Powerglide Problems

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wsperdute
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Joined: Tue Jun 25, 2019 9:08 pm

Powerglide Problems

Post by wsperdute »

Hi, I am new to the site, but not to Corvairs, but I have a bit of a head scratcher. I have a 1962 900 Monza with an automatic powerglide transmission that only has DRIVE. I will give a little backstory, and a brief history of the lengths I have gone to remedy the situation. The engine is rebuilt as of 2016, the transmission and differential were purchased rebuilt 3 months ago from a reputable source. I installed the diff/ trans following the directions in the repair manual, and installed the engine the same as I’ve done at least twenty times before. I started the car, and as I gave it gas, it slowly crept forward. Later, I tried to push it and realized it was in gear. The car recognizes that the shifter is in NEUTRAL, so it starts, but once I give it some throttle it moves forward, in any gear. I have re-installed the cable as per the instructions (3/8” lower than the pan and all that stuff), when that didn’t work I took off the pan and made a visual confirmation that the shift cable was seated properly and adjusted the piston to just below flush with the second support web. I removed the engine to make SURE that the torque converter was seated properly. As of now I still have DRIVE and nothing else. If anyone out there has any suggestions I would greatly appreciate the help

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terribleted
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Re: Powerglide Problems

Post by terribleted »

Have you properly adjusted the TV lever?
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WinginEngineer
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Re: Powerglide Problems

Post by WinginEngineer »

I should probably keep my mouth shut since mine won't even go into gear at the moment, but we'll call this group brainstorming.

Two things come to mind.

1st, you said "just below flush with the second support web". Double check this picture and make sure it's the right web...
Screenshot_20190625-224155_Drive.jpg
2nd, i read a caution of similar symptoms when I rebuilt mine. Is your low band perhaps adjusted a bit snug?
Kevin - Phoenix/Mesa, AZ
1962 Corvair 700

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terribleted
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Re: Powerglide Problems

Post by terribleted »

Sounds like typical incorrect cable install or throttle valve adjustment or both. Follow the shop manual procedures to re-install the cable and if it is still funny properly adjust the Throttle Valve. Was the cable installed while connected to the dash selector and selector in drive per the manual?
Corvair guy since 1982. I have personally restored at least 20 Vairs, many of them restored ground up.
Currently working full time repairing Corvairs and restoring old cars.
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Located in Snellville, Georgia

wsperdute
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Joined: Tue Jun 25, 2019 9:08 pm

Re: Powerglide Problems

Post by wsperdute »

Hi, thanks for the ideas. First, wouldn't a too snug low band only affect the shift from DRIVE to LOW? Second, the cable was attached to the shifter and shifter was in DRIVE, I can see the slotted inner lever with the trans pan off and I can see that the ball end of the shifter cable is properly seated, so I assume that the cable is installed correctly. I can't seem to find any info on adjusting the Throttle Valve, could someone please post a link, or better yet dummy-proof instructions on how to adjust Throttle Valve?

WinginEngineer
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Re: Powerglide Problems

Post by WinginEngineer »

https://www.corvair.org/chapters/corvan ... anuals.php

1961 6E is the powerglide section. Shift cable adjustment or something along those lines. They call it a manual valve.

As far as the low band, think of it like a reverse drum brake, except the drum is the outside of the planetary gear. When you shift to low gear the fluid engages a piston that tightens the band around the drum, engaging the gear. If the band is too tight it would be the same net effect as having the piston engaged... in otherwords it will ALWAYS be in gear.

Low band adjustment is in the same manual :)
Kevin - Phoenix/Mesa, AZ
1962 Corvair 700

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terribleted
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Re: Powerglide Problems

Post by terribleted »

When installing the cable the bellcrank at the trans must also be rotated fully CCW as you insert the cable. It is pretty easy to screw this up. I have done it many many times and somehow now and then the cable just does not go in right causing starting in gear etc. (I am betting your valve needs adjusting) . Valve adjustment need a simple special tool (clark's sells one), and yes in the auto trans section of your 61 main book GM shop manual as noted above.
Corvair guy since 1982. I have personally restored at least 20 Vairs, many of them restored ground up.
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joelsplace
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Re: Powerglide Problems

Post by joelsplace »

Throttle valve and manual valve are two different things. Manual valve selects the gear (connected to shift cable) and throttle valve adjusts pressure connected to throttle rod).
114 Corvairs, 5 Ultravans and counting
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wsperdute
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Re: Powerglide Problems

Post by wsperdute »

Terribleted, first, thanks for taking the time to help me, second I am not sure what you mean by the "bellcrank". I have installed and re-installed the cable several times, and I can see the ball seated in the lever from below (the pan is off) when I shift the car at the dash, the piston moves inside the "tunnel" in the transmission.

