Of Speedometers and Transmission Vents...

[stumps]

During the first few miles of my deuce's recovery, the speedometer was working nicely.... Suddenly it whipped around past 60 and spent the rest of the 1200 miles bouncing off of the back side of the zero peg. The odometer continued to work just fine.

I noticed a brown liquid plastic like substance on the inside bottom edge of the dial glass...rust maybe? Hmmm??? I decided to investigate when I got home.

Well, I can't live without a speedometer, so I popped the speedometer out of the dash, and it quickly became apparent that the brown liquid plastic like substance was GL5 transmission oil. My speedometer was partly full of transmission oil! Oh Joy!

If the transmission vent is plugged, and the transmission is full up with oil, the waterproof nature of the deuce's systems can come back to bite you. The pressure that builds when the transmission gets warm has to go somewhere, and in my case, up the waterproof speedometer cable, and into the speedometer was the place to go!

The repair for this problem is to make a little pry bar out of a screwdriver, and carefully pry open the back of the bezel ring that seals the dial glass to the case. Then you have to liberally flush all of the GL5 out of the speedometer mechanism.

I haven't yet decided what to do about lubricating the speedometer bearings. The odometer tap off gear obviously should get a little lubriplate, but I don't know about the fine needle bearings in the eddy brake mechanism. I'll get back to you on that when I figure out the best course of action.

Keep those transmission vents unplugged!

-Chuck

 

[jasonjc]

The speedometer hooks up to the T-case an adapter that is greased. Not shure grear oil can make it up thought that? But I had a truck with a speedometer full of eng oil. I have no idea how it got there. Did as you said open it up and cleaned it out. But I used carb cleaner. Not the thing to use took the number off the face

 

[stumps]

The speedometer hooks up to the T-case an adapter that is greased. Not shure grear oil can make it up thought that? But I had a truck with a speedometer full of eng oil. I have no idea how it got there. Did as you said open it up and cleaned it out. But I used carb cleaner. Not the thing to use took the number off the face

Trust me, it can. This is good old stinky GL5 gear oil. My hands still stink of it!

In the future, use VM&P Naptha, which is the same as Ronsin Lighter fluid. It won't harm plastics, or paint, but does a great job of moving the heavy oil.

-Chuck

 

[dittle]

And thats when Stumps said "Hey, there's brown stuff flying all over the inside of the cab". His buddy replied "Check your shorts". Ok, maybe not so funny in text type.

 

[stumps]

And thats when Stumps said "Hey, there's brown stuff flying all over the inside of the cab". His buddy replied "Check your shorts". Ok, maybe not so funny in text type.

If I was ever in a deuce that honestly ran the speedometer past 60MPH, and started banging the needle against the 0MPH stop, there *would* be brown stuff flying around in the cab.

-Chuck

 

[stumps]

Ok, I just reinstalled my newly cleaned speedometer. In order to make certain that it doesn't get filled up with transmission oil again, I pulled the sheet metal hump that covers the transmission, and removed the transmission vent. As I suspected, it was stuck closed. I took the back end of a drill bit, and pressed fairly hardly to unstick the rubber washer, and put some lubricant on the washer in hope that it won't stick again anytime soon.

Moral of the story, if you don't want your speedometer filled with transmission oil, make sure your transmission's vent is clear and working properly.

-Chuck

 

[cranetruck]

A couple of things, the speedometer cable comes from the adapter on the transfer case, not the transmission and the breather on the transmission is important, but there may a leak around the shift lever to consider also. If you prepare for fording, the shift lever boot must be tight or the transmission will not maintain air pressure (it isn't much to begin with, since the vent will release the pressure at less than 1 psi).

I have an adapter on my desk here and it is not possible to blow air through it, not by mouth anyway.
Your point is well taken, but there may be another problem.

 

[stumps]

A couple of things, the speedometer cable comes from the adapter on the transfer case, not the transmission and the breather on the transmission is important, but there may a leak around the shift lever to consider also. If you prepare for fording, the shift lever boot must be tight or the transmission will not maintain air pressure (it isn't much to begin with, since the vent will release the pressure at less than 1 psi).

