'54 PowerGlide Speedo Gear

[Jim L.]

I can't be the only one who has ever run into this problem. I just can't be. However, I may be the only one who hasn't figured out a solution. So, help me, here, folks.

The main problem is that the speedometer gear on my '54 leaks transmission fluid. The leak is around the shaft itself. I've been under the car with the engine running and the cable disconnected and have seen this with my own eyes. It leaks a lot of fluid.....too much to drive the car.

What I can not figure out is why it leaks or, after looking at how the speedometer gear housing is made, why other '54s (and '53s) don't leak.

Now before you start to respond, know this: The speedo gear on the '53 and '54 PowerGlides is different from all the later gears and housings. The gear, the shaft, and the housing are an assembly and it's not made to come apart (or at least I haven't found a non-destructive way to disassemble it).

You can see some examples in the attached photo. You can also see an NOS truck speedometer gear I bought just so I could analyze these things. The one property that NOS gear has that is absent from the three '54 gears in the picture is that there feels like there is some kind of seal on the shaft; it requires a little effort to turn. In contrast, the '54 gears turn with complete freedom.

So...... How are these things supposed to seal against leaks? And what can I do (short of just sticking a cork in the side of the transmission), to stop the leak in my '54?

Thanks in advance,

Jim

PS yes, the two plastic gears are chewed up and there is a steel gear pictured. That's a topic for another thread.

[Michael L.]

Re: '54 PowerGlide Speedo Gear

Jim, the person who rebuilt my '55 Powerglide left out an "O" ring that seals the shaft for the speedo gear. A reliable trans shop familiar with cast iron 'glides fixed mine in a day. The other builder also failed to seal the dip stick tube and the rear main seal was also junk... My glide leaked like a sieve, it is no dry as a bone.

Mike

[Troy P.]

Re: '54 PowerGlide Speedo Gear

I believe there is an O ring that goes between the threads and the hex nut part of the gear shaft. If so that would seal inside the trans case.

[Jim L.]

Re: '54 PowerGlide Speedo Gear

Michael and Troy, thanks for taking the time to respond.

Michael, as far as I've been able to determine, your 55 PowerGlide uses the later style of housing and plastic gear/shaft, as depicted in the two photos below. While there might very well be an o-ring sealing the '55 shaft, it has been, to date, beyond me to figure out whether there is an internal O-ring in my '54 speedo gear or not since the assembly wasn't intended to ever be taken apart.

Troy, as I read your description, I think you are describing the housing and locating an o-ring or gasket between the hex of the housing and the body of the transmission case, aren't you? That does seem like a good idea, but that's not where I'm seeing fluid come out. I'm seeing it come out from within the bore of the housing. Or are you suggesting that I jam an O-ring in there somehow?

Jim

[Troy P.]

Re: '54 PowerGlide Speedo Gear

Yes, I was suggesting an O ring on the outside of the gear caseing to seal against the trans housing. Have no idea what to do about a leak through the center of the gear case.

Roy Braatz is the expert on powerglides. Hopefully he'll see this and respond. Or contact him directly.

[Roy B.]

Re: '54 PowerGlide Speedo Gear

The Speedo gear housing uses no seal ,the Speedo cable (not the cable housing) had a little o ring to keep oil from running up the cable some times at both ends to keep oil out of the speedometer or tack .
Sounds like to me your PG top AIR VENT is clogged up not letting the air pressure out so it goes out the speed gear area. The built up turbulence (air pressure ) has to get out some where.

[Jim L.]

Re: '54 PowerGlide Speedo Gear

Roy,

Thanks for taking the time to write. Your experience is appreciated. I'm as dumb as a brick when it comes to PowerGlides.

I'll look for evidence of the o-ring on the cable. If it's no longer there , I need to know more about it. Does it simply slip over the end of the cable? Does it need to have a particular outside diameter?

Where is the air vent you mention? As grimy as my car is (it's unrestored), I'd bet money the vent is dirty and in need of cleaning.

Thanks for your help.

Jim

[Roy B.]

Re: '54 PowerGlide Speedo Gear

Roy,

Thanks for taking the time to write. Your experience is appreciated. I'm as dumb as a brick when it comes to PowerGlides.

I'll look for evidence of the o-ring on the cable. If it's no longer there , I need to know more about it. Does it simply slip over the end of the cable? Does it need to have a particular outside diameter?

Where is the air vent you mention? As grimy as my car is (it's unrestored), I'd bet money the vent is dirty and in need of cleaning.

Thanks for your help.

Jim

It's a small o ring that just fits over the cable to seal the cable to the inner gear as you tighten the cap against the gear housing.Some cables have it as a little washer that does the same thing.
The vent cap is on top of the PG center housing , the PG inside is like a hurricane the pressure needs to get out some where

[Jim L.]

Re: '54 PowerGlide Speedo Gear

The vent cap is on top of the PG center housing , the PG inside is like a hurricane the pressure needs to get out some where

Roy, I'm not finding the vent.

If you would take a look at the photo below, maybe you could tell me what I'm doing wrong. Is the vent item #1 in the picture, or #2, or #3 or #4 or something completely different? #2, #3, and #4 in the picture all appear to be hex-head pipe plugs.

For what it's worth, the transmission in my '54 does not have plug #3. The boss is there, but it's never been drilled and tapped.

Thanks,

Jim

[Roy B.]

Re: '54 PowerGlide Speedo Gear



Sorry was thinking of a later PG, (see 58 pic) but the inner gear of the Speedo housing has a snake type cutting to hold back any oil ( you can see that on plastic driven gears ) your's inner driven gear (shaft) must be worn and not doing the job holding back the oil.