I have a 74 Mav w/a 250. I want to replace the original leaking modulator, I was reading a post from another member awhile back to get a green stripe one with only 1 port instead of 2 or just block the other small port. One, I can't find any with a green stripe-only black at all the stores. Do they make a green one(supposedly better shifts-what I've heard), for this year? It is the push in variety.
Yes they make them for that year and if you adjust it right it will shift better. Do you have a local Oreillys in your area? If so here is the link for the part. If you dont you can always order it online. http://www.oreillyauto.com/site/c/d...=Search_C0073_1132209_2212&pt=C0073&ppt=C0338
Just wondering how do you adjust it??? And how does it make it better with one port instead of twoo?? I work at oreillys so I got no prob buying this if it helps my tranny out haha
Where the vacuum hose plugs into the modulator, you should be able to take a very small flat head and turn it to adjust how quickly it changes gears. I dont rememer which way you turn it I would wait on someone else to clear that up.
In a nutshell,The more you turn it clockwise the longer between shifts.Had a C6 with no kickdown rod ended up turning the screw all the way to the bottom and back out 1/4 turn just to get it the gear changes farther apart.
When you change the modulator do NOT adjust it! The adjustment is there for fine tuning the shift points by measuring the amount of spring pressure and adjusting it to a set value. If you set the shift point too high it will cause a mushy shift that will burn the clutches and wear your C4 out quickly. After you install the new modulator check to see where it shifts at light acceleration, medium acceleration, and hard acceleration. Full throttle shifts are not affected by adjusting the modulator - they are controlled by the governor. The best speeds for the shifts on a C4 (for the transmission) are: LIGHT ACCELERATION; 1-2 shift at 5-7 mph 2-3 shift at 10 - 15mph MEDIUM ACCELERATION; 1-2 shift at 10-12 mph 2-3 shift 20-25 mph HARD ACCELERATION; 1-2 shift at 15-17 mph 2-3 shift at 28-30 mph FULL THROTTLE; 1-2 shift at 35-40 mph 2-3 shift at 60-75 mph. You need to have the kick-down linkage installed and properly adjusted in order for the shifts to work properly. Installing a 40-2 TransGo Reprogramming kit will make the shifts faster and just slightly later. You can install a modulator rod that is longer (maximum length is 1 5/8") to make the shifts later without hurting the transmission. If the modulator has to be adjusted it should only be adjusted a maximum of three turns in either direction - more can damage the diaphragm and cause it to leak ATF into the intake. The two port modulator was made to smooth shifts in cars with EGRs and it caused more problems than it fixed so it was used from late 73 to early 74 and then dropped.
I know this is old but I have a question..I have had shifting problems on my 73 302..i got under my car and noticed that I have a green stripe modulator...i looked around it to find any vaccum fittings but I didnt find any...I have rebuilt another c4 from my 250 73 and it had an orange or red stripe i believe..it had 2 ports..so my question is..do i have the wrong modulator on my car?Im about to go buy one and switch it out but i need to get this cleared up first..Thanks
When I had my carburetor rebuilt I forgot to mark the hoses for the modular valve shift line. I have a 73 Ford Maverick with a 250 4.1L or a i6 engine with a c4 tranny. But I need to know on the passenger side of the carburetor which port do I plug it back into or does it have multiple places it needs to be put back into I used to have a t on it for the vacuum but since had all that other stuff taken off the engine. Could somebody send me a picture on here showing me where it's supposed to go at least or tell me which side and which carburetor port is supposed to go into please.
Best I can remember on my '74 the transmission got its vacuum from the intake log. It's the metal line under the EGR in this photo.
