C2/1967 Powerglide Burping. Possible Solution?

[Paul L.]

I posted on this subject here about two years ago and learned that in long-term storage conditions, a Powerglide will burp out fluid. That was the case again last winter during the storage period of six months. The quantity was three quarts. The fellows at the large commercial (450-car) storage facility where I leave my car are good-natured and have come to expect this behaviour from my 1967 but it does leave quite a mess for them to clean up.

I mentioned this elsewhere and a possible solution was brought to my attention (see link). But the in-line, one-way check valve is for early Powerglides 1955-61. Q. Would that valve work on my 1967?

http://www.classicchevy.com/product.asp?pf%5Fid=19%2D28&dept%5Fid=1849

[Joe R.]

Re: C2/1967 Powerglide Burping. Possible Solution?

Hi Paul:

I think there are two different "burping" problems associated with the Powerglide, and the solutions may also be different. I am not an expert on this topic, but based on what I have read, here is what I think the two problems are:

1) In early Powerglides the case was not vented and there was a "burping" problem that occurred at startup, when fluid could be pumped all the way up the dipstick tube and out the top. This occurred when the engine was started.

2) In later Powerglides this problem was fixed with a vent, I think. However, any Powerglide such as your 67 (and mine) can also leak fluid if it is parked for a long time. The normal fluid level in a Powerglide is below the point where the dipstick tube and the speedometer cable enter the case. The seals at those locations are not designed to be "under water," so to speak, so they can leak if fluid backs up behind them. When the car is parked for a few months, fluid can drain back out of the torque converter and raise the fluid level in the case to above where these seals are, leading to leaks.

I have read that the 67 Powerglide contains an internal check valve to prevent back flow out of the torque converter, but this valve is not always 100% effective.

Since my car is stored in my own garage during the winter, I prevent the problem by starting the car once a month to refill the torque converter. For your situation, you could consider draining the transmission pan after you park the car for the winter, although the amount the pan normally holds is less than the amount that could theoretically drain back out of the torque converter. This step might be enough to prevent the problem, though.

In summary, I think the device you referenced is targeted at a different problem that earlier Powerglides had. I do not know if it will have any effect on the problem you are experiencing. In order to help, it would have to be functionally in series with the internal check valve that is leaking. I don't know enough about the internal construction of the transmission to comment on whether that is the case.

[Paul L.]

Re: C2/1967 Powerglide Burping. Possible Solution?

Thanks Joe,
My burping is not through the fill tube so I guess the solution is not as illustrated. Too bad. I tell the fellows at the storage facility to leave the car be for six months. And they do. Perhaps the solution is to have them fire it up once a month and put it in Drive for several minutes.

[Joe R.]

Re: C2/1967 Powerglide Burping. Possible Solution?

Hi Paul:

I'm pretty sure that just starting the car once a month will do the job. I don't think you have to put it in Drive, but I'm not 100% certain. Maybe someone else who knows can comment.

I believe that simply starting the car gets the front pump in the Powerglide operating and re-fills the torque converter with the fluid that had drained out.

If you want to do a scientific test, shut the car off and check the fluid level using the dip stick to get a baseline level. Then, let the car sit for a month and check the fluid level again without starting the car. The level will likely read somewhat above the baseline level due to the torque converter draining down into the pan. Then, start the car, shut it off, and check the fluid level again. I suspect it will be right back at the baseline level.

[Mike M.]

Re: C2/1967 Powerglide Burping. Possible Solution?

i'd suspect that there are NO parts from a cast iron PG(c-1 vettes) that would interchange with or be adaptable to an aluminum PG as used in the c-2's. mike

[Terry R.]

Re: C2/1967 Powerglide Burping. Possible Solution?

Hi Paul I fixed my '62 with fresh o-rings on the dipstick tube and the speedo gear. Don't forget to put a little oil on the o-rings before you install.

[Paul L.]

Re: C2/1967 Powerglide Burping. Possible Solution?

Thanks Terry but the fluid does not come out the dipstick to my knowledge. As per Mike's comments it appears that the C1 and C2 transmissions are different. So other than starting the car once a month it appears that there is no solution unfortunately.

[Mike McKown]

Put a drip pan under it and forget about it.

Or get one of these cheap hand drill driven pumps with a tube and pump the transmission sump empty. In the Spring, dump it back in after you start the car.

I wouldn't start the car once a month unless you're going to drive it.

[Paul L.]

Re: Put a drip pan under it and forget about it.

A plastic pan from the Dollar Store is a good idea. That would save the storage fellows a lot of work.

[Terry R.]

Re: C2/1967 Powerglide Burping. Possible Solution?

Hi Paul I think Mike was refering to a cast iron P.G. 62 was the first year for aluminum and I believe 62,63 were very similar. A previous owner on mine had put two hardware fit all o-rings trying to get it to stop. I got the correct o-ring, lubed it up,slid it back in keeping it very straight and problem was solved till speedo gear housing started to leak. I'm a firm believer if it didn't leak in '67 it shouldn't leak in '07. Good luck