hole
Don’t know squat about this stuff and just bought a 73 ford f100 with a transplant 302/C6 vintage 1980. Working the bugs out now. Doesn’t have a vacuum line to the modulator that I know of. I’m gonna have to check that out more.
1980 was a new model year but I would think they would still utilize the modulator. It should mound directly to the transmission and have a rubber line going somewhere to the engine bay. Unless they did something dramatically different for 1980. Good luck!
Next time you do this job, clean the area around the modulator first with some of that engine cleaner and then spray it off carefully at a car wash . Obviously you are leaking oil from somewhere, and doing this might help you see where it is leaking from....not to mention you won't get all hogged up when doing this job....Just saying, as when this happens the color stripe may be gone from the outside of the modulator....in that case call a transmission shop and ask what color they recommend for your make and model to get the right one you need.
Excellent information that I really needed. I have a 1975 F100 and I'm having a high rpm shift from 2nd to 3rd. still trying to determine what is the normal range for it to be in. Thank You!
I installed the black stripe version last year and the shifts are much more firm, so keep that in mind if you’d prefer that. The green stripe was a very average shift. Glad the video was helpful.
Thanks, Do you remember you rpm 2nd to 3rd ? I'm at 53 mph.and 3000 rpm and still in 2nd.
@@markhubanks3715 definitely not that fast. Last night when I was leaving my brothers house, I slowly drove down his driveway and it shifted into 3rd at 20 mph. Next time I take it for a spin, I’ll see when it shift when I accelerate fairly fast.
I just found a video of me getting on it pretty hard and it looked to shift into 3rd at right around 40mph. 👍🏻
So the different stripe Mod is all you need for the change in the shift?? Just swap them out? @@TheKeymaster316
Concerning the carb issue only and not the shift point issue, try the Holley 500 cfm two barrel carb and the difference in throttle response is like night and day. I put one on my 1969 Ford F-250 with a 390 FE engine and it's way better than the old ford carb and I still have the two barrel intake manifold which limits the rev RPM . I'm having the same problem with my shift points after replacing the modulator and they were happening way to fast from 1st to second so I was hoping to find a video how to adjust the screw and if I understand from what you said correctly, I need to turn the screw clockwise to delay the shift point from first to second gear. My friend Chris texted me who is a really good mechanic said try turning the screw counter clockwise and see what happens. 😊
Yes sir, luckily it’s fairly easy to get to the modulator, so making adjustments isn’t too difficult. I have since went to a black-stripe modulator and it shifts MUCH firmer that this green one. I would love to pick up a smaller CFM carburetor at some point, since this truck isn’t a race truck by any means. Everyone was in my ear about getting a huge carburetor, so that’s the direction I went. Luckily I’ve been able to re-jet it and it runs incredibly now. But I think I most certainly lost some low-end torque with the 770.
Just bought a 78 F150 351M with the c6, I am considering adding a larger Trans Cooler with stainless flex lines, do you know the SIZE & TYPE threads used on the trans cooling line connections??
@@TheKeymaster316
@@REVNUMANEWBERN I sure don’t. Hopefully the new one will have those specifications in the documentation.
When you measure the pin you might want to use a dial caliper or a 1" to 2" micrometer, or the correct size range micrometer, rather than a tape measure. I think some vehicles may have different length pins , so it might be prudent to measure the pin in your specific transmission when you replace your vacuume advance modulator and keep it 's measurement in thousandths in a book in case you lose your pin . If you find your hose has swolen from leaking oil, replace the vacuume line, and if you take off the line and oil comes out of where you adjust it with the tiny screw, replace the modulator. If you are driving it and all at once you have thick white smoke coming out of your exhaust, your modulator blew irs diaphram, and you need to immediately shut off the car and park it , call someone to pick you up,and go get a new modulator same as is in it, as it is sucking your transmission fluid through your carb or EFI ( throttle body). Then refill your lost Transmission fluid, after you replace your modulator, so you don't damage your transmission . That's why you want to immediately pull over to a safe spot when you see the pure thick white smoke right away. Don't keep driving. Sooner the better....the least damage to your transmission from losing fluid through your exhaust. Don't breathe the thick white smoke.....hold your breath.
Mine sputters in reverse and won't really move in reverse unless it's wot then stays stuck at wot could this little vacuum module be my issue for the loss of power in reverse and the sticky throttle
I don't think this is your issue as this only adjusts the shift points if im not mistaken i.e 1st 2nd and 3rd
Is your vacuum line connected to the carburetor or the intake manifold?
I’m pretty sure it’s connected to the manifold. The hose runs to the backside of the motor and I believe connects to a hard line. Been a minute since I fooled with it.
What happens when the modulator fails? Would it stop you from getting into 3rd?
