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Gear Oil Leak

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tomnanney

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I am getting gear oil leaking out of the small hole in the bottom of the transmission after I drive the car. This is a little more than usual. Any idea's on what is happening.
thanks;
 
Perhaps it's engine oil from the crankshaft?
Search "Engine rear oil seal" in this forum.
The transmission can also leak where it joins the bell housing.
 
To figure out from where the oil is coming put some clean paper towels under the weep hole after first cleaning your garage floor. Engine oil will be dirty/black whereas transmission oil will be clear. They will also smell differently--just compare what you have to your dip sticks. Report back....
 
There is an oil seal around the mainshaft that comes from the transmission through the bell housing to the engine. It is simple to replace if you have the transmission out. But as stated above, engine oil is usually black (unless you have recently overhauled and cleaned your block). Clear oil in the bell housing is generally from the transmission coming past the main shaft seal.
 
I did the paper towel under the transmission and it's definitely gear oil. Nice and clear. Not much came out over nightl, however, I'm sure that as it heats up drivings, it leaks as the oil get thinner. So probably a oil seal?
 
tomnanney said:
I did the paper towel under the transmission and it's definitely gear oil. Nice and clear. Not much came out over nightl, however, I'm sure that as it heats up drivings, it leaks as the oil get thinner. So probably a oil seal?
Click to expand...

Well, you shouldn't be running high pressure gear oil--smells like sulfur--in the gearbox and OD. But, if you're convinced that's what is then the seal around the first motion shaft is shot. The gearbox has to come out to replace it.
 
I've always run gear oil 90wt. in the gear box and I've owned the car for almost 40 years. If not gear oil what is recommended?
 
tomnanney said:
I've always run gear oil 90wt. in the gear box and I've owned the car for almost 40 years. If not gear oil what is recommended?
Click to expand...

Shop manual recommends engine oil; 30W non-detergent (up to 20W-50 in later editions). Supposedly, the high pressure (HP) additives in hypoid gear oil are bad for brass components but, if it's worked for 40 years what can I say? There's a difference between GL-4 and GL-5; someone here went over it in another thread. I think one is considered OK and the other is verboten.
 
GL-5 Gear oil is for differentials which have steel gears.
GL-4 Transmission oil is for gearboxes which, at least in the case of our cars, have "yellow metal" or brass synchro rings.
GL-5 oil in a transmission will function but at the cost of the brass as it is more corrosive.
I use Redline MT-90 in the transmission of all my cars.
 
You're welcome Bob.

For a good article on this topic go to: https://www.widman.biz/uploads/Transaxle_oil.pdf and for those of you who don't think this topic to be important pay particular attention to the third paragraph on the second page.
 
Your leak is probably coming past the input shaft seal of the gearbox, but it's also possible to be coming from around the threads of some of the bolts that attach the bell housing to the gearbox. These bolts (two, as I recall) penetrate into the gearbox oil sump. Make sure you seal those threads well whenever you reinstall the bell housing.

Tom, I have your BJ8 included in the BJ8 Registry from AHCA records, but there are additional details I would like to record, if you would contact me directly: sbyers@ec.rr.com.
For the benefit of those who do not know and who might be interested, the registry has added two more "new" cars to the record today, bringing the total now included to 8,533 BJ8s worldwide (48% of total original production).

Thanks!
 
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What I have been using is a Valvoline gear oil that says it meets both GL-4 and GL-5. It's been working so far. Any thoughts?
 
tomnanney said:
What I have been using is a Valvoline gear oil that says it meets both GL-4 and GL-5. It's been working so far. Any thoughts?
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Tom--

With respect, my thoughts are that you did not carefully read the paper cited in my post above. Again, go here: https://www.widman.biz/uploads/Transaxle_oil.pdf for an answer to your question.

There are a couple of Valvoline gear oils carrying that "dual rating" but if for example you look at the product information sheet on their Durablend gear oil (https://www.valvoline.com/pdf/durablend_gear.pdf) you'll see that for synchromesh transmissions Valvoline specifically recommends a an MTF or Manual Transmission Fluid which is stated to be compatible with yellow metals.
 
I've had similar issues on a customers car with slight transmission leaks. The last was on a BJ8, I cleaned the underside of the transmission, went for a drive, then blocked the drip hole best I could. I lay under the car waiting and after a short time I noticed oil which had come out further back along the transmission. It was running down to the lowest point before dripping off. I traced it to a weeping gasket. Cleaned the area and mixed a small bit of epoxy putty and then blocked the hole. Once hardened I painted it Healey Green. The hole was originally too small to put a needle into.
 
TimK said:
There is an oil seal around the mainshaft that comes from the transmission through the bell housing to the engine. It is simple to replace if you have the transmission out. But as stated above, engine oil is usually black (unless you have recently overhauled and cleaned your block). Clear oil in the bell housing is generally from the transmission coming past the main shaft seal.
Click to expand...
I am looking to replace the oil seal around the input shaft. I assume I need to remove the bell housing to get proper access?
 
You have to remove the gearbox/OD, but you don't have to split the bell housing and gearbox (seal is housed in the bell housing). Note BN4s and BN6s don't have a replaceable seal.
 
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