I have an adapter on my desk here and it is not possible to blow air through it, not by mouth anyway.
Your point is well taken, but there may be another problem.

I figured out that the speedo cable had to connect to the transfer case shortly after I posted my note.... but alas I was on the road and couldn't correct it until now.

The vent on my transmission was hard stuck closed. It took 5-10 lbs of push with the shank of a drill bit to unstick its washer from the seat. That would have translated into way more than 1psi I am pretty sure... probably something like 50psi.

I will check the T-case vent next.

The SAE 85/90 gear oil appeared in the speedometer case while my buddy was driving. I doubt it was just lingering in the cable sheath. It had to take quite a bit of pressure to push the oil through the speedometer's cable bearing. The oil appeared about 20-30 miles after we started driving.

Also, try puffing as hard as you can on a pressure gauge. You won't be able to achieve even 1/2 psi that way.

-Chuck

 

[stumps]

The speedometer hooks up to the T-case an adapter that is greased. Not shure grear oil can make it up thought that? But I had a truck with a speedometer full of eng oil. I have no idea how it got there. Did as you said open it up and cleaned it out. But I used carb cleaner. Not the thing to use took the number off the face

Hi Jason. You are right, the transmission can't pressurize enough to push oil out the transfer case.... something about it being a divorced transfer case.... but the transfer case can pressurize enough to push oil out of its adapter and into the speedo cable... remember, it had to push the oil through the bearing in the end of the speedometer to get into the case at all.

I'll check my T-case's vent tomorrow. If it is stuck as hard as my transmissions was, it could easily allow enough pressure to blow oil down the cable. And there was a fair bit of spittering and spattering of oil around the area of the T-case.

-Chuck

 

[Warthog]

No need to worry about your Speedometer. They are all Radioactive and will be recalled shortly.....

 

[gringeltaube]

...................

I'll check my T-case's vent tomorrow. If it is stuck as hard as my transmissions was, it could easily allow enough pressure to blow oil down the cable. And there was a fair bit of spittering and spattering of oil around the area of the T-case.

You might also have to check/replace the small seal in your speedo adapter...
See details here http://www.steelsoldiers.com/deuce/29471-speedo-cable-leaking.html and here http://www.steelsoldiers.com/deuce/36012-speedometer-adapter-leaking-gear-oil.html

G.

 

[stumps]

No need to worry about your Speedometer. They are all Radioactive and will be recalled shortly.....

Actually, no, mine isn't.... I checked it, and all of my other gauges. I have more than a little trouble understanding why they would make deuce gauges glow in the dark, but maybe they did?

Tritium glows at 1/2 brightness after 15 years. 1/4 brightness after 30 years. I have a few tritium dialed watches from the '70s and they don't glow at all anymore.

-Chuck

 

[airmech3839]

I am having same problem....my speedo finally stopped working and my Transfer case seals are now leaking big time....I cleaned my vent the other day and it helped for about 10 miles then speedo did its thing of pegging out....I drive it everyday and was gonna replace the vents....did not realize they could stick that bad....will pull it back off and try that ..... My speedo adapter is wet and outer hose of speedo is wet as well... maybe time for new speedo adapter and hose as well as seals on transfer case!!!

 

[stumps]

I am having same problem....my speedo finally stopped working and my Transfer case seals are now leaking big time....I cleaned my vent the other day and it helped for about 10 miles then speedo did its thing of pegging out....I drive it everyday and was gonna replace the vents....did not realize they could stick that bad....will pull it back off and try that ..... My speedo adapter is wet and outer hose of speedo is wet as well... maybe time for new speedo adapter and hose as well as seals on transfer case!!!

You have to really be sure the vent is clear. On mine, I had to take the back end of a drill bit and press about 10lbs to get it to break free. Then I sprayed it full of a lubricating oil in hopes that it won't stick again.

You might want to just punt and replace the vents with a hose barbs, and plumb them all by rubber hose up to the vehicle's air cleaner. It is vitally important that the various gear cases not pressurize!

-Chuck