1967 POWERGLIDE TRANSMISSION

[ED #23560]

I HAVE A 1967 CONVERTIBLE THAT I BOUGHT IN 1994. IT WON THE DUNTOV AWARD AT WILLIAMSBURG, VA. IN 1990. WHEN I BOUGHT THE CAR IT HAD A HARSH DOWNSHIFT. THE SELLER TOLD ME THAT ALL POWERGLIDES WERE LIKE THAT. I HAVE NOT DRIVEN THE CAR THAT MUCH OVER THE YEARS, BUT THE HARSH DOWNSHIFT HAS ALWAYS BOTHERED ME. I HAD THE POWERGLIDE REBUILT AND CHECKED. IT SEEMS TO NOT BE AS HARSH WHEN THE CAR HEATS UP. ALSO WHEN DECELERATING, I CAN GIVE IT SOME GAS WHILE APPLYING THE BRAKE AND IT SHIFTS TO LOW GEAR A LOT SMOOTHER. EVERTHING ELSE WITH THE CAR IS AS NEW. ANY SOLUTIONS??? THANKS!

[Bob R.]

Re: 1967 POWERGLIDE TRANSMISSION

It's hard to tell without driving the car but the powerglide transmission does shift rather hard especially compaired to todays cars. MY 63 powerglide has a very noticable shift to low when approaching a light.

[Tom D.]

You're making me miss the old PG whine ...

as well as the downshift "lunge".

Tom Dingman
4889

[Joe L.]

Re: 1967 POWERGLIDE TRANSMISSION

Ed-----

Like so many other things, the "problem" that you are experiencing is VERY likely a result of a "frame of reference induced phenomenon". Folks today are used to the shifting of electronically controlled, modern day transmissions that are generations removed from the old Powerglide which was, basically, a first generation automatic transmission. Even folks that were around in the 60's often forget what these transmission were like because they've been "lulled" into thinking that the way today's transmissions operate is how ANY automatic transmission is supposed to work.

Back in the 50's and 60's, a lot of folks thought the old Powerglide was pretty great because their "frame of reference" was 3 speed manual column shift. Believe me, the Powerglide was a HUGE improvement over that for most folks.

Essentially, the Powerglide was a "low buck" automatic transmission designed for mass installation in Chevrolet passenger cars which have always been the "entry level" cars in GM's stable. The more "up-scale" cars in the GM portfolio used Hydramatic transmissions that were a lot more refined (for their day). The first Hydramatic transmission installed in a Corvette was for the 1968 model year and that was a MAJOR leap from the Powerglide used for all earlier Corvettes.

[Ray G.]

Re: 1967 POWERGLIDE TRANSMISSION

Hello;
Check for low vacuum? Should have 19-21 inches at the modulator.
Cracked vacuum hose?
Proper fast & slow idle speeds?
Modulator?
Linkage not binding and free.
Gas will build up in the vacuum line to the trans, just from fumes.

Hope that helps.
Ray

[Joe R.]

Re: 1967 POWERGLIDE TRANSMISSION

Back in the 1970s when I worked on a lot of Powerglides, I think the usual reason for a hard downshift was a defective or disconnected vacuum modulator. I suggest that you check the modulator itself and the vacuum signal that feeds it. There may also be some other things listed in the shop manual as possible causes of hard downshifts.

By the way, I presently own a 67 Powerglide Corvette, and the downshifts on my car are very smooth. In my view, the upshifts on my car under brisk-to-full acceleration are a little "too smooth" (not very crisp), so maybe my Powerglide is a bit tired. But, as Joe Lucia says, most of don't clearly recall how these transmissions behaved when they were new. I have wondered what the judges would have to say about my car's upshifts if I ever try to PV the car.

[Paul L.]

Re: 1967 POWERGLIDE TRANSMISSION

Joe,
You probably remember when these transmissions were called PowerSlide because of the very smooth L to D shift. With my 1967 I consider that normal. One solution to getting a crisper shift and lessening wear is to install a TransGo kit.

As to the original question, I do not even notice the downshifts they are so smooth.

[john daly]

Re: 1967 POWERGLIDE TRANSMISSION

On my old 71 Chevelle with a 307 and a PG, adjusting the shift band did wonders for the shift quality. It just an adjustment and torque setting on a set screw. The details are in the shop manual.

[ED #23560]

Re: 1967 POWERGLIDE TRANSMISSION

THANKS FOR ALL THE INFO!!