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Discussion Starter #1
I have a 65 mustang i6 200ci 3speed auto with a few issues. First off the car shakes at around 20 mph is seems like in between 1st and second gear. I'm also getting the hard clunk when shifting from or into reverse. Also when cold the car will slip out of first gear.

Also I'm getting valve knock at high rpm. I took the heads to a head shop to replace the valve rubber and told him about the problem. He didn't see anything wrong with the head.

Also When I start the car up and when I'm giving the car alot of gas I get a rattling sound coming from what sounds to be the carb. I did get a new re-manufactured holly 1bbl. I have the pertronix electronic ignition and I thought my timing was correct.

any help would be greatly appreciated.
 

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Your rattle is likely detonation or spark knock.
At 20 mph your C4 should already have shifted into at least 2nd gear. It may need to be serviced. (fluid change and band adjustment)
The clunk, if extreme, is probably u-joint or gear wear in the differential.
 

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I've done a fair amount of work on C4 trannys and what you're experiencing is morning sickness. Since you say it acts up when cold, the pressure plate that is used to apply clutch plates is cold and the worn seals aren't making contact. The steel drum and aluminum pressure plate heat up, and since aluminum expands at a higher rate, "grows" enough to allow the seals to contact the drum, making the shift. To fix this it needs new seals. These are inside the tranny so don't let someone talk you into changing the front and rear seals, they just keep fluid from leaking all over. The seals you need, plus new clutches and bands, and gaskets, shouldn't cost more than about $125 (depending on where you go). Find a transmission parts house nearby and get a "soft parts" kit. You can do the job yourself if you are comfortable with a torque wrench, can work in a clean environment (very clean) and get a decent manual with specs and drawings. There are several on the market. DO NOT use any product that promises to seal up a tranny, those will swell the seals and they will get soft and wear very rapidly. You'll end up having to rebuild the tranny anyway but you'll have more of a mess with the "fixit" fluid in it.
 

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My '66 does the same damn thing, sticks in 2nd unless I get going fast, but then shifts just fine when it's warmed up. Also, it is slow to engage in drive, and really bangs into reverse. It's annoying.

The transmission was rebuilt in '94, but the car sat a lot, I'm guessing that hastened the troubles.

Or do the C4s always bang into reverse?

My u-joints are new. It's not a huge problem, but it's annoying.

Michael

 

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Try Replacing your Filter and the tranny fluid and see if that improves things.
 

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This does not sound like a transmission problem to me but try adjusting the bands and changing the fluid.
My guess is that you have bad cam timing or vacuum issues.
C4s will bang into reverse (so will any auto) if the idle is too high or if the bands are too loose.
 

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Discussion Starter #7
Thanks guys. I'm going to take the car into the speed shop and have them take a look at the tranny and the spark knock. thanks again for the responses.
 
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