67 Transmission Troubles

robbz28 · May 8, 2010

Alright, I need a little help, I have googled this problem a bit and just need some fresh input. My transmission worked great before I pulled it out and rebuilt the engine. It sat on the floor of my shop for probably 3 months without any fluid in it. I put the engine and transmission back in and put a new filter and fluid in the tranny. Now it won't shift out of first. I checked my vacuum line and its in good shape, and my fluid levels are proper. Could it be the vacuum modulator itself? Any ideas, im not very good with transmissions. Thanks.

D.Hearne · May 8, 2010

I'm assuming you have a C-4. right ?. If you do, when you put the engine and transmission back together, did you have any difficulty getting them together ?

robbz28 · May 8, 2010

I did have trouble at first, but i never got it bolted together completely when it was difficult, i repositioned the torque converter and it bolted together like a dream (I put it together outside of the car and slid the engine and tranny in the car as one unit). And yes, its a C4.

robbz28 · May 8, 2010

Just wanted to add, that park, neutral, and reverse work great, just stays in first, i drove it down the road to about 30 mph and it would never shift out.

D.Hearne · May 9, 2010

I'm not too much on automatics, just wondered if maybe you busted the front pump gear bolting the engine and transmission together by forcing em. The only thing comes to mind otherwise is the vacuum modulator isn't working or it's low on fluid.

woodsnake · May 9, 2010

Can you shift the transmission manually from 1-2-3?
As I read the post, it won't shift out of first, when left in drive, is that right?

robbz28 · May 9, 2010

I don't think I busted anything....like I said, i never got it "tight" when it wasnt on there right as soon as it started getting difficult to tighten I backed off and re-mated the torque converter, then it bolted together properly. And I did not check to see if it would shift manually (duh), but I am going to check that today, I am also going to blow some air through my vaccum modulator line and make sure it is clear. Most posts I have read that are having issues like mine are modulator related, but I will check again, also some mention shift linkage, though I think I have mine right, I will triple check that. i will try to get to that this afternoon if my wife don't keep me doing the "mothers day" thing all afternoon...

robbz28 · May 9, 2010

Alright, i have some input for you guys, I checked the modulator line and it looks like its all ok, I also checked the linkage and it appears to be OK. I took the car down the road at it will shift from first to second manually, but when i put it back in 3rd it shifts back into first. I am thinking that my modulator may be bad.....or a valve could be stuck? It did sit on the floor of my shop with no fluid in it for 3 months....anyway, any help is appreciated, thanks.

D.Hearne · May 9, 2010

Might have got some "critters" in it at that time. Lots of those in Lousiana. When was it last rebuilt ?

robbz28 · May 9, 2010

its possible that there might be some trash in it....but i really don't know where and how....as far as a rebuild goes, i dont know that either, not since ive owned the car, but it was doing so good, and the fluid looked good when i bought the car and it wasnt leaking, so I didnt mess with it.

woodsnake · May 9, 2010

"when i put it back in 3rd it shifts back into first."

that doesn't sound right. I don't know what would cause that to happen.....

robbz28 · May 9, 2010

Well, its not a manual valve body, so putting it in 3rd it thinks its in drive and bumps back down into first, im sure its a line pressure issue, and once again its probably because either the modulator has a hole in it and its not operating the rod to allow the fluid to shift the car automatically, or the valves are stuck....im NOT a transmission man, but by the end of this ordeal it seems I will be...

robbz28 · May 9, 2010

Alright, i just read a post in another forum somewhere that may have the answer to my problem, going to give it a try tomorrow, but if any of you have any comments, please feel free. I added a 4 bbl holley and intake (originally 2bbl ford) and when i hooked the vaccum line back up I hooked it up to one of the lower vaccum ports on the carb. The other post said that this signal is not constant enough and that it needs to be hooked up to one of the ports on the runners (which is where the factory had it). Soooooo, I will be giving that a shot tomorrow afternoon.

D.Hearne · May 10, 2010

Any of the vacuum ports on a Holley base plate will give full manifold vacuum. When you swapped carbs, did you hook up the kickdown ? If you did, then that may be the problem as the position of the throttle lever relative to the intake has changed, thus throwing the adjustment out of whack. Just a guess, but it's more likely than the vacuum signal.

robbz28 · May 10, 2010

Well, I assumed the same about the vaccum ports beneath the throttle blades, but its worth a shot ya know? I adjusted my kick down, cable, so i really don't think thats the culprit. I am just going to go down the list, but refer to this thread to see if anyone has any new suggestions. a) relocate my vaccum source b) new modulator c) check for stuck valves....after that if it's not working i guess I will have to yank it out and take it to a shop...

D.Hearne · May 10, 2010

If you were closer, there's a guy down here who's an ace when it comes to C-4's. PM sent to you.

robbz28 · May 10, 2010

Thanks for the info guys, but it was the modulator. I got one from autozone for 11 bucks, put it in there and she shifted properly, I was so excited, thanks!

D.Hearne · May 10, 2010

They have an Autozone in Epps ?

robbz28 · May 10, 2010

Hah...good thing they don't or I would be more broke than I already am. I work in rayville, which is about 20 miles west of epps, and the autozone there didnt have one, but a store 20 miles north of where I live (oak Grove) did have one....soooo i just drove on up there, i had to know, lol

woodsnake · May 10, 2010

Nice! I'm always glad to hear it is the cheap and easy fix, instead of, "back to the machine shop".....

67 Transmission Troubles

robbz28

Member

D.Hearne

New Member

robbz28

Member

robbz28

Member

D.Hearne

New Member

woodsnake

robbz28

Member

robbz28

Member

D.Hearne

New Member

robbz28

Member

woodsnake

robbz28

Member

robbz28

Member

D.Hearne

New Member

robbz28

Member

D.Hearne

New Member

robbz28

Member

D.Hearne

New Member

robbz28

Member

woodsnake

Similar threads

67 Transmission Troubles

Member

New Member

Member

Member

New Member

Member

Member

New Member

Member

Member

Member

New Member

Member

New Member

Member

New Member

Member

Similar threads

Privacy & Transparency

Privacy & Transparency