It’s possible. This one that I installed in the video just went bad a few weeks ago, which surprised me given that it wasn’t that old. At a stoplight, I noticed that when I went to take off, I was moving very slowly. I thought it was a coincidence but it kept happening. I swapped the modulator and it fixed it. So I’m not sure if you would lose 3rd gear but if it doesn’t want to shift, it’s worth replacing this to see if it fixed it.
Would you suggest for someone to get one of these to keep on board ? How often do they fail ? & do they ever fail to just not shift at all?@@TheKeymaster316
I am not sure what trans I have. 1983 E150 302 5 liter engine. It just has P R N D 2 1. So a day ago it got stuck in low gear. Put it in drive and it will get up to maybe 30 mph and won't shift. I ordered a throttle position sensor online but now I don't think that could be it. My manual says there is a kickdown rod that goes to the carburetor somewhere, the throttle detent stop. I see there is also the governor and the Modulator. My manual Haynes is almost worthless.
Thanks for the great video. Did you say where the hose on the modulator goes to? I am not a mechanic but I love this van for some reason.
I’m pretty sure the modulator on mine has a hose connected to it. That hose eventually connects to a hard line which goes up into the engine bay and connects to somewhere for a vacuum.
Hey, excuse me, I have a question, where is the reverse sensor or bulb since I just bought a 1977 Ford F150 and they adapted an automatic gearbox and when I put it back, the taillights don't come on?
On manual transmissions, there is a button under the hood that, when you put it in reverse, the linkage under the hood pushes the button in and the light comes on. In an automatic, I’m not 100% sure, but I believe it’s inside the column.
@@TheKeymaster316 thank you so much👍🏻👏🏻
great! sharing the pin length was extremely helpful!!!!
SO was this modulator failing in some way or he just wanted a higher rpm band shift points for towing or performance or something like that?
@@WilliamMunny-d8s it was a modulator failure. I’m not sure how much different the one I bought is because I think the original one was in the truck. I have since put a black stripe unit in, which definitely gives you a much firmer shift. But the original one definitely went bad.
@@TheKeymaster316 what were your symptoms that made you think it was definitely bad?
my truck shifts hard/crisply but then theres a clunk after the down/upshift.
i checked the ujoints but they seem tight.
when i was inspecting brakes today i rotated a rear axle with tire off and in park and that sounded like the clunk i keep getting on shifts.
does that mean my pinion is too loose on the ring gear? if so how does a guy check this from the outside?
@@WilliamMunny-d8s when I was at a stop light one day, I pushed on the gas peddle like I normally do, but it was only revving. I was barely moving. Then after a few seconds, it finally started to take off. I thought at first that maybe I had a leaky transmission line, but after checking it, it was fine. Did a little digging and found out it could be the modulator. Replaced it and it was back to normal. 👌🏻
your vehicle could use a good pressure washing underneath I did that to a few Vehicles totally worth it
I’ve given it some TLC since this video was made. 😁
So the kickdown rod must be what kicks your transmission to a lower gear when you step on the gas pedal to the metal or floor it.
Yes sir, that’s correct. And these modulators assist in the shifting process. The one in this video actually went bad a few months ago. It was slipping some kind of bad in first gear. Lots of gas but very slow acceleration. Replaced it and it’s back to normal. 👍🏻
@@TheKeymaster316 Thanks
Where is the valve located?
The vacuum modulator is located right on the front of the transmission. If you climb under the truck, you'll see the the vacuum hose going to the modulator. If you pull the hose off, you can adjust it with a small flat-head screwdriver.
@@TheKeymaster316 I came to the conclusion that I have a later model trans.It is all electric no vacuum.Thank You.
So, were you actually driving or did you have your truck up on stands? You got to 55 real fast. I cant get my 1983 Ford Bronco up to that speed for a good minute. What could be the cause of this? Band adjustment?
Yes sir, that was me driving her out on the road. I have a pretty healthy 460 and a Holley 770. Not sure without seeing yours running what it could be but you have to factor in the fuel delivery, timing, and of course your power plant. You should be able to tell if your transmission is slipping if your rpm’s are going up but your speed isn’t.
@@TheKeymaster316 thanks for the info
Hello, and how long is the small bar of a vacuum for ford c4 gear box? Thank you
Sorry, Alejandro, I’m not familiar with the C4.
When I hanged mine the pin wouldn't come out, I'm having issues with my 86 also not shifting to second gear any idea what it could be I also changed the trans filter and still nothing
Anthony Marquez not sure why it’s not shifting for ya, but when they start pulling fluid instead of vacuum, that’s when you have to replace em. And you definitely need to transfer the pin to the new modulator. Good luck!
Figure out you problem?
