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I have a 1964 Pontiac Parisienne, the Canadian one i think. The car has a 283ci Chevy small block fitted and has a GM transmission, column shift with D and L forward gears. I dont know what type the tranny is, but im told its an early cast iron GM hydraglide. When i collected the car about two weeks ago it moved through all the gears fine, up and back down again;however for about five days now it wont upshift. The result of this is the car is doing about 4000rpm at 35mph.A mechanic thought it might be the pipe from the vacuum unit on the side of the trans to the inlet manifold, however upon inspection this pipe wasnt fitted and never has been! Fitment of a pipe from the vacuum on the distributor to the chamber on the tranny has made no difference. Fluid level when COLD is at the full mark. Do you have any suggestions please? Thank you very much, Richard
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Yes, there was no "Parisienne" in the US (except for a show car of that name).
I'm going to have to do a little guessing here, as I am unfamiliar with the Canadian models of GM cars. I beleive that the 64 Parisienne used Chevrolet mechanical parts, so very likely the transmission is a "Powerglide" transmission, which was used in US made Chevrolets. 1964 was a transition year between two models of Powerglide, but from what you say, yours has a vacuum modulator, so I'm pretty sure you have an aluminum case Powerglide.
This really doesn't make much difference to you, unless you have to remove the transmission. The cast iron transmission is backbreakingly heavy, the aluminum case unit is only back-straining!
To start with, let's verify that you have a Powerglide.
To verify this, start the engine and put the car in park. If you hear a definite "whine" from the transmission, it is a Powerglide. (There was no "hydraglide", at least in the US that I ever heard of before). Pontiacs in the US used the Hydramatic in 1964.
Anyway, if it has a vacuum modulator, it certainly does need to be connected! There should be a vacuum connection to the modulator from the intake manifold, and this will definitely affect the operation of the transmission if it is disconnected or missing. So step one is to reconnect that vacuum line to see if it helps. If it doesn't, you may have a bad vacuum modulator. You can check this for yourself by applying suction to the vacuum fitting on the transmission. If you feel that there is no resistance to your attempt to suck on it, the modulator has failed and must be replaced. These are cheap and easy to change, so do that as a first step. I don't have much hope that it is going to cure all your problems, however, because the vacuum modulator controls the "kickdown" function, not the upshift.
You also need to verify that the throttle linkage is set correctly. This is the rod (not vacuum line) that goes to the driver's side of the transmission. (It is the rod that moves when someone steps on the accelerator, it is not the rod that moves with the shift lever on the steering column.)
To properly adjust the rod, have someone hold the accelerator pedal to the floor, then adjust the rod so that the lever in front of the firewall is just barely off it's stop, and the transmission lever is all the way against it's internal stop.
When the car is warmed up it may shift better (this is typical for a worn transmission), but if it is still not satisfactory, you need to take the car to a transmission repair shop and get them to diagnose it.
Of course, you should make sure that the shift lever is correctly adjusted so that it is really in "drive" when you think it is, and not in "Low".
If this isn't enough information, post a "follow up" message and I'll try harder.
Dick
Thank you very much for that Dick.
The transmission LOOKS like iron to me and not aluminium, however i'm not sure about that, it could well be aluminium. When i say it has a vacuum modulator, i assume thats what it is....Its a small metal cannister on the passenger side of the tranny and has a take off which looks like it should have a pipe on it...The thing is, i'm not sure that there was ever a pipe connected to it because there is no place on the intake manifold to connect to. It is now connected to the vacuum pipe on the distributor/carb but to no avail. When i was under the car yesterday i noticed that the lever arm on the tranny (on the drivers side above and forward of the actual linkage from the column)is not connected to anything...However, someone suggested this was only the kickdown lever and had nothing to do with the upshift!!! If as you say, that is supposed to be connected to the throttle, then that is obviously where my problem is, but i still cant figure out why it was working fine a week ago and now doesnt work. (i feel if the rod had been connected and had fallen off i would have heard/noticed it) So basically i suppose what i am saying is, without that lever being connected to the throttle are you saying that the tranny simply will not upshift? Sorry for the long winded reply but i want you to have all the facts!!!! Thanks again
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You describe the vacuum modulator exactly; it is very important that the vacuum line be hooked up to the intake manifold vacuum (NOT the ported vacuum, where it is connected now). Operating the transmission with this disconnected (or if the modulator has failed ) will result in rapid and expensive failure of the transmission.
