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MG MGA - Redline MTL in my tranny

Some time ago in a discussion of synthetic oil for the tranmission, Reline oil was suggested as a much better alternative. One of the individuals praising the results of this product was Martin Straka.

After a rebuild I decided to use this product even though the cost was just over $12.00 a quart. I don't know if it's performance is really better than regular oil but my concern is that despite all my efforts, there is still some leakage. There always is a drip coming off the oil plug.

My question is whether to continue using this expensive oil and keep losing oil and refilling the tranny or to go back to regular oil. If I chose to go back to regular oil would there be a problem mixing regular oil with whatever Redline remained in the tranny after draining. I'd welcome any comments or suggestions.

J. Hudrlik

It shouldn't be leaking. Use Teflon tape or pipe dope on the threads of the plug to stop it.
Bill Spohn

Bill:

Thanks for the suggestion. I have done this without any difference in the leak. I have also re tightened all the nuts on the cover that are accesable.
J. Hudrlik

JH, it could be that the oil is not actually leaking from the plug, but as the plug is the lowest point on the gearbox, oil is migrating there from somewhere else. Even oil from the engine could find its way back there (mine does!). If the oil drip is clean, it is from the gearbox, if the oil is dark, it is from the engine. If your gearbox oil level is not dropping significantly it's probably not worth worrying about. I think it is OK to mix ordinary mineral oil with synthetic, but no doubt someone will correct if I am wrong. Personally, I would stick with using the same oil in the gearbox as is used in the engine and change it at the recommended 6,000 miles. My standard gearbox works beautifully on Castrol XL 20/50.
Lindsay Sampford

I tried Redline MTL with similar results. Since it's red in color it's easy to determine it's not motor oil on the floor. There's no issue with mixing it should you decide to go back. I did. As the Redline went down, Castrol 20x50 went in and almost over night the leaking began to diminish. I know I need to replace the rear seal on my gearbox, so that probably accounts for what's leaking now. Want a comparison - in 500 miles with Redline I lost nearly 2/3 of a quart. I just did another comparison after replacing that loss with Castrol and did not have to add any! Bottom line, Redline is too thin for the way most of our car's gearboxes seal up.

Another alternative to using thread tape is a ”stat-o-seal washer". It is a metal washer with a built in rubber washer inside of it. I install a 5/16" on the nut that attaches to the stud on the lower side of the gearbox and it's worked great (got the tip from a vintage racer).

Here's another tip to find where your gearbox leaks from. Wipe the entire bottom and sides good to remove any oil. I gave mine a shot of cleaner as well - carb or brake cleaner - to ensure it was really clean. Then I packed some white paper towel into the top & sides which held paper towel to wrap around it like a diaper. In no time it pin pointed exactly where the leaks were. I had two. One from the nut mentioned and one from the rear seal.
D Quinn

Often oil weeps down the threads of the side cover, so using a little sealant on these helps reduce oil loss.

I have a ford box in mine which is leaving traces on the floor too....
dominic clancy

Hey Quinn, your idea of pinpointing the leak is a great idea. I assume that you didn't drive the car and lose the paper towles but let it sit a while after packing and then discovered the leak.

Thanks
J. Hudrlik

Dominic;

This is one of those situations where I find myself thinking - oh why didn't I do that before I reinstalled it in the car. Unfortunately I can't get at all the cover fasteners while the tranny is still in the car.

Thanks, Jerry


And thank you too, Lindsay
J. Hudrlik

My rear seal leaks, but I found that I could reduce the oil loss a lot by parking carefully. I always make sure that if I have to park on a slope, the front of the car is pointing downhill!
Lindsay Sampford

couple comments...

Yes, the paper towel trace does not take long..... generally a day or two is all you need and you can spot exactly where it is coming from. If you remove it too and still are not quite sure, just redo the process and leave it on longer to validate the specific location.

My car leaked more out the tail while on jack stands than on the ground; I'm sure it had something to do with the angle it was at.
D Quinn

This thread was discussed between 03/08/2011 and 05/08/2011

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