Yo también tengo ese problema ya le metí todo nuevo ala transmisión pero no hace el segundo cambio que podrá ser también cambie el módulo cómo el q viene en el vídeo y sigue igual alguien que tenga una respuesta a este problema por favor se los agradecería
My 1989 Ford f150 will not shift into 3rd or overdrive. The fluid looks really good. Could it be the modulator causing my problem?
It's cheap enough to give a try, but it sounds like that could be a much more serious issue with the transmission. It's certainly worth a try checking it out though.
@@TheKeymaster316 ty for your time. I do appreciate it.
Did you figure it out. I have the same issue
@@cornbreadandbiscuits1854 No, it hasn't hit high enough priority yet, sorry.
FYI, the black is a high pressure calve while the green is OEM pressure.
jperiodchapin yeah, may have to try the black modulator one of these days.
Black is low vaccume. For a truck
The black stripe is a small diaphragm/low vacuum modulator and is mainly used in heavier vehicles and trucks. It has a low shift point. This modulator is also popular in performance applications due to the low shift point.
The purple stripe has a slightly larger diaphragm and is designed for use in normal to heavier passenger vehicles. It has a medium shift point.
The green stripe is similar to the purple stripe, but will provide a slightly later shift point. It is designed for normal passenger vehicle usage and is the most popular modulator used the C6. Please make sure facts are correct
@@MrJeremys2388 Great info sir. Thanks for sharing! What would you suggest for a C-6 reverse manual valve body ex-race car? Is it even needed? I do have a vacuum line to from trans to manifold port vacuum source. Have not driven on the street yet, doing lots of conversions and work on her.
@@MrJeremys2388 ok, how about the white stripe?
What way did you turn it?
I believe it’s clockwise for a firmer shift.
Thank you I think I'm miss that pin.
thanks to this video i find out that my truck its missing this pin
No problem, glad I could help!
What size wrench do you need
1/2”. 👌🏻
My 81 won't shift into overdrive. I can push it to 55 and beyond I'm sure but it sounds like its red lining and I don't feel it shift after 3rd. I've already replaced the modulator and the spark plugs and distributor cap and rotor, as well as the fuel filter. I can't actually tell if its red lining cause I have no rpm gauge, but as I said it doesn't shift after 3rd and sounds like its running harder than it should be. Any help would be greatly appreciated! Thanks for the video!
Unfortunately I don’t have overdrive, so that may be an internal issue inside the transmission. I just have the C6. Trust me, if I get on the highway at 70mph, I’m at around 2700 rpm. Definitely glad I don’t daily drive this truck. Good luck to ya, hopefully it’s a simple solution
@@TheKeymaster316 appreciate the quick response! Thing is I'm not 100% sure what tranny I have in there and I know it had an Inline 6 in it but the old man that sold it to me swapped it for what I think is a 351 M but also not sure on that. I'm still a novice when it comes to vehicles especially classics like this, I could very well have a C6 in there, the C6 isnt a 3 speed Automatic Overdrive transmission?
@@jarrodallen3199 yes sir, the C6 is just 3 gears. I had an 86 F150 about 25 years ago but can’t remember if that truck had overdrive. If you have the C6, that’s probably the reason your screaming along at 55. You gotta remember, back in 81, most interstates across the country were 55, so not that bad. When the speed limit hit 70 like it is now, without an overdrive, you are really spinning those rpm’s. They make aftermarket OD addons but they are very expensive.
@@TheKeymaster316 10-4 makes sense. I guess it's the same answer as always then, keep doing some research. I really appreciate the responses!
@@jarrodallen3199 anytime, good luck to ya. 👍🏻
Holly self regulated electric fuel pump, good.
Holly over complicated, leaks EVERYWHERE, needs constant adjustments carburetor, BAD.
If you don't have a cam with the complementing headers, just buy an Edelbrock.
Unless you bust a tweak in your spare time the Holly will simply drive you nuts. Carter/edelbrock's once adjusted are trouble free for any motor that's not really souped up.
(Edit)
Saw the Holly box, grrrr areggg.
Sorry for the rant...
Once I tuned this Holley on this truck, it has been trouble-free and runs fantastic. ;)
@TheKeymaster316
No shade man, hope you have more luck than myself and others I've seen.
or spray cleaner.
Clean it first maybe?😂
En español
the car wash would have made a better video and cleaner job for only a few quarters.
Are you talking about cleaning it off before working on it? 🤔. Certainly couldn’t have hurt. Truck sat for about 7 years and I’m sure a lot of the seals and gaskets and such could use replacing.
Needs to speak up can't hear it
Duly noted. 👌🏻
This is a very good video. Very informative, thank you very much. Looking forward to more of your videos!