The Stovebolt Site Forums The Shop Area Driveline How do I check the level of the transmission fluid?

How do I check transmission fluid level in a 1949 chevy 3100 216 3 on the tree? I may have over filled it today.

There should be a filler plug on the passenger side of the transmission.

Fill to level if warm, fill about 1/2" below level if cold.

Through what hole in the transmission did you fill (overfill) it?

A little overfull is not dangerous.

Top view of Cross section 3 speed Transmission Group # 8.971 Filler Plug (Top of picture)

I took out the filler plug on passengers side while cold and thought I should fill till it started to drain out. It never drained. What concerns me is I put in about 1.5 quarts. 1 quart more than it calls for. Any bad reason why it never over flowed if it only takes 1.5 pints? I drove the truck today without any issues. The reason I filled it is because I get a stain in the garage about the size of a 50 cent piece every time after parking. Been since 8/2011 so I thought it time to top it off.

If an A-D is not dripping under the u-joint enclosure, you are out of lubricant.

Where did you find the 0.5 qt recommendation.? That is how much you should add if you open and then close the u-joint housing.

The-u-joint housing gets it lubricant from the gear oil moving back into the u-joint housing from the transmission.

That drip is hard to eliminate. Two of my trucks now have no drips under the u-joint housing. I expect that will not last long.

Place a disposable diaper on the floor under the u-joint housing.

In the 3 speed tranny section of the truck manual for these trucks it says add 1.5 pints of oil after installation. Am I miss reading this? I thought that was low. Is this only if the u-joint housing was removed and not the tranny?

Sounds right. But, still check the level after driving the truck for a short trip. That .5 pints might not include the .5 pints needed for the inclosed u-joint?

OK, that's the directions I used. What is the right way to check the level after that short trip? Do I remove the filler plug and if it doesn't flow out I am good?

If you did not remove U-joint ball housing.
Fill to level of plug hole if warm, fill about 1/2" below level if cold.

When the U-joint ball housing is removed and reinstalled.
1948 - 1951 Chevrolet Truck Shop Manual Read Number (5) Under Assembly
Your suppose to fill the ball housing through the speedometer drive gear.
It does not indicate how much fluid.
GM tells you to do this so the U-joint and the torque tube bushings have some
lubrication until the tranny starts funneling fluid into the U-joint ball housing.

Here is what happens.
There is a transmission rear main output shaft bearing.
Fluid flows back and fourth through that bearing to lubricate the U-joint and the front and rear torque tube bushings.
When the U-joint ball housing is removed and reinstalled.
You fill the ball housing through the speedometer drive gear and top off the tranny case fluid through the side filler plug.
After driving the truck about 10 miles, some of the tranny case fluid will be funneled into the U-joint ball housing.
Which will lower the tranny case fluid level.
Now you should top off the tranny case fluid again.
Until the fluid is leveled off between the U-joint ball housing and the tranny case.

If the fluid is continuously low in the tranny you may have a bad torque tube oil seal.
And the fluid is flowing down the torque tube into the rear axle housing.
One way to determine if you have a bad torque tube oil seal is to remove the axle housing fluid filler plug.
If fluid starts pouring out, that may be a good indication the torque tube oil seal is bad.

Thanks