VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1912-1928 1927 Chev - Transmission Leaking

Hi Everyone,

Our '27 sprung a transmission leak. It's leaking into the clutch bell housing, and out via both the bottom of the clutch housing and via the clutch fork opening. The leak is definitely coming from the transmission and not from the engine as it is 600W oil that is leaking out. No mistaking the consistency of the oil, and as such, it must be coming from the transmission. The leak is pretty bad and we likely are dripping out about a 1/4 to 1/2 a cup each time we take the car for a short drive.

I am guessing I know the answer to this, but is there an easy fix or must the transmission be dropped to resolve this one ?

As some of you may know from prior posts, we are newbies' and this a Father / Son project. Dropping the transmission is likely out of our league...

Any ideas & advice would be greatly appreciated. Here is a link to some pictures:

https://plus.google.com/u/0/photos/103109131679997921712/albums/5876541596247824593

Thanks - Chuck & Brad

Hi Chuck & Brad,

A transmission leak will most likely require the removal and opening up the transmission. The transmission can leak at the front bearing. Replace the bearing with a sealed bearing. Remove the inner seal. The two shafts may be leaking. Open, clean out everything, purchase the rebuild kit with the two shafts. Apply fuel tank sealer on the new shafts. Can be leaking at the rear with the oil gravitating to the rear end. Use a sealed bearing at that location and again remove one side and face it toward the center of the transmission.

Take the top off the transmission by removing the 4 screws. Throw a rag over the inside parts to keep the dirt out and it will be much easier handling.

Hi Ray,

Thanks very much for this info.

Assuming we keep the transmission filled, can we continue to drive the vehicle as is ?

Are there any other options that we can try to resolve the leak, without pulling the transmission ?

We have both the repair and owners manuals for the car, but I have been trying to find some additional detailed information and photos of the job (pulling and rebuilding the transmission), but so far without success.

Any ideas where best to purchase the parts? The Filling Station has them, but not sure that's our best option.

Thanks Again.

It would be helpful to find out where the transmission leaks. Suggest you do a major cleanup of the transmission and surrounding area. Make short trips and inspect where the leak is coming from. Also inspect the fluid closely to determine where it came from, is it a very heavy oil or is it light oil from the engine? Once we decide where it is coming from we can make a plan of attack.

If the gearbox hasn't been overfilled,there may be the possibility that the oil is leaking past one or more of the flywheel housing the gearbox bolts along the threads.

We have confirmed that the oil is not coming from the engine, and is definitely 600W oil from the transmission only. The oil leak is coming from two major areas:

-From the drain hole with cotter pin at the bottom of the clutch bell housing.
-From the side of the bell housing, where the clutch fork protrudes.

Chuck

Could you please remove the fill plug, check with your little finger, and insure the oil level is correct.

Based on your previous posting your problem is either overfill or the transmission must be removed and the front shaft bearing replaced with a sealed bearing with the inside seal removed.

Let's hope it is just overfilled.

Hi Ray,

We pulled the fill plug and checked for oil, but as far as I could put my index finger in, the reservoir was dry. Here's a picture of the "fill hole" I am referring to.

https://plus.google.com/u/0/photos/103109131679997921712/albums/5877662068942658385

We had topped the transmission up to the top of this "fill hole" until the transmission wouldn't take any more oil prior to it leaking. We had read the manual and had thought we were filling the transmission correctly, and used old school 600W oil we purchased from an Antique Automotive place here locally. It was about 50 miles of driving after we filled the transmission up that it started to leak from the clutch bell housing.

I also took a few pictures with the top of the transmission off. The gears all look good with no visible damage or wear etc.

Unless you have a cracked transmission case I think your problem is that the oil is not being retained by the front slinger. This calls for replacing the input shaft bearing with a sealed unit and knock out one side.

Have you checked closely the holes in the transmission for the two shafts? Wipe clean with solvent and dry the area and watch all 4 areas for leaks.

Hi Ray,

Apologies for the simple questions here, but which part is the "front slinger" ? I have checked the repair manual, but dont see that part referenced.

To check the shaft holes (as per the second sentence in your note), should i be checking the outside of the transmission, or going in from the top with gear shift removed? To check all four holes for leaks, must the transmission be removed?

Again apologies for how basic these Q's are.... Thx.

Chuck

By all means, as Ray has mentioned, put a sealed bearing in the front of your gearbox, but DO NOT put a sealed bearing in the back of the box as the oil must flow thru to lubricate the ini joint.
BTW Judging by the photos, it looks like the spigot shaft, the one that goes thru the clutch plate, is from a 29 gearbox, as it has steps in the rear splines. Not a big deal, but I think they are slighly shorter in length.
Chris

Just wanted to provide everyone with an update on this. The problem is now resolved.

VCCA member Ron1967 sent us a whole bunch of pictures and provided a ton of advice via email, and his advice, combined with the information & advice provided by many members here, gave us the confidence to pull the transmission and have a look.

Well, as it turns out the prior owner (or someone) had installed the transmission without any gaskets...no wonder it was leaking like a sieve!

Here is a link to some pictures that shows what we found: https://plus.google.com/u/0/photos/103109131679997921712/albums/5880176757140519265. The key picture to view is the one that shows the transmission support member separated from the case.

After re-installing the unit, we have taken the car for three good rides totalling about 70 miles and so far no leaks to speak of. Looks like the lack of gaskets was the issue.

Brad and I can't thank everyone enough, especially Ron1967, for all the help. We never would have been able to take this job on without your collective assistance and support!

Cheers,

Charles & Brad

Earlier in this thread, there seemed to be two pieces of advice that are conflicting:

1. AntiqueMechanic said, "Can be leaking at the rear with the oil gravitating to the rear end. Use a sealed bearing at that location and again remove one side and face it toward the center of the transmission."

2. Then, chevguroo said, "as Ray has mentioned, put a sealed bearing in the front of your gearbox, but DO NOT put a sealed bearing in the back of the box as the oil must flow thru to lubricate the uni joint."

Here's my dilemma: The 600W oil that I put in the u-joint of my '28 flows into the tranny and overfills it, thus setting the stage for leaking.

I'm going to pull the tranny and replace the bearings and gaskets.

Do I put a sealed bearing (with one side/seal removed) in the rear tranny position or not? I notice that the front bearing that the Filling Station carries is sealed, but the rear bearing is not.

Thanks, Dean

A follow-up question would be, if I should put a sealed bearing in the rear of the transmission, what is the bearing number/maker for this bearing?

Thanks, Dean

A sealed bearing for the transmission input shaft with inner seal removed is okay. Sealed bearing at output shaft is not recommended. The lube needs to be able to flow from the transmission to U-joint. If the torque tube seal leaks then the lube will eventually reach the rear end. If so just check occasionally (experience will tell you correct timing) and put excess from rear end into transmission.

If the lube put into the U-joint ball housing is overfilling the transmission it is also overfilling the U-joint.

Thanks, Chipper.

I was under the impression that the u-joint cavity needed to be 'full', but if the oil level is the same as in the tranny, then I guess the u-joint has 'enough' oil.

Cheers, Dean

Only takes a little in the bottom of the ball housing to splash around and lube the U-joint and front torque tube bushing.

Makes sense.

Thanks again, Chipper! Dean