emttrevor

Okay Ill start at the beginning- Just had c4 rebuilt drove it for about 10 miles and then it failed to change gears automatically. It would change ok manually but not from drive it just sat there in third gear. Thinking the worse of the transmission shop I called them, guy was great told me to bring it back this coming Monday and he'll check it out, rectify the problem for free etc. Well in messing around with it today I noticed that the motor wasnt performing too well either.....I found that my vacuum advance on my distributor was screwed ..... replaced the distributor with new one now the tranny shifts just fine again. If im correct and I dont have a ghost from owners past then maybe the vacuum was leaking through the distributor somehow as in the diaphram was fractured and drew the vacuum away from the tranny? Is that even possible? lol
So my question is am i right and thats what happened or was it something else that may have either rectified itself or what...



67 stang, 302 roller motor, e303 cam, rpm heads and intake, 670 street avenger carb, flame thrower dist', c4 tranny and 8" 3.55 gears

JMD

Sounds reasonable to me, a loss of vacuum will cause the C-4 so shift improperly, especially if the trans modulator and distributor are plumbed on the same vac line....

emttrevor

seperate vac lines all together thats really what made me wonder if it was right just never heard of it happening before

JMD

In a low vac condition the modulator will prevent the transmission from shifting until the the RPM's are way high.

I think you probably fixed BOTH of your issues when replacing the vac advance.