[Mustang Man 65]

So, I have my very first question My 65 Mustang that I currently bought, has a 3 speed Auto Tans. Do these typically run at high RPM's? I took it out on the freeway the other day and it seemed like I was already at 5000RPM's and only going around 65 Mph

[cindys_sn95]

it depends on what gear is in the rearend. get a tach, that way you will know what rpm it is turning.

[Mustang Man 65]

Originally Posted by cindys_sn95

it depends on what gear is in the rearend. get a tach, that way you will know what rpm it is turning.

Thanks, I do have a Tach already. I guess I need to find out if the gears in the rear where changed

[cindys_sn95]

what was the rpms REALLY at when you were running 65?

[Jonk67]

Here are some handy calculators, figure out your tire height then you should be able to get a close idea of what gears you have based on tire/Rpm/speed and trans. 3rd gear should be 1:1 ratio.
Randy's Ring & Pinion. Calculators.
Jon

[Cusp]

Originally Posted by Mustang Man 65

So, I have my very first question My 65 Mustang that I currently bought, has a 3 speed Auto Tans. Do these typically run at high RPM's? I took it out on the freeway the other day and it seemed like I was already at 5000RPM's and only going around 65 Mph

Wow! Are you sure the tach it set for the correct number of cylinders? If its an aftermarket tach, I would check.

[jspagna1]

Something is definitely off? I have a C4 with 3.55's in the rearend and I am at 3 grand at 70MPH on the highway.

[Mustang Man 65]

Originally Posted by Cusp

Wow! Are you sure the tach it set for the correct number of cylinders? If its an aftermarket tach, I would check.

You know, I'm not to sure. Its a tach by Evil, not sure if there any good.

[429ragtop]

are you sure the c4 wasnt in 2nd gear?

[Mustang Man 65]

Ok, so I went on my lunch break and payed close attention to where my car was shifting at and this is what I saw based on my tach and mph.

1st to 2nd Gear Approx 15mph @ 2000rpm
2nd to 3rd Gear Approx 20mph @ 2700rpm

I dont understand whats going on? Is there a 4th Gear?

[Jonk67]

So your 2nd gear lasted from 15mph to 20mph?
If it's a C4 I'd probably start by getting the filter and fluid changed.
Have you checked the fluid level while in park and running? Trans. vacuum modulator could be bad also or 1 or both of the rubber lines to the vacuum is old/split. I'd start with those. Only 3 gears in a C4, AOD w/4th didn't come out for >10yrs. later IIRC.
Jon

[Mustang Man 65]

Originally Posted by Jonk67

So your 2nd gear lasted from 15mph to 20mph?
If it's a C4 I'd probably start by getting the filter and fluid changed.
Have you checked the fluid level while in park and running? Trans. vacuum modulator could be bad also or 1 or both of the rubber lines to the vacuum is old/split. I'd start with those. Only 3 gears in a C4, AOD w/4th didn't come out for >10yrs. later IIRC.
Jon

Yes, my 2nd Gear only lasted up to 20mph, where should it be shifting at? I just put Tranny fluid in so I don't think its that but not sure about the other stuff.

[67ragtopStang]

Originally Posted by 429ragtop

are you sure the c4 wasnt in 2nd gear?

I think 429ragtop has it nailed. In the '65/'66 C4's, Drive is the second notch after Neutral (the dot). You probably were in the first notch after Neutral.

In '67 and later cars, the first notch after Neutral is Drive.

[thetvirus]

How could drive be the SECOND dot after neutral? How could you even manually shift the car? On my C4, it goes N, D, L2, L1, and you can start out in L2 second gear, owners manual says for slippery conditions... Oh is there any harm to manually shift a C4? I do it sometimes and shift a 4100 rpm L1 to L2 to Drive. I use L2 to slow down sometimes cuz manual drums are terrible, Can't use L1 to slow down cuz it actually squeals the tires, some kind of shift kit in it...

[jspagna1]

The 65-66 Mustangs with the C4 Transmissions were the "Green Dot" transmissions. You moved the shift lever to the Green Not position and the trans shifts through the gears itself.