Something’s Leaking - escaping, oil / fluid-wise. Thoughts?

[dllubin]

Have you checked the low oil pressure warning light sender on the front of the head? It can end up leaking in that direction. I had a leaking banjo port duplicator there and it was pretty much leaking just like yours - shift linkage and all. The shift rod seal could be suspect as Dan suggested. My first one lasted about 40K which means at 81K mine may be living on borrowed time.

 

[tvmaster]

Have you checked the low oil pressure warning light sender on the front of the head? It can end up leaking in that direction. I had a leaking banjo port duplicator there and it was pretty much leaking just like yours - shift linkage and all. The shift rod seal could be suspect as Dan suggested. My first one lasted about 40K which means at 81K mine may be living on borrowed time.

The oil pressure sending unit needs replacing I believe, but that doesn’t leak transmission fluid to my knowledge. When you say the front of the head….could you elaborate? Still learning terms. Don’t know what a banjo is either

 

[dllubin]

The oil pressure sending unit needs replacing I believe, but that doesn’t leak transmission fluid to my knowledge. When you say the front of the head….could you elaborate? Still learning terms. Don’t know what a banjo is either

Sorry. It is actually on the block just below and between #2 and #3 spark plug. It is quite a bit closer to where your leak is than the oil pressure sender. You should not have a banjo port duplicator on your engine as the 1300 in the 74 already has a port for each type of oil sender. The oil pressure gauge was gone by the time the 1500 came around and most of those blocks were not drilled for the oil pressure gauge - thus the need for the banjo on my 1500.

 

[tvmaster]

Sorry. It is actually on the block just below and between #2 and #3 spark plug. It is quite a bit closer to where your leak is than the oil pressure sender. You should not have a banjo port duplicator on your engine as the 1300 in the 74 already has a port for each type of oil sender. The oil pressure gauge was gone by the time the 1500 came around and most of those blocks were not drilled for the oil pressure gauge - thus the need for the banjo on my 1500.

Ok, I’ll look for the sender light wire. Thanks.

 

[Dan Sarandrea (Phila)]

The shift boot may be seaping a little, but the nut just behind it constantly is filling with fluid and then running down the support bar and dripping off the bottom of the support bar four inches away. What is this nut supposed to be sealing (The nut above the yellow arrow). I’ve dried that nut and then watched in real time as fluid begins to surround it.

OK that info helps.

Notice that the "leaky nut" in question is on a stud that protrudes from the transaxle case, while it's partner securing the transaxle case to the engine crossmember is a capscrew? This was done on purpose by the engineers because the threaded hole for the stud has to be a controlled depth; it cannot be too deep or else the fastener in that hole will break thru into the case and in extreme situations possibly impinge upon the shift operating rod. They could have just used a short capscrew, but they knew that out in the real world not every mechanic is the best at putting the exact correct capscrew back into exactly the correct hole.

I recall Steve Hoelscher, a longtime member of this forum and undisputed King of X1/9 transaxles, relating this explanation many years ago.

It's possible that when the engine and trans were removed and then replaced, someone did not know the limitation above and ran the stud too deep into the case and created a direct path thru which transaxle oil can seep.

You can conduct an easy experiment to see if this is the problem. Place a catch pan under the suspected area, double-nut the stud, and then unwind the stud out of the transaxle. If the transaxle oil starts flowing out like a drain, then you have discovered the issue. The solution would be to let it drain, clean the area and the threaded hole as best you can, then apply a good teflon sealer or teflon tape to the stud threads to seal it up.

 

[tvmaster]

OK that info helps.

Notice that the "leaky nut" in question is on a stud that protrudes from the transaxle case, while it's partner securing the transaxle case to the engine crossmember is a capscrew? This was done on purpose by the engineers because the threaded hole for the stud has to be a controlled depth; it cannot be too deep or else the fastener in that hole will break thru into the case and in extreme situations possibly impinge upon the shift operating rod. They could have just used a short capscrew, but they knew that out in the real world not every mechanic is the best at putting the exact correct capscrew back into exactly the correct hole.

I recall Steve Hoelscher, a longtime member of this forum and undisputed King of X1/9 transaxles, relating this explanation many years ago.

It's possible that when the engine and trans were removed and then replaced, someone did not know the limitation above and ran the stud too deep into the case and created a direct path thru which transaxle oil can seep.

You can conduct an easy experiment to see if this is the problem. Place a catch pan under the suspected area, double-nut the stud, and then unwind the stud out of the transaxle. If the transaxle oil starts flowing out like a drain, then you have discovered the issue. The solution would be to let it drain, clean the area and the threaded hole as best you can, then apply a good teflon sealer or teflon tape to the stud threads to seal it up.