You'll have to put a vacuum hose on it, suck on it to make sure it is still airtight, then route the hose to a source of intake manifold vacuum. There will be one somewhere on the carburetor base, or on the hookup for the power brake unit, or the connector to the PCV valve, just keep looking until you find it. Someone may have plugged it off with a pipe plug, but I assure you, there was a line there, and it must be restored to operation or you will have an expensive repair soon!
Now to your real problem: Yes, the rod that controls the shifting of the transmission is very important also, and I am virtually certain that its falling off has caused your current problem with upshifting. If you are lucky, you can just put it back on and secure it with a cotter pin or the like, and your transmission will be restored to normal operation. You should check that it is still adjusted properly (as decribed in my previous response). In re-reading your latest note, I see that you have not yet found the rod. It may be laying in the road somewhere, but usually these stay attached on at least one end - I hope you can find it. If you can figure out where both ends were connected, perhaps you can make one from a piece of brake tubing, properly bent to miss obstacles etc, with the ends cut off and flattened and drilled to accept the fastenings on the throttle linkage and transmission. It is only important that as the throttle gets to full acceleration, the lever on the transmission is pushed as far as it will go (there is an internal stop in the transmission). The direction in which it is pushed should be obvious from inspection of the linkage, but if not, I will try to find a drawing of the rod in place to help you.
As I recall, the throttle linkage to the transmission is operated by a second rod that comes back toward the firewall from the top of the rotating flange on the carburetor which operates the throttle valve inside the carburetor. (the "first" rod is what I am calling the rod that comes to the carburetor from the foot accelerator pedal). These two rods move in oposite directions. I believe the upper rod is the one for the transmission control, and it should have a return spring on it, pulling it toward the front of the car. This rod goes to a relay device which rotates on an independent axis at the rear of the engine, and in turn pulls and pushes on a rod that goes to the "throttle valve" lever of the transmission. My recollection is that this lever is toward the front of the transmission, and I believe it is pushed "down" when the accelerator is floored. If I am describing what you see, then make sure that the rod is pushed all the way down against the internal stop when the acclerator is floored. Then the transmission should shift right.
If these parts are missing, you are going to have to make or find replacements, and you must not drive the car without them, as you will damage the transmission rapidly. The throttle valve is used to adjust internal pressures in the transmission - not having this function will cause bands to wear and slip, and probably is what is causing the transmission to fail to shift.
You didn't mention whether or not you heard the "whine" in Park which verifys that this is a Powerglide - I hope that we are working on the right transmission here - but from your description of the vacuum modulator and the throttle control rod, I think we are.
One thing you could do for a quick check is to note the current position of the throttle valve lever on the transmission, and with a rubber band or spring, move it to the other end of its travel, then try driving the car. I'm betting it will now shift - although the shift pattern might be a little strange because the accelerator isn't moving the lever the way it is supposed to move it, at least you will learn that the problem is with the missing link.
Please let me know what you find out, I'd like to keep track of this one.
Dick
Thank you again for that Dick.
I've had another look all around the inlet manifold and the carb base to see if i can find a source of vacuum and there defintely is not one anywhere on either of those. When you say the PCV valve, im not entirely sure what you mean...And i presume by the power brake unit you mean the brake master cylinder coming out of the bulkhead on the drivers side under the bonnet? I am really lost as to where this source is. I understand what youre saying, there must be one, but i just cannot find anything!! The only take off on the carb base is for the vacuum pipe which goes to the condenser on the distributor.
A few days ago i did try tying a piece of cable around the throttle lever on the transmission so it was against the internal stop (i think i tied it so it was pulled back and downwards towards the rear of the car)and then drove the car to see if that did anything but there was no change. Perhaps i should have tied it the other way? The lever has a little ball connector on it so i'm fairly sure it should have something on it. I'm presuming that without the vacuum line it will not upshift anyway?
I am at a loss to explain why it was working before as it seems highly unlikely that both the vacuum pipe and the throttle lever have fallen off. You said that you may be able to find a drawing of the rod in place, it might be helpful. I am sorry to be a pain!!!!
AnswerI did locate a very poor quality picture of the carburetor and transmission control linkage, but it isn't going to help you much because it is very indistinct. Actually, my description of how it operates is pretty close to verbatim from the picture and the text. I found this in the 1965 "Motor's" Auto Repair manual. The book is 41 years old and the paper is brown with age, dirty and torn, so I don't really think it would survive trying to get a picture of it for you. Tieing the lever in the position you mention is the direction that would prevent an upshift, because it would tell the transmission that the driver is holding the gas pedal to the floor - so I'm not surprised that the transmission isn't shifting. Try tieing it in the oposite direction to see if that makes the transmission shift.
Dick
