New 71 Mach 1 Owner, ~problems~ - Ford Forums

shootmymime · 03-09-2008, 19:08

HELLO GUYS,
i am a proud new owner of a 80% original 1971 mach 1, this car will be my job for the next year, restoring and fixing it to be a real classic.

so anyways, today i replaced the radiator to stock, (im going back all stock on the car BTW) and changed plugs, oil and filter.

but my main problem is the transmission, i dosnt want to shift from 1-2 and mainly 2-3,

the car is a 351C witha FMX tranny, about 177,308 miles Original.

and alot of hoses are missing or run all over the engine bay, i hear a vacuum leak could cause my transmission to slip.

so i need some help on how hoses run, and the basic on how to fix this transmission

ill include a picture of my new ride

**Big Block Ford** · 03-09-2008, 20:12

Hi you have a nice car.

I'm afraid I wont be able to tell you where all the hoses run. You will probably need a car manual to get pictures of where they run. It is correct that a vacum leak may affect your trans shifting but I would first check the transmission oil level.
This should be checked with the engine up to temp and the car idiling while the transmission is in park. Check what condition the oil is in too from what you can see on the transmission dipstick. If it appears brown or smells burnt then the transmission maybe in need of a rebuild. The oil is usually a pink or red color but may look a little clear on the dipstick.
If the level is correct then you should check under the car on the underside of the transmission for any vacum hoses that may have come off or maybe cracked or broken.

If this all looks correct then check your engine bay for any major leaks from hoses as you are worried about this.

If this does not solve your problem then I would assume your trans may need to be serviced. There are some band adjustments that a tranmission shop can do or perhaps a rebuild. At the very least your car will need to go to a shop for checking.

shootmymime · 03-09-2008, 20:29

well im a young part time mechanic at our local shop, so i do know a few things about cars, but this is my 1st carb car i have ever worked on.

yes all the tranny fluid checks out fine, and i bought some jackstands and spend a good 2 hours under the car looking for id tags,

what would you guys really say would cause my problem? what type of vacuum lines???

**Big Block Ford** · 03-10-2008, 17:47

Quote:

Originally Posted by shootmymime

well im a young part time mechanic at our local shop, so i do know a few things about cars, but this is my 1st carb car i have ever worked on.

yes all the tranny fluid checks out fine, and i bought some jackstands and spend a good 2 hours under the car looking for id tags,

what would you guys really say would cause my problem? what type of vacuum lines???

It sounds like you are mechanically minded so you will be able to check some stuff yourself. The transmissions have small vacum units on the outside of the transmission that help to control shifting. These have lines attached to them that you need to check for leakage and if you have vacum leaks anywhere else on the car that are serious enough then it will affect the trans. The units themselves may also be faulty.

Be sure the shift linkages are all working correctly.

If I was to take a guess and this is the original trans at that mileage then I would put it down to a band adjust and service needed. If you can get a workshop manual on a Mustang with service data for the FMX then you may wish to try it yourself. The oil pan will need to be removed and you can clean any filters inside which are likely clogged up now and adjust the bands to the correct settings. If you are unable to get the band to the right settings then it is likely worn out and the trans will need overhauling.

artstang · 07-17-2008, 12:51

In addition to Big Block Ford comments you might want to check the vacumm modulator valve to see if the hose is plug in or if you are getting a vacumm.