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Roy, ASE Certified Technician
Category: Nissan
Satisfied Customers: 5454
Experience:  Nissan Master technician
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2002 Nissan Altima: It recently started leaking oil..block..exhaust

Resolved Question:

I have a 2002 Nissan Altima. It recently started leaking oil from the transmission housing where it meets the block. This drips onto the exhaust and cause strong odors that get pulled into the car. I have replaced the oil cooler gasket and had the rear main seal and oil pan gasket replaced. The leak is still there. What other items can I check to help find the leak. I ran the engine and looked for leaks around the valve covers and did not see anything.
Submitted: 4 years ago.
Category: Nissan
Expert:  Roy replied 4 years ago.

Roy :


Roy :

Is the oil engine oil or transmission oil ?

Roy :

you could have a axle seal leaking or front transmission seal leakng

Customer: It is a dark brown color. The oil was just changed today when they finished the rear seal. It does not appear red or smell like transmission fluid.
Customer: I also had the oil changed around the 10th of this month and they checked the tranny fluid and did not mention it was low.
Roy :

ok I would have the mechanic that installed your rear main seal recheck it then, it could still be leaking

Customer: It appears to be coming from behind the dust cover on the transmission housing primarily when running.
Roy :

do you know if they removed the oil pan when seal was replaced , this is the correct way to do it , there is also a seal under rear main for oil pan seal.

Customer: The oil pan is on the passenger side of the car and the rear seal that they replaced is on the drivers side. They did replace the oil pan gasket during the process. The seal was a two part seal.
Roy :

ok good

Roy :

I would think if nor rear main leakng you could have a valve cover leaking and oil could go into bell housing of transmission

Roy :

I would still have them check it , to make sure after they just repaired your leaks

Customer: I will take it back to them in the morning for another check. I ran the car and checked for leaks on the drivers side of the valve covers. I did not see any oil leaking out on that side, yet at the same time I could see oil dripping under the car.
Roy :

I would do that then have them show you what they see, just to make sure you see where it is coming from

Customer: Currently the dripping on the exhaust prevents me from running the air on anything that does not use recirc.
Customer: Thanks. I was running out of ideas. Short of the valve covers I could not think of any other seals or gaskets that would allow oil to drip out at this location.
Roy :

that can smell bad

Customer: At least none that haven't been replaced.
Roy :

could be axle seal or or axle boot torn also grease on exhaust

Roy :

does not take much to make smell on exhaust

Customer: Except I can see it dripping from the bell housing. I'll just have to have them put it on the lift and verify their work and if it's not the seal to show me where it is.
Roy :

that would be you best thing to do

Customer: Again thanks. Hopefully they get it figured out. They stated one day for repair and had it for two. Afraid to see what happens next.
Roy :

Ok your welcome and good luck ,Thank you ROY!

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