oil leak

[clumzyfly]

yesterday I was driving down the road and my lifter tick(as it has been determined on this site) got louder and louder until it sounded like there was no oil in the truck. I pulled over and looked under the truck to see a decent oil leak coming from where the engine meets the tranny. I put 4 qts oil in the truck to bring it back to the full level and drove it the 20 miles home. By the time I got home, there was no oil even showing on the dipstick. I'm guessing this is the main rear seal? Is it easier on these trucks to pull the enging, pull the tranny or can you do it easily by just pulling the tranny toward the back of the truck. Like I said, I haven't had the chance yet to get under there and really look at it yet, but I do know the oil is dripping from where the engine and tranny meet. Any help on this would be appreciated.

[clay78w150]

clumzyfly you may want to let us know what year and engine.

[OLD DODGE]

Assuming its a small block, the oil pressure sensor is by the distributor where the back of the block meets the transmission. These are prone to leak and would empty your oil pan quicker than a rear main seal. Easier to fix also.

Good luck!

[712edf]

Same location for a big block too. Also there's oil passage plugs in the back of the block inside the bell. I've never heard of them coming loose and leaking.

How you approach replacing the rear main seal kinda depends on vehicle, engine/transmission & if you have access to a car lift.

[Ron in Indiana]

I would by a can of degreaser like GUNK and hose the engine down to clean it up to see better where the oil is coming from. If it's losing this much oil it shouldn't be hard to tell right away. I'd start at the top with the sending unit provided it's a V8 and work your way down while it's running and stationary. Like the others stated it's helpful to know what truck and engine you're talking about.

[clumzyfly]

I'm sorry, I thought I had my truck stats in my signature...
1976 M880(W200) 318 engine auto tranny(not sure what kind....stock I'm sure)


I don't have access to a car lift, I may have access to a motor lift...but not a guarantee.

QUOTE
"Assuming its a small block, the oil pressure sensor is by the distributor where the back of the block meets the transmission. These are prone to leak and would empty your oil pan quicker than a rear main seal. Easier to fix also."

I've never had to deal with that before, how would I go about fixixing that?

QUOTE
"Also there's oil passage plugs in the back of the block inside the bell. I've never heard of them coming loose and leaking."

I had this happen on my 77 VW Bus. It emptied the oil in about 30 seconds and locked the motor so I had to rebuild.



I'll check more into it hopefully soon.

[clumzyfly]

I didn't have time to look at it, but I had a friend check int it and he said it was either the rear main or the oil pan gasket. since the oil pan gasket was the easiest I went ahead and let him do that. It was definitely bad..the rear rubber piece was in three pieces. That slowed the leak some, but it is still leaking very badly. He said you have to pull motor to change the rear main on these trucks....is this true? Is there no way of doing it without pulling the motor?

[712edf]

rear seal

The rear main seal I believe is two piece, an upper half & a lower half. To get the upper half of the old one out you have to loosen the main caps and lower the crank a hair. If the engine is still in the vehicle on jackstands with everything still hooked up (convertor, front pulley, balancer, timing chain & cover, all rods, etc) and only the pan and pump removed, I don't see how one can get that upper half removed/replaced. Maybe a professional can, I don't know. I have replaced a crank with a motor still in the car (ford ltd 351) but I was a teen and honestly don't remember what was involved.

The lower half of the rear main seal is a piece of cake.

I wouldn't attempt the job without the truck up on a lift. My crawling days (& drinkin') are long past.

[clumzyfly]

I believe the lower half is what is leaking...would I be able to just replace the lower half to test this theory before pulling the engine and going through all that trouble? Or do both halves have to be replace at the same time?

[712edf]

To replace lower half of thr rear main seal just drain oil, drop pan, remove pump IF its in the way (not sure, I'm a 440 guy), remove rear main cap.....you're there!

[Ron in Indiana]

If memory serves I believe you can replace the rear main seal on a 318 without pulling the engine. It should have a two piece neoprene seal that once the rear cap is removed can be pushed/pulled from around the crank. There is a seal puller tool to help with this. Once you have the old one out you push the new one in place. Then just drop the other in the cap and retorgue to specs. Pick up a seal and check it out you have to have one anyway. This shouldn't reguire the loosening of the other caps.

[clumzyfly]

thanks guys..I believe Thursday will be the next chance I get to do anything with it.