2 Speed power-glide odd shifting.

[Gmtruckguy92]

Hey guys, have a 67 c10 with a freshly rebuilt 327 and it also has the 2 speed power glide tranny, the trans wasn't messed with when the motor was rebuilt.

I started noticing that while driving right before it shifts it acts as if its in neutral and the rpms go up then it seems to catch the gear and shift. Wasn't positive if it was due to the kick-down not being attached on the carb and perhaps its stuck or what the problem could be?

any advice would help!

[turp mcspray]

I had a 65 impala when I was a kid. The glide did the same exact thing for awhile, then completely died. Sounds like a good reason to swap in a th350. You'll be glad you did!

[Gmtruckguy92]

Originally Posted by turp mcspray

I had a 65 impala when I was a kid. The glide did the same exact thing for awhile, then completely died. Sounds like a good reason to swap in a th350. You'll be glad you did!

oh boy, i had a feeling it was going out......we got an extra trans with the truck but idk what kind it is, i guess ill have to get all the markings and numbers off it tomorrow.......but again idk the condition of that trans either.....

[mmiddle]

Slip-and-slide Power glide!
The kick down cable would not cause this. It sounds like a pressure problem. Ether the fluid is low or dirty or something is failing inside. Does a PG have a modulator? if so it could be the modulator maladjusted or failing. The modulator controls the line pressure.

[Gmtruckguy92]

Originally Posted by mmiddle

Slip-and-slide Power glide!
The kick down cable would not cause this. It sounds like a pressure problem. Ether the fluid is low or dirty or something is failing inside. Does a PG have a modulator? if so it could be the modulator maladjusted or failing. The modulator controls the line pressure.

I'll check the fluid tomorrow, since i need to check to P/s fluid bc its making a slight noise. As far as the modulator i have no earthly idea!

[PanelDeland]

If you have to replace the tranny,there's no reason to go halfway.Go ahead and upgrade to an OD.

[71K20chevy]

I don't believe Glides have modulators. (Edit-looks like earlier powerglides with cast iron case did indeed have a modulator.)

Run er till she blows!

[mmiddle]

Ya, Im not sure. I don't have any direct experience with them. I know they are great for drag racing....

[Gmtruckguy92]

Originally Posted by PanelDeland

If you have to replace the tranny,there's no reason to go halfway.Go ahead and upgrade to an OD.

well without knowing what trans i got with the truck i cant make decisions, whether its got od or not its gonna be cheaper rebuilding it then finding a reasonably priced good one

Originally Posted by 71K20chevy

I don't believe Glides have modulators. (Edit-looks like earlier powerglides with cast iron case did indeed have a modulator.)

Run er till she blows!

How would i find that out?

Originally Posted by mmiddle

Ya, Im not sure. I don't have any direct experience with them. I know they are great for drag racing....

Strange that it would be bolted to a low hp sbc

[71K20chevy]

Stick a magnet up to the case! (Not the pan)

If it sticks, you got a cast tranny.


But I agree with the OD suggestion above, however...

[bobs409]

I've had a couple powerglides do this. None of them died on my watch however.

The one car was a 68 Impala and the previous owner had it at transmission shop. They couldn't figure it out! ?? I put 38,000 hard teen age miles on it after that and it was still going strong when I sold it.

It was annoying, I would just leave off the gas a bit while it was shifting to avoid the rev.

My 66 Impala will occasionally do this too but not as bad.

[NC67Chev]

I'm hoping for you that it's just a fluid level issue. A year or so ago, I was fighting some significant leaks on my powerglide. Anyway, a couple of times I went to drive it and it would behave as you describe. I checked the fluid, which was a little low....added fluid and problem was solved.

I'm not claiming that you have a leak, but I'm assuming the radiator was pulled when the motor was taken out....meaning the transmission cooler lines were disconnected.

Unless someone put in a PG from an older model, you should have an aluminum version.

Also, the aluminum PG's do have a vacuum modulator. It's located on the drivers side at the rear of the transmission.
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[Gmtruckguy92]

Originally Posted by NC67Chev

I'm hoping for you that it's just a fluid level issue. A year or so ago, I was fighting some significant leaks on my powerglide. Anyway, a couple of times I went to drive it and it would behave as you describe. I checked the fluid, which was a little low....added fluid and problem was solved.

I'm not claiming that you have a leak, but I'm assuming the radiator was pulled when the motor was taken out....meaning the transmission cooler lines were disconnected.

Unless someone put in a PG from an older model, you should have an aluminum version.

Also, the aluminum PG's do have a vacuum modulator. It's located on the drivers side at the rear of the transmission.
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well i checked the fluid it was a little low so i added some then drove it and its still doing the same thing......






got some pics of the extra trans we received when we got the truck, i believe its a 700-r4/4l60e

[motorcritter]

Looks like you got a 'free' 700R4. Check it out, overhaul it, and run it. The PG problems you're experiencing are the same ones my '62 Chevy Biscayne did before the transmission didn't 'transmit' anymore. I never got a chance to fix it- parked it in front of my then-girlfriend's house (where it died) went out of town for a weekend (in her car) and a drunk neighbor hit it and totaled it- and her Lincoln, too. You'll like having OD, and there's plenty of info here on the board, and elsewhere.
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[Gmtruckguy92]

Originally Posted by motorcritter

Looks like you got a 'free' 700R4. Check it out, overhaul it, and run it. The PG problems you're experiencing are the same ones my '62 Chevy Biscayne did before the transmission didn't 'transmit' anymore. I never got a chance to fix it- parked it in front of my then-girlfriend's house (where it died) went out of town for a weekend (in her car) and a drunk neighbor hit it and totaled it- and her Lincoln, too. You'll like having OD, and there's plenty of info here on the board, and elsewhere.
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what all would i do the "check it out" ive never messed with transmissions so i dont know anything about them

