Oil Leak from Bottom of Bellhousing

[alpiner]

After taking a drive in my Series V there is a steady oil drip coming from the drain hole in the bottom of the bell housing that bolts the gearbox to the rear of the engine. It stops dripping after a few minutes with the car parked and leaves a 4" round oil spot under the car. I'm thinking this is the result of a gearbox front seal leak. Anyone with similar experience and suggestions on how to confirm without removing the gearbox? Other than the embarrassment of leaving oil stains wherever I go, is this a repair I can delay? I'm not anxious to tackle a gearbox removal in the near future.

 

[mikephillips]

Could be since the transmission uses engine oil rather than heavy gear type. But it could also be from the rear of the engine where the crank comes out. The Alpine doesn't use a rubber lip type seal but instead has a reverse scroll designed to fling oil beck into the engine. You can get it from there if the engine is getting tired and pressure is higher in the crankcase, or if it is overfilled. This assumes the cover plate on the lower part of the bellhousing is still in place to force any leakage to the inside rather than dropping free from the rear of the engine.

You may be able to tell if the transmission input seal is going of you can borrow one of those bore scopes and go in through the drain hole or around the clutch arm. But since a fix requires removing the transmission, might be just as easy to go ahead and do that. If you do, look at the condition of the clutch bits too, might as well cover all the bases while apart.

 

[CptTom]

I experienced the same problem last year. The problem was the transmission input shaft seal. As the car is fitted with overdrive, the repair required the removal of the engine. You may be able to confirm the source of the leak by the color of the oil. Collect the leakage and compare it with the color of the motor oil. My experience has been that the transmission stays clear and light in color while the engine oil tends to discolor based on usage. Good luck

 

[RootesRacer]

The trans uses motor oil, you might get some more life out of a leaking seal by draining and refilling with high mileage motor oil which contains seal swelling agents. You could also put half a bottle of stop leak (also a seal sweller) in the trans without hurting it.

 

[hartmandm]

I use Brad Penn oil in my engine and conventional oil in my gearbox. The Brad Penn oil is a green color and the gearbox oil is brown. That made it easy for me to know that my bell housing drip is engine oil.

Mike

 

[beamdream]

The trans uses motor oil, you might get some more life out of a leaking seal by draining and refilling with high mileage motor oil which contains seal swelling agents. You could also put half a bottle of stop leak (also a seal sweller) in the trans without hurting it.

Just thinking that if its an OD trans, I'd think twice before putting any additivs in.

 

[RootesRacer]

Just thinking that if its an OD trans, I'd think twice before putting any additivs in.

I didnt see mention of it being an OD, but yeah, if its an OD better just fit it.

 

[alpiner]

Thanks guys. I do not have an OD. I recently switched the gearbox oil from 90 wt. gear oil to the 5-40 wt.engine oil spec. I had not realized the gearbox took the same oil as the engine. Since the leak did not occur, until I put engine oil in the gearbox, I think I'll switch back to the 90 wt. gear oil in the gearbox and monitor the leak. Is there any issue with using 90 wt. gearbox oil in the gearbox? I do have the cover on the front of the bell housing so it could be engine oil. I'll find out once I put the 90 wt. gear oil in the gearbox.

 

[RootesRacer]

Thanks guys. I do not have an OD. I recently switched the gearbox oil from 90 wt. gear oil to the 5-40 wt.engine oil spec. I had not realized the gearbox took the same oil as the engine. Since the leak did not occur, until I put engine oil in the gearbox, I think I'll switch back to the 90 wt. gear oil in the gearbox and monitor the leak. Is there any issue with using 90 wt. gearbox oil in the gearbox? I do have the cover on the front of the bell housing so it could be engine oil. I'll find out once I put the 90 wt. gear oil in the gearbox.

The gear oil is not a great idea, some gear oils have sulpher high pressure additives that can attack certain metals like brass (which is in the transmission).
Also the 90 versus 5-40 rating is apples and oranges since gear oil is tested differently than engine oil (IIRC 90w gear oil is like 50w engine oil in terms of apparent viscosity). I would drain the gear oil and replace with 20w50 engine oil and half a bottle of engine stop leak (or if you can buy it, 10W50 for high mileage vehicles which has seal sweller in it).

 

[alpiner]

Thanks for the advise. I will give it a try.

 

[venice532]

Hi Alpiner, the same exact thing happened to me about 2 months ago.

I have an OD series 5 and even though the trans shifted fine I decided that an oil change was in order.
The oil that I drained out was definitely higher viscosity than regular engine oil.
I decided to use non detergent 30w and after the first drive I noticed the factory spec 4" diameter puddle of oil under the bell housing drain hole.
I have the front trans seal I got from SS sitting on a shelf waiting for the day I have the urge to get my hands dirty.
Lots of work to replace one little seal.
Bob

 

[alpiner]

Thanks for the input Bob. I too am not anxious to pull the engine and gearbox or drop the gearbox from under the car. I've done it both ways in the past but as an older/wiser person crawling under the car is too hard at my age. lot's of work.