1954 Series 60 Leaking only when in reverse

[sgcoupe]

I have a 1954 Series 60 Fleetwood that runs and drives beautifully.  Lately, I have noticed some oil spots on my driveway garage floor and tried to find the source.  The leak is coming from the area where the engine and transmission meet and it appears to be engine oil.
The first time I noticed this on my garage floor, it leaked right after I parked the car and then stopped, making a spot about as big in diameter as a baseball.  The engine and transmission dipsticks still read full.  I pulled the car out of the garage and left it idling in the driveway and it did not leak.  I drove it for 15 miles or so and stopped about halfway to look under the car, nothing.  Same thing when I stopped in the street in front of my home, nothing dripping at all.
I was surprised when I backed the car up the driveway and into the garage that I had a second set of drips on the driveway and when I looked under car in the garage, it was making another small oil spot on my floor.  The same things has happened on 2 more occasions.
The fluid is brown and thicker like engine oil, not thinner like transmission fluid.  Both dipsticks still read full, so it appears this is a leak that only happens when the car is in reverse.
Anybody familiar with these transmissions have a suggestion??

[gary griffin]

This post would get more attention in the Technical ? Authenticity section of the Forum.

Having said that a better investigation of the fluid is needed. It sort of sounds like a rear main seal rather than transmission leak. I bet the engine is warm when you back up and park?  Warms lubricants run easier than cold ones. I would try a clean paper towel to pick the oil up with out getting it dirtier than it already is and wiping the dipstick form the engine on one side of the stain and from the transmission on the other side and comparing them. That may give you an idea of where it is coming from??

[sgcoupe]

Thanks Gary. 
I can drive the car for 60 miles and park it with the engine idling and it will not be leaking oil on the ground.  At the rate it leaves spots on my driveway, the dipstick would be low if it dripped when the engine was hot.  I've put several hundred miles on the car since I first noticed this.  As soon as I put the car in reverse, it begins dripping as evidenced by the "Hansel & Gretel" oil spots on my driveway from the spot I put in in reverse all the way up my driveway to the garage.
I did not think about using a paper towel for comparison of the oil and transmission fluid.  I'll definitely do that when I get home tonight.

[walt chomosh #23510]

Gary,
  I had the same thing happen to my 55CDV. It was the gasket between the trans main housing and the tailshaft. Simple gasket,but a big job changing it!....walt...Tulsa,ok

[sgcoupe]

Walt, was it leaking engine oil or transmission fluid? 

I took Gary's suggestion and verified it is (brown) engine oil and not (red) transmission fluid by pulling each dipstick to be sure. I can't think of why it only leaks engine oil when in reverse and I have crawled down to look under it several times after driving around. The dipstick being full tells me it can't be leaking all of the time.

[55 cadi]

Steve,

As far as the dip stick not showing it low.....i have a rear main seal leak, kinda bad too, but when i check the dip stick it doesn't show that it is very low.....until at one point the rockers rattle and then it shows low. 
So you may be low but it doesn't show on dip stick until your LOW like mine.

Just a thought.

Jason

[savemy67]

Hello Steve,

Reading your posts leads me to believe that you only notice the leak when the car is in reverse gear in your driveway.  Also, from your posts, it sounds like your driveway is an incline.  Have you tested for a leak in reverse on level ground?

I would think it highly unlikely that the engine would leak oil only when the transmission is in reverse gear, as the engine is always rotating in the same direction.  It seems more likely that a leak might show up if the car was on an incline.  Are there any weep holes in the bottom of the bell housing on your '54?  If there was a rear main seal leak allowing engine oil to accumulate in the bell housing, the oil may dribble out of the weep holes only when the car is inclined at a particular angle.  A small amount of oil can look like a large amount when it spreads out on a driveway.

Respectfully submitted,
Christopher Winter

[walt chomosh #23510]

Steve,
  May I suggest putting the car up on blocks and getting under it for troubleshooting purposes? Do an actual visual check with it running and in reverse.....walt....Tulsa,ok

[sgcoupe]

Christopher,

I think you may be on to something.  There is a small incline at the very end of my driveway by the road.  I haven't had this thing up in the air yet and it sits too low to the ground to really see the design of the bell housing, etc.  But, your explanation makes sense.  I have a small oil leak that isn't enough to notice until the car is tilted in such a way as it empties out the accumulated oil which drips off as I am backing up the driveway.

It's not uncommon for old cars to leak oil, but this car is new to me.  My main concern is that I wasn't naively ignoring a bigger problem that may be unique to these.  As I said, the dipstick is right near the full mark so I was pretty sure that I may have lost 3-4 ounces at the most.  I'll have an oil change done when the season is over anyways and can look at the underside wehn they have it up in the air.

I appreciate the insight!

Steve