C4 modulator
 

i got a replacement due to the old one being rusted to crap.. it's a blue stripe. i heard this is for high altitude compensations? and that i should get the white stripe one. i'm ahving a problem with it shifting from 2nd to 3rd quickly- before it didn't with the old one. - i adjusted the screw today and it went from the 2-3 at like 3300 to around 4000 , then i did it again and it only got to like 4100. so do i have the wrong one or what?

also.. i have a stall converter and a new valve body and the transmission you can shift manually 1-2 and it's fine, but in 2nd it will automatically shift into 3rd.. why? i can't hold it beyond what the modulator was letting me, but shouldn't it not shift regardless?

RE: C4 modulator
 

Check the vacuum and make sure the engine is running ok. You will need the right one also. I am not sure on the color code, but if itswrong, then it won't shift right. Youmay play a little more with the pin to see if that solves the problem.Also make sure the linkage has not moved.I was thinking it had more like a green stripe, but I'm not sure.

RE: C4 modulator
 

i was going to try the white stripe as its for c4's up to 72, and that one is readily available here. i'll check the hose since it's the original 67 hose and it slides on and off way too easily on the metal part to the manifold so maybe that's it also.

engines running fine, finally other than the secondaries not opening at all but that's another story.

when it's daylight out i'll check it all :) thanks

RE: C4 modulator
 

I believe it is a green stripe, it os on my 65.

The modulator won't cause it to shift if you have a shift kit.
I've had stage 2 and stage 3 shift kits in C4's and it will shift only when I tell it.

RE: C4 modulator
 

i got one listed with a white stripe today and it shifts from 2-3 super fast now and slips 3rd :\ ugh

RE: C4 modulator
 

You need to read up on what you're doing with that modulator. The factory service manual has a pretty good sectiothat is side bolted on (in lieu of push in) was used in most of the early models.