[motorcritter]

Without opening it up completely, pulling the pan and looking for excessive debris and noting the fluid condition (clear red, murky brown, 'burnt' smell, just plain old ATF odor) can tell a lot about it. To be sure, drop it off at a reliable transmission shop (someone recommended by a close friend) and get it rebuilt- it won't cost as much as a new reman unit, and you know exactly what you've got. Those transmissions are pretty solid, but not without their weaknesses. A good rebuild can eliminate those shortcomings, and you'll have an overdrive transmission that is totally worth the effort and head and shoulders above a Powerglide- especially one that appears to be on its way out.
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[luvbowties]

Originally Posted by Gmtruckguy92

what all would i do the "check it out" ive never messed with transmissions so i dont know anything about them

Hi, Gmtruckguy, got good news for you...and NOT trying to start an argument. If it had no signs of this before engine work, you may be in luck. They probably just left the vacuum line loose from the modulator. This can be in 1 of 2 places. A short neoprene hose near the carb hooks a vacuum source onto a steel tube that goes down to tranny--it should be hooked up. On the lower end of steel tube, there is another short neop. hose that connects tube to modulator--make sure it is hooked up.

If both hoses are connected, start engine with neop. hose loose at modulator. It should have good vacuum; if not, the upper hose OR the tube is not holding vacuum. Find leak and repair.

Also possible, but less likely: If the kickdown linkage happened to get hooked into wrong hole in carb linkage, or maybe not hooked up at all, it COULD very well cause this so-called "overrunning" condition.

Even least likely would be the linkage needs adjusting; but the engine repairmen would not likely 'screw' the linkage out of adjustment. Yet, linkage improperly adjusted could also cause this same condition. DO NOT TRY ADJUSTING EXCEPT AS A LAST RESORT--EVEN THEN, HAVE IT DONE BY A TRANS PRO. He'd probably charge only a few bucks--I've done all these repairs for free in the past, but was not mechanic'ing for a living at the time.
Sam

[Gmtruckguy92]

Originally Posted by luvbowties

Hi, Gmtruckguy, got good news for you...and NOT trying to start an argument. If it had no signs of this before engine work, you may be in luck. They probably just left the vacuum line loose from the modulator. This can be in 1 of 2 places. A short neoprene hose near the carb hooks a vacuum source onto a steel tube that goes down to tranny--it should be hooked up. On the lower end of steel tube, there is another short neop. hose that connects tube to modulator--make sure it is hooked up.

If both hoses are connected, start engine with neop. hose loose at modulator. It should have good vacuum; if not, the upper hose OR the tube is not holding vacuum. Find leak and repair.

Also possible, but less likely: If the kickdown linkage happened to get hooked into wrong hole in carb linkage, or maybe not hooked up at all, it COULD very well cause this so-called "overrunning" condition.

Even least likely would be the linkage needs adjusting; but the engine repairmen would not likely 'screw' the linkage out of adjustment. Yet, linkage improperly adjusted could also cause this same condition. DO NOT TRY ADJUSTING EXCEPT AS A LAST RESORT--EVEN THEN, HAVE IT DONE BY A TRANS PRO. He'd probably charge only a few bucks--I've done all these repairs for free in the past, but was not mechanic'ing for a living at the time.
Sam

this tube? Red line, also where does the black lined hose connect? its connected to the back of the carb but idk where else it connects?


feels like the hose isnt straight on but its on. When we put it together we werent sure/couldnt remember which bolt on the trans the tube and trans dipstick mounted to. tried both bolts for the tube and neither would give it an easy slide on connection.....

[Gmtruckguy92]

well its all connected and whatnot....

[71K20chevy]

Red line, vacuum modulator for tranny. You won't need this line for the 700R4.

Black line, looks like a plugged off vacuum hose for something else. Also looks like it could be eliminated.

If you do remove them, be sure to plug the holes!

[425HP409]

Originally Posted by Gmtruckguy92

Hey guys, have a 67 c10 with a freshly rebuilt 327 and it also has the 2 speed power glide tranny, the trans wasn't messed with when the motor was rebuilt.

I started noticing that while driving right before it shifts it acts as if its in neutral and the rpms go up then it seems to catch the gear and shift. Wasn't positive if it was due to the kick-down not being attached on the carb and perhaps its stuck or what the problem could be?

any advice would help!

I believe that you answered your question with your comment "Wasn't sure if it was due to the kick-down not being attached on the carb".... The "Kick-down" also has pressure control for the transmission upshifts. If it is not connected to the carburetor and adjusted properly you can have the exact symptom you are describing, and it will lead to transmission failure if not corrected. With it not connected and you accelerate, the transmission is not getting the pressure increased from the "Kickdown" linkage, and thinks that the throttle is at idle and will have low pressure, resulting in soft application of the clutches, and a "neutral" sensation and soft high gear engagement, which is detrimental to the clutches. If you reconnect the linkage to the transmission, make sure that the vacuum modulator has manifold vacuum to it, the transmission should operate just like it did before the engine was rebuilt. My 68 came with a Powerglide and it never had any problems while being used as a farm truck and hauling trailers filled with livestock. It is a very strong and durable transmission. Good Luck, and remember, it is Kickdown and Throttle Pressure linkage......
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[Gmtruckguy92]

We reattached the kickdown and i drove it today and its still showing symptoms......am i to late?

[Gmtruckguy92]

wrong thread