[sypderturbo007]

Hello! I just acquired a 1974 Mustang II (2.8L V6). It had not been driven in 3 years and seemed to be in good shape. I know nothing about carborated vehicles and need some help. The motor runs perfect (in my opinion). The problem I am having is the transmission is not shifting properly. I was told that the shifts are controlled by manifold vacuum. I have random vacuum nipples with no vacuum lines and I am LOST! The vehicle shifts late about 800 - 900 rpm's after I feel that it should. It also seems like the last person working on the vehicle had no idea what they were doing. I can post a picture if it would make your life easier. I just need to find out what lines control the transmission. Thanks in advance for your help.

[Fordgazm]

the vaccuum modulator valve needs replaced or adjusted . Thats on the side of the transmission . Hope that helps you

[sypderturbo007]

I replaced that yesterday and it shifts much better. You were right, apparently there was a hole in the diaphram and it was sucking up tranny fluid into the vacuum lines. The only problem is that it still isn't right. It doesn't fluctuate back and forth anymore but it does jump gears sometimes. For example: I am driving down the road at 30mph, the tranny is in 3rd gear. If I give it a little gas, ie. less than 1/4 throttle it will downshift into 2nd and then drop back into 3rd. Before it used to jump back and forth, back and forth. We thought the kickdown was out of adjustment. Not the case, it actually isn't even hooked up. Apparently somewhere along the line the c-clip popped off. I am getting another one this weekend. Would that be causing the problem?

[BullRider]

You guys are so helpful. Thank you, this article just saved a motor from being tooking out, and money being spent.