Team Chevelle banner
  • Hey everyone! Enter your ride HERE to be a part JUNE's Ride of the Month Challenge!

Status
Not open for further replies.
1 - 11 of 11 Posts

·
Registered
Joined
·
37 Posts
Discussion Starter · #1 ·
I have a '66 SS. 396, 360HP, 2 speed powerglide. I am not certain of the rear end ratio (probably whatever was stock).
It shifts at approx 23 mph. This seems very soon. When should it shift? A friend said to adjust the modulator. I have attempted to do so, but have been unable to. Maybe I am trying wrong. Is this correct advice? Could the problem be that the modulator is malfunctioning all together and needs replacement? Where should I go from here?

Thanks,

gerald
 

·
Registered
Joined
·
119 Posts
Make sure you have the rod from the carb to the transmission hooked up and adjusted right. This will greatly effect the shift points on a powerglide.
 

·
Registered
Joined
·
148 Posts
Hey Gerald,
Mike is right; it needs more throttle pressure. Try increasing the tension on your kick down rod, but do it a little at a time. Also make sure your vac mod is good. mgg (Gold # 209)
 

·
Registered
Joined
·
23 Posts
I'm not too sure about powerglides, but TH350/400's usually don't have stock adjustable modulators. Aftermarket ones are though. Not too expensive.

Ian


------------------
Member #232
66 Malibu, 454, Th400
Gatineau, Quebec
 

·
Registered
Joined
·
37 Posts
Discussion Starter · #5 ·
Mike S. & Manny G:

Now I know what that linkage is that is behind the carb and goes down near the transmission-- The one that is hooked up to NOTHING on either end!
This car does not have the original Holley carb, It has a Carter.

What should I do now?

Thanks

gerald
 

·
Registered
Joined
·
37 Posts
Discussion Starter · #6 ·
Mike S. & Manny G:

Now I know what that linkage is that is behind the carb and goes down near the transmission-- The one that is hooked up to NOTHING on either end!
This car does not have the original Holley carb, It has a Carter.

What should I do now?

Thanks

gerald
 

·
Registered
Joined
·
37 Posts
Discussion Starter · #7 ·
Mike S. & Manny G:

Now I know what that linkage is that is behind the carb and goes down near the transmission-- The one that is hooked up to NOTHING on either end!
This car does not have the original Holley carb, It has a Carter.

What should I do now?

Thanks

gerald
 

·
Registered
Joined
·
148 Posts
Hey Gerald,

That's your Kick down linkage; either hook it up to the kick down lever on the trans or put a slight amount of pressure on the kick down and tie it off. That will increase the throttle presure and raise the shift speed. It won't however give you kick down capabilities. The make of carb shouldn't matter. All the trans wants is some pressure on the lever so it knowns when you need it to drop down to low. mgg
 

·
Registered
Joined
·
37 Posts
Discussion Starter · #9 ·
The top end of the rod does not reach up to the throttle linkage. Is there a piece missing? The bottom end of the rod has a hole in the side of it which goes over a fitting on a lever on the side of the transmission--but it doesn't fit on very snug. What do I need (besides the know how) in order to remedy this problem?

Thanks,

gerald
 

·
Registered
Joined
·
3,001 Posts
My PG was shifting funny after have it rebuilt, it would downshift when slowing down and quick upshift to high gear at low speeds. I went back to the shop that did the work, I've know this man for years and he told me that Powerglides are real sensative to the vaccum source. We switched mine around to the manifold and it made all the difference, shifting was normal. He explained this can be caused by not having the original carb, or the carb being dirty etc. I had a remanufactured one on my 283, looked identical to the original but the carb numbers were not the same.

Try a different vaccum source, like from the intake, the carb port may not have enough vaccum to let the tranny shift right.

[This message has been edited by elcamino (edited 07-05-99).]
 

·
Premium Member
Joined
·
8,074 Posts
Gerald, the default axle ratio for your '66 L34/M35 combo was 3.31:1. It remained default for '67, but from the factory they expanded the optional ratios for '67 to include 3.07 - 4.10 as options with that drivetrain. According to my '67 manual, your combo should upshift at 13.9 to 17.1 mph with a closed throttle or 70.7 to 78.5 mph full throttle. This is with the stock for '67 F70-14 tires. When I checked the specs on my L22/M35 I found mine to be operating bang-on (approx. 17 mph closed or 51 mph full). Powerglides... Hey, they're light & simple.
 
1 - 11 of 11 Posts
Status
Not open for further replies.
Top