So I’ve recently bought a 73 f100 custom with 240 straight six and 4spd manual on the floor and it shifts fine and everything , everything sounds good except when you get up about 25/30+ MPH and it starts making a “ticking”? Sound , I talked to my dad and he seems to think it could be a broken tooth on the transmission, any other ideas of what it could be ?

 

Impossible to tell with that information but there are a few things you can check.

If you're stopped and you rev the engine to about the same RPM do you get the same noise? if so it's the engine, if not it's something else.

Could be valve train noise, or an exhaust leak but they're normally worse on acceleration. a missing gear tooth would be about my last suspicion.

 

I have to ask these questions...meaning this is what I would try to get a little more info on that sound.
So just where do you hear the ticking sound? From what seems like the trans hump?
As you set in the cab on the driver side.
Widows up or down make a difference?
Does your passenger hear it?
Does if go away if you go faster that 25/30?
If you go to 25/30 and hear it and speed up and it goes away, does it always come back at 25/30?
Does is go away if you (let of gas) push in the clutch (leave in gear) and coast?
Does is go away it you put it in neutral?
Clutch in still hear it?
Clutch out still hear it?
Or only under power, in gear with the engine putting power to the drive line?
Can you get some one to ride in the bed and see if they hear it? CAUTION I think that is illegal in some states if you are under 18?

 

Does not make noise while in neutral reving engine , other stuff I haven’t tried yet , oil is is at correct level also

 

Try putting the rear up on stands with the tires off the ground and run the truck. Have someone go through the gears while you try to isolate the noise.
I just went through this with my truck. I would have sworn that i had a bearing out in my transmission. It was a bad wheel bearing in the rear.
john

 

Checking stuff under the truck now , u joints seem ok , started looking at the exhaust and is it normal for it to just be resting on top of the frame? It makes a similar noise if you shake it against the frame but idk if would do that if I was driving

 

That's a thump, not tic. U joints chatter.