powerglide shifting

[dab67]

I asked these questions a while back and for some reason can not find where I put the answers so here I go again

Is there a correct upshift speed or rpm for a the  powerglide from 1st to high and is there a proper downshift when you want to pass someone or get onto the freeway? Does it matter what gear you have in the rear end? (I have a 3:03)

Thanks  dab67

[dab67]

  I errored, I have a 3:08 gear in the rear end not a 3:03. Sorry!!!!!!!!!!!!!!!

[JohnZ]

All of the '67 Camaro Powerglide upshift and downshift points/speeds are shown on page 7-35 of the 1967 Chassis Service Manual; if you don't have one, you should get one - the car is 40 years old, and no place you take it for service will have one. All the vendors have them.

[dab67]

JOHN:

Thanks, I have the manual, I saw that page. I guess I was asking the question wrong. I did not see (I'm blind) where in the manual it shows how to adjust the powerglide to shift properly. Looking at the tables, I should be able to step on the throttle at around 55 or so and feel the tranny kick down into 1st. I don't feel that.

dab67

[lakeholme]

I've got the same problem... Even after adjusting the kickdown rod as far as it would go, the passing gear will not kick in.  It seems as if the rod itself is too long.  (In my case, my motor, etc. is a mutt, but it runs fine.) I had A mechanic look at it, but he couldn't get it to work.  I'm going to take my 68 service manual to my FAVORITE mechanic and see what he can do. 

[dab67]

And that is why JohnZ is one of the Guru's here at CRG. He gives you the input on how to solve the problems. I know two shops I have talked to regarding my "glide" gave me two different opinions on how the "glide" should function. I'm not even sure I have all the correct linkage or if I do, if it is set-up correctly to do the job. Once I find in the manual how everything should be set-up and adjusted I'll take this to the shop I feel most comfortable with and let them have at it.!!!!!!!!!!!!!!!

Keepin on Truckin!!!!!!!!!!!

dab67

[lakeholme]

I'm a little mechanically "blind" myself.  Everything except the passing gear does seem to shift properly.  (I actually thought my "glide" was shifting into high too quckly, but the chart showed me it was right in the range.) I suspect it is in the linkage, too.  It all looks sort of thrown together.  If nothing else, I'm going to ask the shop to tighten everything up.  Next sunny day, I'm going to put my manual under my arm and see what they can do.

I'd love to know from John or anyone else if this is a common problem for powerglide.  I've owned and driven half a dozen cars with the "glide" but never seen this.

[dab67]

this is my first "glide" always had 4spd. Old bones mean changes!!!!!!!!!!!!!!!! I believe my shifts correctly also except for the downshift when I get on the throttle so I have the same concern. I am going to buy a book on rebuilding and adjusting the tranny and bring it to my mechanic so it is done correctly. Like I said before this is the place to get the help and directions to do things right.

Good Luck!!!!!!!!!!

dab67

[JohnZ]

Both the Assembly Manual and the Chassis Service Manual show the kickdown linkage adjustment procedure, which is pretty simple; follow it to the letter and your upshift/downshift points should be in the ball park, assuming you don't have internal problems in the transmission or vacuum leaks between the intake manifold and the modulator.

[lakeholme]

dab67,
John mentioning the Assembly Manual made me think...
The linkage adjustment procedure I'm talking about is called "Auto. Trans. -Trans. to Carb. Linkage Adjustment".  Remember my car is a 68, so I'm speaking from the 68 Assembly Manual.  In the 68 manual it is page 340 (handwritten), UPC M35 A17.  What I called the kickdown rod, the manual calls "throttle valve rod".  The procedure does look pretty simple: someone has to fully depress the accelerator pedal, while you adjust the swivel on the throttle valve rod.
Assuming neither one of us have the problems John mentions above --and since both cars seem to run fine otherwise, we probably don't-- this should be our fix.
As I recall, the mechanic who looked at my linkage did it by himself, so he may not have set it right.  John's advice about taking the manual to the shop is right!
Maybe this will help.  The weather is so lousy here.  It will probably be a couple of weeks before I can try it out.
Good luck to you, too!