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terribleted
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Re: Powerglide Problems

Post by terribleted »

The external throttle lever on the side of the trans is what I meant.

Sounds like the cable is in the lever ok , now take your special tool and adjust the manual valve, and follow with throttle valve linkage adjustment (throttle linkages under the car ) and if you are lucky it will fix your issue. The diagram above that Wingit posted is the adjustment you should do first.
Last edited by terribleted on Wed Jun 26, 2019 5:33 pm, edited 1 time in total.
Corvair guy since 1982. I have personally restored at least 20 Vairs, many of them restored ground up.
Currently working full time repairing Corvairs and restoring old cars.
https://www.facebook.com/tedsautorestoration/

Located in Snellville, Georgia

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terribleted
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Re: Powerglide Problems

Post by terribleted »

joelsplace wrote:
Wed Jun 26, 2019 1:45 pm
Throttle valve and manual valve are two different things. Manual valve selects the gear (connected to shift cable) and throttle valve adjusts pressure connected to throttle rod).
Yes actually looking just now at the 65 manual they call out the valve that the cable lever moves the manual valve , the throttle valve is positioned by the throttle linkages in the accelerator system and adjustment of the intermediate and engine throttle rods per the manual are used to properly position the TV valve.
Corvair guy since 1982. I have personally restored at least 20 Vairs, many of them restored ground up.
Currently working full time repairing Corvairs and restoring old cars.
https://www.facebook.com/tedsautorestoration/

Located in Snellville, Georgia

wsperdute
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Joined: Tue Jun 25, 2019 9:08 pm

Re: Powerglide Problems

Post by wsperdute »

First off, thanks to everyone for taking the time to try to help with my problem. Here's an update; I agree that the cable is inserted correctly, so I went on to step 2. I do not have the special tool, but I found a picture online of proper and improper adjustment of the manual valve. The description states that the piston should be just below flush with the second support web, and the picture verifies this position, so I adjusted the valve to sit "just below flush with the second support web". I have not adjusted the TV linkage under the car, because I cannot find a good description of how to adjust it. I did, however, shift the car into NEUTRAL at the lever, the manual valve changed position, but the wheels still don't spin (when the car is on ONE jackstand). Would the TV being out of adjustment cause the wheels to act like it is in gear?

WinginEngineer
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Re: Powerglide Problems

Post by WinginEngineer »

Wait, I thought you said it was ALWAYS in gear?
Kevin - Phoenix/Mesa, AZ
1962 Corvair 700

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terribleted
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Re: Powerglide Problems

Post by terribleted »

wsperdute wrote:
Fri Jun 28, 2019 10:28 am
First off, thanks to everyone for taking the time to try to help with my problem. Here's an update; I agree that the cable is inserted correctly, so I went on to step 2. I do not have the special tool, but I found a picture online of proper and improper adjustment of the manual valve. The description states that the piston should be just below flush with the second support web, and the picture verifies this position, so I adjusted the valve to sit "just below flush with the second support web". I have not adjusted the TV linkage under the car, because I cannot find a good description of how to adjust it. I did, however, shift the car into NEUTRAL at the lever, the manual valve changed position, but the wheels still don't spin (when the car is on ONE jackstand). Would the TV being out of adjustment cause the wheels to act like it is in gear?
The throttle adjustment procedures are in the 61 Corvair shop manual on page 9-3. The last step says adjust swivel O this should be swivel D. This adjustment is almost certainly not your problem but is essential for proper upshifting. I feel you have an internal trans issue. refer to the powerglide trouble charts at the end of the automatic trans section in the 1961 Chassis shop manual for clues.
Corvair guy since 1982. I have personally restored at least 20 Vairs, many of them restored ground up.
Currently working full time repairing Corvairs and restoring old cars.
https://www.facebook.com/tedsautorestoration/

Located in Snellville, Georgia

joelsplace
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Re: Powerglide Problems

Post by joelsplace »

He did start out saying all he had was DRIVE so everyone's answers were dealing with that symptom.
114 Corvairs, 5 Ultravans and counting
Northlake, TX

wsperdute
Posts: 10
Joined: Tue Jun 25, 2019 9:08 pm

Re: Powerglide Problems

Post by wsperdute »

Hello again everybody, sorry for the confusion. The shift lever moves freely between gears, and the NEUTRAL safety switch is operational, as it only starts with the lever in NEUTRAL. The TRANSMISSION is always in gear (DRIVE or LOW not really sure). Terribleted, I will look at the troubleshooting section again, but if I remember correctly the 2 options listed were "shifter cable improperly installed and low band out of adjustment". Thanks again, everyone, for taking the time to help.

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