66Mustanger

I just had my 1966 C-Coupe C-4 trans overhauled because it was leaking fluid and all the seals were drying out. It ran great before and after, however, now I get an intermittent blue smoke with the burning oil smell after moderate-hard acceleration and braking or deceleration after passing. I am speculating that it may be the modulator valve needing adjustment. I am trying to rule out oil on the exhaust during the work and other sources. Never had this issue before the overhaul. I will be taking it back to the trans shop ASAP, but thought I would get some other input first.

boogerschnot

Where is the smoke coming from? Tailpipes/exhaust=. You got throttle happy after the install of the rebuild. And may need to freshen the motor. Check the plugs for residue

Other places=. Oil or transmission leak. Could come from the modulatorbeing bad..maybe.. but not likely. If it still shifts normally from 2 to 3 that's probably not it.

66Mustanger

Well, actually I needed to pass a very slow driver on Hwy 154 ( a mountain road) at the only available place to pass and then ran up on another tourist driving the "scary road" and had to break it down to not rear end them. After seeing the smoke, I intentionally did it again to try to recreate the event and did. However, today I inspected the engine bay and discovered that the "mechanic" that reinstalled the trans kinked the vacuum hose from the intake manifold to the modulator valve when he hooked it up. I disconnected it and reinstalled it without the kink and have not been able to recreate the event since then. So, I think that I found the problem. Apparently, a kinked vacuum hose has the same result as a bad modulator valve! I will test it some more, but I think I found the problem. Besides, what good is a spirited Mustang without spurring it up a little to get out and run? The engine sounds great and all is good in the Santa Ynez Valley! Thanks.

66Mustanger

P.S. I also discovered some trans fluid had leaked or spilled onto the driver side exhaust pipe right below the driver's seat. The smoke did not look like it was all coming from the exhaust pipe, but I could not tell while driving. Looks like it was a combination of things that caused the smoke. All good now though!