I have a powerglide out of a '63 Impala in my '51 Fleetline that has performed flawlessly for about 4 years , until night before last , I was going down the road , about 40 mph , and for a split second , it seemed to "kick back" into p***ing gear , I have never had this happen , so I immediately took my foot off of the accelerator , I started down a small road at about 10-15 mph and pulled into by buddys house , when I got ready to leave , I was driving out the road , and the car wouldn't come out of low gear , I thought I was shifted into low gear by accident , but I was in "drive" , the car would never shift , and it wasn't like there was any slippage like the ****** was going out , it was like I had shifted the car to low gear and it wasn't shifting , no free-wheeling after you let off of the accelerator , anybody have any suggestions?
Check the vac*** to the modulater,kick down linkage,fluid level and condition may have a shift valve stuck.
Check the shift linkage first. Make sure kickdown linkage isn't stuck. That should be a rear pump trans, the priming valve could be stuck or the drive pin sheared. Governor could be stuck. Low drive valve could be stuck. Since it happened driving down the road, the drive pin on the rear pump gear sounds like a likely suspect. The modulator valve being inop would cause a harsh upshift.... used to pull the hose on them to make them shift harder.
Powerglides get varnished up easily (burnt fluid); what does the fluid look/smell like? That contributes to gumming things up, especially the valving. Drop the pan, see what's in the bottom (some metallic looking material is OK due to wear, a lot is't good), and check the internal linkage. The "rooster comb" on Powerglides is known to bend or break, that causes it to not engage the manual valve right. Filter plugged? Butch/56sedandelivery.
Pull the vacuum line, to the trans, off the motor and **** on the line. If there is no resistance either the short rubber hoses are cracked or the modulator is broken. Easy check to do before tearing into the trans.
When we used to use these transmissions because that was what we had the two main problems that they ever had was va***m modulater and band adjustment. badn adjustment does not happen abruptly as a rule but a vacuum modulater could bust a diaphragm or spring in an instant. Tell you a story, I bought a '64 Malibu SS once cheap because the transmission didn't work. I brought a modulator with me and a couple of quarts of transmission fluid. The fluid was low so I topped it off and then the car would roll under its own power but it didn't shift, so I rolled under it and switched out the modulator, and drove it home.
Thought modulators were to control the harsh upshifts and downshifts. You can put a modulator in and give it a try. After that the TV rod (some call it a kickdown) would be where I would start, then governor, then direct drive clutch and it's seals. The band is used for Lo gear, so the only way it would stay in Lo from a band is if the release port of the band servo is clogged.
Well, guys , I found the problem , and if I hadn't seen it for myself , I wouldn't have believed it , my transmission was 1 quart low , that was it , I would've thought that, if anything , it would've slipped , not just hung in low gear , in any event , thanks for all the suggestions , but , a quart of ****** fluid does wonders....
Obvious is a word we seem to ignore, LOL! However, I would still check the modulator for it pulling trans fluid into engine. These things go bad and start eating fluid.
If it's that sensitive to being low on fluid,the filter may have fallen off and is laying in the pan....It happens a lot and a lot of cars got parked because of it.....
Power slips are that sensative believe it or not. If the filter were lieing in the pan adding a quart would not cure it. Over filling it would be what it takes to cure it.
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