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Discussion Starter #1
Hey all! This is my first post on these forums, though I've been researching and lurking for the past three weeks since I bought my '66 coupe.

Here's my situation. I bought the car without taking it to a mechanic (rookie oops!) because it ran so well during the test drive and looked so good for the price ($4,500). It shows about 130k miles and had an amateur restoration about 6-10 years ago. I bought it from the second owner (supposedly) who didn't seem to have any info on it. It's got the stock 289 2V and C4 tranny.

I spent the last few weeks doing some cosmetic work on it (new woodgrain, cleaning the carpet and patching the floor pans). Yesterday I met my brothers who are also muscle car enthusiasts (78 TA's) at a restaurant about 30 miles away. The Mustang made it there and back with no problems, except that I noticed that the oil pressure was a bit lower than I remembered.

This morning I looked under the car to find a large puddle of oil on the cardboard. Prior to that it had only leaked a few drops here and there. Also, a smaller puddle of tranny fluid was just behind the oil. My father accompanied me to the restaurant yesterday and suggested that the motor seemed to be revving too high, possibly because it wasn't shifting into 3rd gear. Also, I checked the puddle of oil, and it seemed very dirty and grainy, so I decided to take it to the quick lube. On the way, the oil pressure dipped all the way down to the line just above the "L". After the oil change, the pressure was only a bit higher.

My brothers are suggesting that I take it to our family mechanic to pull the motor and tranny to have them both rebuilt. I bought the car to be my daily driver for the few months of the year that I am home (I live abroad most of the year). I want it to be a mostly stock, classic car, not a muscle speedster. What would you all suggest I do for the rebuild? What upgrades would you suggest? Since it's a daily driver, I'm concerned about mileage, but not overly so. I realize that it's 44 years old and won't ever be economic on gas.

Sorry for the long post and I appreciate in advance all of your advice!
 

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Welcome to the forum and congrats on the 66 coupe.

I would suggest first that you have the oil pressure checked with a manual gauge. Is the engine making any noise? Rattles, ticks, knocks, other? After having the oil changed is it still making a puddle of oil? Can you tell where the oil is coming from?

As for the trans - you need to verify for sure whether you have all three gears or not. Start by checking the fluid - the car should be at operating temperature in park.
Next - start in low/1st gear by placing the shifter all the way back. The car should take off and have plenty of pep and wind out pretty quickly. Next you can slide the shifter forward one click and let it engage second, you should feel a shift and hear the engine rpm drop. Next slide the shifter forward again into drive and you should feel it shift again into third.
This should tell you if you have all three forward gears or not.
 

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I can't say i know what the problem is for sure, but yanking the motor and tranny and having them rebuilt seems a bit excessive just for a couple of leaks. I'd take it in and have it looked at if you don't have the expertise to do it yourself. It could be something like a rear main seal, which would probably cost $300-400 to fix, or something as simple as a $20 leaky tranny pan gasket. Just my 2 cents.
 

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Have a cylinder compression check before even considering an engine rebuild. Agree with Mako on the oil pressure check and the tranny check. The rear main bearing seal could be the cause of the oil leak. Don't just assume the engine and transmission need rebuilding until both are checked out.

Doug
 

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Discussion Starter #5
Thanks for the advice! I did forget to mention the the tech at the lube shop said that my "main is seeping" and the transmission pan is leaking. I did take it up to highway speed, and when I shifted between the two drive gears above the "L", there was no difference at all.

Could a leaking main cause a drop in oil pressure? All fluid levels were full and no more oil was on the floor this morning.

Is there anything simple that could be causing it to miss the third gear? Something out of adjustment?

Thanks again!
 

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D2( green dot) shifts 1-2-3. D1 shift 2-3. So at highway speed ( 45 and above) they will feel the same ( 3d gear). Slowly start out on D2 drive and lightly accellerate to feel the shifts: 1st to 2nd 15-18 mph +/- 2nd to 3d 35 to 40 mph +/-. you should feel them. There are adjustments on the modulator, but don't mess with it yet.
 

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Suddenly leaking a lot of oil is almost certainly the rear main seal but it could be the front or rear seals on the intake manifold popping out of there.

Also, try putting in some STP (basically a really thick oil) and see if the oil pressure goes up. If so you have some really loose tolerances in the motor and a rebuild is in order.
 

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The ice finally melted so I was able to get it out of the garage for a test drive. When I started it up in the garage, the oil pressure gauge went all the way up to half. When it warmed up a little, it dropped back down to it's usual resting place about 1/3 from the bottom. After I drove it around for about ten miles or so, it gradually dropped back down to the leftmost line. There was no evidence under the car of further oil leakage.

While I was out I also took it to a large parking lot to test the tranny. I did find out that it does have all three gears, it's just that it shifts so quickly that I didn't notice before. Under normal acceleration, it shifts into 2nd at around 5-10 mph, then into 3rd at about 20 mph. Also, one time when I was slowing down to a stop, I manually downshifted into 'L' at around 10 mph, and it took a good 3-5 seconds to actually make the shift. Do you think everything is just out of adjustment?

I'll be taking it to the family mechanic this Saturday to get it thoroughly checked out. I just wanted to get an idea what's going on first. Thanks again!
 

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Keep in mind this is not a new car. Unless you park on white carpet or spotless white concrete chances are a few drips from the engine,tranny or PS is probably harmless. When I bought my 68 Stang is 1977 the engine and the C4 tranny leaked a little, today34 years later the leaks are about the same. The 289 runs great, the C4 is still strong as new, neither has had work done on it other than maintenance.
 
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