[rich69rs]

In my experience, with my '69 RS 327-210 Hp/Powerglide, it is a combination of not only getting the kickdown adjusted properly, but also ensuring that the throttle linkage is adjusted properly.  The procedures in the assembly manuals are, obviously, for stock pieces and parts.  Aftermarket carbs, manifoldes, linkages, etc can have an affect on transmission operation, although, the general procedure for setting upshifts and downshifts would still be as described in the assembly manual.  Mine didn't work prpoerly either until I made sure that the carb linkage was adjusted properly (first) and then the kikcdown linkage -  but rmemember, my car is totally stock and the assembly manual info was spot on.  It is also worth mentioning that the transmission was totally rebuilt in 2004 as a part of the mechanical restoration process.

If I put my foot into it, the upshift from first to secont will occur between 55 and 60 mph.  If I am cruising at 55 or less ant put the pedal to the metal, the transmission downshifts to first.  Much above 55 mph, no downshift - you are above the speed where the transmission will downshift in order to prevent over-revving of the engine.

[dab67]

John and Rich:

Thanks again for the insight and direction. Rich you are correct regarding the downshifting at 70 or above I never looked at it it the sense at that speed, if it did downshift it probably blow the engine and tranny out!!!!! I never checked it at 55 or so. Once I get it out of the paint shop (new OEM SS Hood) I'll check it the downshifting at 55 or so. Like I stated this is my first "glide" and maybe I am overreacting to what I think should be and what it actually is. I will let you all know. And I do have both manuals John mentioned.

Thanks again Gentlemen!!!!!!!!!!!!!!!!!

[rich69rs]

The following link takes you to an "on-line" 1971 Chevrolet Transmission manual.  Powerglide is discussed in the first 23 pages.  It is a very good reference.

http://www.tocmp.com/manuals/trans/TTransChev1971/TTransChev1971.html

Quoting from pages 2, 13, and 14:

The transmission will automatically upshift to the high range or direct drive at between 10 and 68 mph depending on the particular vehicle and on throttle position.  When this shift occurs, the low band is released and the high clutch is applied which locks the planetary system causing it to  rotate as a unit


NOTE: The shift point speeds, shown for reference in this discussion, pertain to the Chevrolet 327 cubic inch V8 engine[/color]. Refer the chart for complete shift point listings.

Coast Downshift   As the vehicle slows down, governor pressure (holding the low-drive shift valve to the right) is reduced. At approximately 18 to 14 m.p.h[/color[/b]]., governor pressure is less than the opposing spring force of the shift valve springs

"Through-Detent" Forced Downshift   At all road speeds below approximately 70 to 62 m.p.h. the transmission can be automatically shifted to low range by depressing the accelerator linkage "throughdetent". This causes the production of maximum TV pressure and moves the detent valve to open TV   pressure to the detent passage. The resulting full TV pressure over-comes governor pressure acting on the shift valve. This action shifts the transmission to low gear as previously described. The transmission will remain in low gear until either the accelerator is released, or the car speed reaches the maximum upshift point (68-74 mph). At road speeds above approximately 63 m.p.h., governor pressure acting on the shift valve is high enough to prevent TV pressure from moving the shift valve. Therefore, regardless of accelerator position, the transmission will remain in high gear at all road speeds above approximately 70 m.p.h.

[dab67]

Awesome!!!!!!!!!!!!!!! Plain and Simply awesome!!!!!!!!!!!!!!!!!!!!

dab67

[lakeholme]

Rich,
Thanks for the web site.  I back tracked into the home page and found all kinds of interesting manuals and brochures.  First look, didn't see anything on 1st Gen Camaros.  Are there any other sites like that, which you know of?
Sorry, dab67, for getting this thread a little off topic...