Wow, never would have guessed this in a million. Thanks. Except for the solution part: “double-nut the stud” Explain please for the newbie Here’s a better pic:

 

[tvmaster]

Sorry. It is actually on the block just below and between #2 and #3 spark plug. It is quite a bit closer to where your leak is than the oil pressure sender. You should not have a banjo port duplicator on your engine as the 1300 in the 74 already has a port for each type of oil sender. The oil pressure gauge was gone by the time the 1500 came around and most of those blocks were not drilled for the oil pressure gauge - thus the need for the banjo on my 1500.

Is this the unit:

 

[Dan Sarandrea (Phila)]

Wow, never would have guessed this in a million. Thanks. Except for the solution part: “double-nut the stud” Explain please for the newbie Here’s a better pic:

View attachment 51285 View attachment 51286

Double nut to remove stud:

 

[tvmaster]

Double nut to remove stud:

Thanks. Eric does good videos. Did you see the fluid on the nut? So the stud may be either too long, or protruding into the transaxle case, correct? Or, the threaded hole has become damaged and is not tight anymore? One thing’s for sure, there’s not much stud to work with.
I’ll let you know the progress, thanks.

 

[dllubin]

Is this the unit:

View attachment 51284

Yes. Looks pretty dry in the photo.

 

[tvmaster]

Yes. Looks pretty dry in the photo.

Ok, thanks. Yes, I don’t believe this is our culprit

 

[NEG]

Don’t discount the leaking drive shaft boots. The oil gets everywhere and makes it difficult to pinpoint any other leak. I’d get them replaced first and then keep an eye for other leaks.

 

[tvmaster]

Don’t discount the leaking drive shaft boots. The oil gets everywhere and makes it difficult to pinpoint any other leak. I’d get them replaced first and then keep an eye for other leaks.

Yes, both the axel boots are on the replacement list, however, the transaxel case stud/nut is an inexpensive first move…

 

[tvmaster]

Apparently this boot has seen better days as well - lol. PO must have missed this due to Covid?

 

[Dan Sarandrea (Phila)]

Wow, never would have guessed this in a million. Thanks. Except for the solution part: “double-nut the stud” Explain please for the newbie Here’s a better pic:

View attachment 51285 View attachment 51286

Actually, I read thru the thread again and whaddaya know, Steve mentioned this in post #24 in this thread!!!

"4 speeds will leak from the inner CV boots at the axles and also at the case seal. The other most common leaks are the main shift rod accordian boot and the transmission mount's stud."

Once again proving (as if we didn't know already) that he is THE MAN.

 

[tvmaster]

Actually, I read thru the thread again and whaddaya know, Steve mentioned this in post #24 in this thread!!!

"4 speeds will leak from the inner CV boots at the axles and also at the case seal. The other most common leaks are the main shift rod accordian boot and the transmission mount's stud."

Once again proving (as if we didn't know already) that he is THE MAN.

Why yes, yes he is. I just couldn't get a camera in there to confirm at post #24. Guess I've got some sealing to do $$$

 

[tvmaster]

Almost any transaxle leak will run to the lowest point and fall from there so its often hard to diagnose a trans leak from where you find the drip on the bottom.

4 speeds will leak from the inner CV boots at the axles and also at the case seal. The other most common leaks are the main shift rod accordian boot and the transmission mount's stud.

Its unusual for the vent to leak unless it is excessively overfilled or excessively over heated (very unlikely in a street car).

Also possible for the main case gasket to leak due to age. 40+ year old case gaskets will lose their resiliency and allow oil to weep through.

The original gear oil will surely appear as brown. New GL1 (factory fill) will appear as almost yellow or a pale brown. Often, fresh gear oil will appear as brown because it accumulated old dirt from the outside of the case as it collected there. Modern synthetics are typically nearly clear unless dyed, which is becoming more common these days.

Hi. Dan has some good advice for repairing a case stud which may be leaking. Anything you’d like to add to repair techniques? I’m pretty sure this is where most of my tranny fluid is exiting from. Thanks.

 

[NEG]

I thought the same bolt was leaking on mine, don’t underestimate the amount of oil leaking from the boots. Since I replaced mine the bottom of the engine and gearbox has remained dry, touch wood! Including the selector drive shaft.

 

[tvmaster]

I thought the same bolt was leaking on mine, don’t underestimate the amount of oil leaking from the boots. Since I replaced mine the bottom of the engine and gearbox has remained dry, touch wood! Including the selector drive shaft.

Yup, those are on the list as well, but based on physics, it does seem fluid is exiting around that stud...

 

[tvmaster]

Well, after two weeks of running and sitting, it’s safe to say the leaks have been stopped!
Thanks to all who tried to help. The oil leak was mostly from finger-tight nuts on the oil pan, and possibly the sending unit, which has mysteriously stopped for now.
The transmission leak seems to have been the stud entering the tranny case. After removing, cleaning, thread-sealing and replacing the stud (with the original stud), there hasn’t been fluid on the garage floor since. Woohoo!. Thanks again