Another shifting question. Second gear is like a kick in the ***

Jakaru · 03-12-2007, 03:55 AM

Ok so I've posted a few times about my car troubles. So I finally found someone who knew what they were talking about and found out it was my points. Well since they were going to wear out again anyhow I figured hey, why not put a flamethrower on there and take out the solinoind (sp?) too. Of course if I had that might as well put a four barrel on there which means a new intake too. z89 from eddlebrock I think?? Well $800 in parts and $200 in odds and ends later my 65 was running once again and better than ever.

Well I created a new problem. My rpms seem to be running higher than before for the same speed. Well around 50-60 mph it shifts from first to second. If my foots not into it it seems to shift hard and it's like a kick in the pants and it speeds up a bit. If I'm into it it actually seems to shift smoother. My problem is most of the roads are 45-50 mph speed limit which means I either sit at the end of my first gear at high rpms or it shifts hard into second. Is that normal or something I should be concearned about? Is it a sign that the tranny is going bad or just an adjustment problem?

JMD · 03-12-2007, 04:05 AM

Are you sure that your vac modulator is hooked up and the vac line is not kinked?

Also, I think that the vacume modulator needs to be hooked to manifold vacume, and not to a carb port.

The way you describe the shifting, I am nearly certain that you have an issue with the modulator.

Oh,, and make sure that the vac line is not colapsing on itself, especially if you had to extend or otherwise replace part of the hose.

Jakaru · 03-12-2007, 04:21 AM

hmm there was a lot of backyard engineering done to that car before I got it. We blocked off most of the ports on the intake and what not.

Now that you mention it though I did have a tube coming up from near the tranny that was connected to a three way valve thingy that went into my valve covers and the other part went into... the intake I think. Now that tube is just sticking up from down there. Can you help me out on what to look for and where its supposed to be coming from and going to?

JMD · 03-12-2007, 05:20 AM

Quote:

ORIGINAL: Jakaru

hmm there was a lot of backyard engineering done to that car before I got it. We blocked off most of the ports on the intake and what not.

Now that you mention it though I did have a tube coming up from near the tranny that was connected to a three way valve thingy that went into my valve covers and the other part went into... the intake I think. Now that tube is just sticking up from down there. Can you help me out on what to look for and where its supposed to be coming from and going to?

Bear with me, I am not experienced with a C-4 but I think I can help!

I went out and looked at a C-6 that I have, it has a steel vacume line that runs from the back of the trany (but in front of the tailshaft section) on the drivers side. It runs up behind the bellhousing and comes up into the engine compartment and ends behind the drivers side cylinder head. This line will need to be connected to a manifold vac source using rubber vacume line between the end of the line and a manifold vac port.

This will be the only connection that you will need to make to resore proper shifting to your transmission. I dont know what else might have been hooked in with this line, if you need it you will know soon enough, but, as I stated above all that needs to be done with this particular line I am refering to now, is for it to be hooked up to manifold vac.

In research I could not find a good photo of the modulator itself, but I am counting on the c-4 and c-6 being similar in this regard.

Since you have installed an aftermarket manifold, you may find that you do not have the fittings you need on this manifold to make the connection, but you should be able to find a suitable fitting in just about any parts store. Chances are that the stock fitting from your old manifold wont fit, at least they never do for me!

Fix it soon, you transmission could be damaged by operating this harshly!

boeing747arowair · 03-12-2007, 11:19 AM

Obviously you have an issue and as stated before it is probably the vac line or the modulator itself. On the C-4, it is located on the passenger side of the transmission. Check out the vacuum line which should be hooked up at your intake manifold if that is fine, it might be your modulator valve. Do some research also on here i remember somebody having some similar trouble to this a couple of months ago! Good Luck and feel free to ask.! but don't much more time like that!

dnswwood · 03-12-2007, 11:27 AM

seems to me on my 70 the vaccum line goes from the manifold to a tree on the firewall.that tree pulls vaccum for the brake booster and the transmission as well as the vaccum lines for the heater and A/c.
Jeff

eholzer07 · 03-12-2007, 04:50 PM

I think that with you whole new set up (carb and watnot)you will have to ask someone who has a similar setup or ask the manufacturer what to do.

my77stang · 03-12-2007, 05:45 PM

vacuum hookups for dummies (i just love using pictures LOL)

put something like this....

either here, or here.....

simple as that...... and yeah, thats exactly why its not shifting properly (having the modulator unhooked)

69FECoupe · 03-12-2007, 05:48 PM

It sounds like your kick down linkage for passing gear is adjusted incorrectly. If it is, it will cause the condition you describe.

my77stang · 03-12-2007, 06:06 PM

Quote:

Now that you mention it though I did have a tube coming up from near the tranny that was connected to a three way valve thingy that went into my valve covers and the other part went into... the intake I think. Now that tube is just sticking up from down there.

69FE, that qoute kinda said it right there