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TR4/4A Leaky Overdrive

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shoopal

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I don't know if anyone can help me but humorous replies will be a welcome diversion.
A few months ago I rebuilt my Type A overdrive. I filled it with 80 weight gear oil and it sat, mated to the engine on my garage floor for about 6 months. No leaks. A few months ago I hauled it over to the body shop and it sat there with no leaks. We installed it (tranny top cover off) about a month ago. When I came to pick it up yesterday, a huge puddle of gear oil was under it. At the moment there is no transmission cover over it and the yoke horse collar is not installed yet so I can get it out fairly easily. Bell housing and rear mount and its good to go.
I appears that it is leaking from the corner where the overdrive solenoid cover meets the Trans/OD adapter. Obviously I used new gaskets and I also gooped those joints liberally with the brown permatex gasket stuff.
I was hoping that when we tipped the unit to clear it for installation, some oil may have leaked from the missing top cover into somewhere where it is now leaking from, but this seems to be a forlorn hope.
Thanks for your sympathy
Al
 
I have a rebuilt but leaky OD in my TR3 which I discovered after the install. It was coming from a mating surface between the trans body and the OD assy (IIRC). I slathered silicone on the joint after tightening the mating bolts as much as I dared but it still leaked....so.....I built a catch basin that holds an 'oil diaper' in it and strapped it up to the offending area. I then cut a nice hole in the trans cover, plugged by an extra floor (jack) rubber. I can service the diaper from there.

In three years' I've only had to replace (squeeze) the diaper once. That reminds me, I should check it today. (I can also drop the assy with two screws if I want to look closer).

Thom
1959 TR3 #TS34909L(O)
 
Yow. What a fix. After a closer investigation, it appears that it is leaking from the side cover and the trans/OD adapter plate as you suggested. I've got the trans/OD unit out now and I guess that I'm going to check mating surface alignment with some blueing before I re-assemble. Aluminum will warp. The only thing I'm worrying about now is getting the pump plunger over the cam.When I assembled it the last time, there was a scary pop but plenty of pressure on testing. I don't want to do that again. If someone has a trick for holding the plunger away from the cam, I'd like to hear about it.
 
Al-It seems that some of the adapter plate gaskets are quite thin and more prone to leak than others. The last time I had the OD apart, I made one from 1/32" Victor Reinz gasket material and used the Hylomar clone sealer. The old brown non-hardening sealer from Permantex didn't live up to its name. Other possible culprits for leaks are the drain plug. Sometimes it is necessary to use 2 gaskets and don't overtighten as the fiber washers as they tend to split. Also, the plug can loosen and cause a leak.
After breaking a pump plunger, I discovered that the OD can be mated to trans., then the plunger and pump body put into place. It eliminated the possibility of snaging the plunger on the pump cam.
Berry
 
I eliminated the drain plug as the culprit before I pulled the trans/OD out. Yes the permatex was very disappointing. I used it in a number of other places and now I wondering about how well they will hold up.
Anyway, I just ordered the new gaskets, so I'll wait to get them before I start.
Thanks for the plunger/cam trick. I'll definitely do that
 
I was massively careful and meticulous on OD rebuild. It leaks. I removed the side plate and resealed it. It leaks. I give up. I check the OD every few months.
 
I'm going to try the solution from "Titanic". I checked up on the Hylomar stuff. Impressed. There seem to be a number of variations including one that has a permatex label which makes me suspicious. Which one to choose?
When I rebuilt it last year, it sat on the garage floor and didn't leak a drop. It was after I put the engine/trans/OD into the car that it started. My theory is that the brown non-hardening permatex did harden and the stress on the joins with the engine up in the air and the OD dangling off the end, cracked the now hardened permatex and initiated the leak.
When I split it to change the gaskets and reseal, the question may be answered
 
titanic said:
Al-It seems that some of the adapter plate gaskets are quite thin and more prone to leak than others. The last time I had the OD apart, I made one from 1/32" Victor Reinz gasket material and used the Hylomar clone sealer. The old brown non-hardening sealer from Permantex didn't live up to its name. Other possible culprits for leaks are the drain plug. Sometimes it is necessary to use 2 gaskets and don't overtighten as the fiber washers as they tend to split. Also, the plug can loosen and cause a leak.
After breaking a pump plunger, I discovered that the OD can be mated to trans., then the plunger and pump body put into place. It eliminated the possibility of snaging the plunger on the pump cam.
Berry
Click to expand...
I tie the plunger down by looping a thin wire or some string through the oil return holes in the pump sump. Once assembled I cut and pull the wire or string out. Simple and does not involve removing the pump body which can be damaged in the process.
 
That is the method recommended by https://www.buckeyetriumphs.org and is what I did myself. The problem is that the string must have stretched because it hung up on the cam a bit but popped into place when I set up on the bolts (scared the H out of me but I guess it survived).
 
I'm pretty much a novice on ODs and I'm uncomfortable rebuilding transmissions, but Permatex #2 has never hardened or failed to seal for me with the right gasket. I'm guessing that while sitting on the floor there was no stress or pressure, but once installed that all changed. Some of the gaskets from the usual sources leave a lot to be desired and I've made my own when a leak persisted or mating surfaces were not perfectly flat.
Rut
 
shoopal said:
That is the method recommended by https://www.buckeyetriumphs.org and is what I did myself. The problem is that the string must have stretched because it hung up on the cam a bit but popped into place when I set up on the bolts (scared the H out of me but I guess it survived).
Click to expand...
Try using a soft wire next time, being soft it will pull out easy. My problem has always been aligning the splines at the end of the short shaft.
 
The problem with the Permatex hardening seems to take many years and heat cycles. The issue of the difference in thickness of the adapter plate gaskets is mentioned in the Buckeye articles.
The wire technique for holding the plunger is place does work, but I stumbled on to the alternative when dealing with the OD from ****. Now, I just fit the pump body/plunger after the OD is mated to the trans.
You got have a sense of humor when dealing with British cars, especially when attempting to cure oil leaks in A type ODs. They never stay leak free for long.
Berry
 
An update: I removed the OD from the trans, cleaned off the old gaskets which had kind of disintegrated, and threw some black paint on the trans side mating surface. Leaving out the springs and figuring out how to wire down the pump, I reassembled it. After removal the paint smudges showed the highs and lows. Reassembling it and using my .003" feeler gauge, I could not find anywhere the gauge would slip in. The paper gasket is way thinner than .003 and doesn't really compress much.
I believe the 1/32 (.03125) thick composition gasket (10 times thicker than my gauge) plus the hylomar will do the trick.
fingers crossed
 
If you missed my post last week...I placed the Oring for the operating shaft on the outside of the cover...instead of the inside. Doh! It was a similar deal. My OD sat filled for 3 years with no leaks. As soon as I put it in the car, it started leaking from the shaft.

I popped the cover, swapped the Oring to the inside and closed it up with the same gasket, but used permatex 518 on the used gasket. The leak is gone. The 518 will dissolve if it squeezes to the inside of the OD.
 
I just looked at the moss diagram of the OD and it shows 2 O-rings on the shaft which has confused me.
 
JerryVV said:
I tie the plunger down by looping a thin wire or some string through the oil return holes in the pump sump. Once assembled I cut and pull the wire or string out. Simple and does not involve removing the pump body which can be damaged in the process.
Click to expand...

Im with Jerry- works well and easy to do.
 
shoopal said:
I just looked at the moss diagram of the OD and it shows 2 O-rings on the shaft which has confused me.
Click to expand...

The reason I initially put the Oring on the outside is because that is where the illustration in the OD manual shows it!! The illustrations are not always correct...or can be misleading.
 
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