C-6 Vacuum Regulator

[big van]

My van is at the shop getting the tranny done and they can't get it to shift right. Turns out the PO of my van had a 91 motor that use to have a E4OD behind it put in the van. So they bolted it to a C-6 and put it in. The E4od was elec. & the C-6 is vac. They ran constant vac. to the C-6 and this burnt it up. So I'll be putting a vacuum regulator on tomorrow when the Ford garage gets it in. It bolts to the IP. But other than that I'll have to figure it out as I go. Any body have advice? Anything special I should know about? Does this have anything to do with the throttle kick down, cause mine never worked. Thanks for the help. Matt

Here's a diagram the parts guy at ford gave me. The circled part is the regulator.

 

[Todd C]

If it had full vacuum all the time it should have up shifted at low rpms all the time (like you were accelerating very slow, light on the pedal). The VRV (vacuum regulator valve) just mimics the manifold vacuum you would have on a gas engine for the C-6 tranny. There are specs for setting the VRV, but I don't have them. Setting it incorrectly, (or not having it installed ...) can damage the tranny.
You should probably change the vacuum modulator on the tranny just to be sure its good, and the right one for a diesel.
Check to see if the kickdown rod is hooked up to the injection pump correctly also. On the last bit of travel of the accelerator lever on the injection pump, it will push the kickdown rod to force a downshift. Having that disconnected completely may be ok, but if its stuck in the downshift position, its bad for the tranny also.
Good Luck
Todd

 

[big van]

The vac modulator is green stripe. From what I'm told this is correct. It did always seem to shift early and I don't think I even have a kick down rod but remember reading some guys remove it any way. Thanks, Matt

 

[Diesel JD]

That was a stupid thing of them to do. At leastthey're paying for it. I burnt up a C6 that way too, and I do think its the only way to kill them is to put constant or near constant vaccum to them. Really you have 2 modulators on a C6 though, there is the modulator with a pin in the vaccum lineand back of the tranny. Its a cheap $3 part but its absolutely essential, and the pin is as well. Then there is the VRV which is on the injection pump. I bet they left the modulator out or the pin or used the wron one. Constant vaccum where the VRV should be for temporary purposes won't hurt anything unless youa re working the trans hard. Constant vaccum anywhere long term will kill it good though..blow out seals, burn hard parts, the whole 9 yards. So you want to get the VRV, they aren't cheap, but they are a neccessity. The specs can (or could) be found here www.intellidog.com/dieselmann Good luck ,
J.D.

 

[dbensen]

Yes, the modulator is the green stripe one. The setting for the VRV are in the shop manual. It is simple on a truck but you need like five hands when you do a van. If you need the procedure I can look it up for you. I did not find the shift points where I liked them when I set the VRV to the stock location but I would still set it to specs. for a good start. On the vacuum modulator there is a screw that is accessible if you pull the vacuum line off. I have no idea how many turns until it bottoms out or falls out in your hands but backing it out allows it to shift earlier, turning it in shifts later. I'm almost positive on the in out thing. Just count your turns in case you want to go back.
good luck,
Doug
'86 F-250 4x4
'89 E-250 ATS turbo

 

[typ4]

You can run a c6 with out kickdown rod and not hurt it because that is all it does. Set the vrv valve about the middle and test drive it and as previously stated the modulator is a little adjustable for fine tuning.
Have fun'
russ

 

[Diesel JD]

You really don't need the kickdown rod, just remember to downshift if you are climbing a big hill and the truck is struggling, or something of that nature. It just kicks the transmission down when you have near full throttle under load. Just make sure you get the modulator right and have the VRV at least where you can feel 2 distinct shifts; 1-2 is and should be kind of soft and subtle in stock settings but you should def. feel 2-3. The way direct vaccum burbs these things up is that you 'stack shift' or run right over 1st and right into drive(3rd) creating a lot of heat and eventually burning parts and blowing seals.

 

[Agnem]

When I built the Moosestang, I never put the kickdown rod on it, and can't say I'd ever see a need for it. Playing with the VRV is frought with frustration. My trans made some really nasty noises when I tried different settings and ended up putting it right back to where the book says it should be. My second to third shifts were really lathargic in hot weather until I installed an auxiliary cooler.