Smoking in 4WD

Tiny
TODD NICKOLES
  • MEMBER
  • 2008 FORD F-150
  • 5.4L
  • V8
  • 4WD
  • AUTOMATIC
  • 180,000 MILES
I was driving my truck on icy road in 4wd high for approximately 10 miles or so. I starting noticing a burnt oil smell. Then I noticed smoking and front end got kind of tight feeling in my steering wheel. I pulled off of the road. I raised the hood and could see smoke coming from around exhaust at the bottom of the engine.
Wednesday, February 17th, 2021 AT 4:33 PM

8 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,755 POSTS
Hi,

Were you able to tell if it was engine oil or something coming from the driveline? For example, was the leak coming from the transfer case, transmission, front differential?

Let me know. Also, if you did see the oil, what color was the fluid?

Let me know.

Take care and God Bless,

Joe
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Monday, April 12th, 2021 AT 12:00 PM
Tiny
TODD NICKOLES
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Thanks for responding Joe. I checked engine oil and transmission fluid it all looked good and at full levels. I did not look under truck because of ice and snow on the ground. Hope this was helpful.
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Monday, April 12th, 2021 AT 12:01 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,755 POSTS
Hi,

Since it does it in 4wd, I have a feeling it is coming from the transfer case. I attached a pic below and circled where the front driveshaft attaches to the transfer case.

If you can, check there for dampness.

Let me know.

Joe
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Monday, April 12th, 2021 AT 12:01 PM
Tiny
TODD NICKOLES
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I crawled under the truck this morning and looked at where shaft connects and didn't see any dampness, actually no dampness anywhere around the transmission or transfer case. Really stumped?
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Monday, April 12th, 2021 AT 12:01 PM
Tiny
TODD NICKOLES
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I can still smell the burnt oil really strong.
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Monday, April 12th, 2021 AT 12:01 PM
Tiny
STEVE W.
  • MECHANIC
  • 13,476 POSTS
Check the power steering fluid, if the steering got tight it could be a bad pressure line to the steering and only leaking when under higher pressure. If it has low fluid then start hunting.
It could spray onto the exhaust and then the leak "vanishes" because of the way it is leaking. Have seen a tiny pinhole in a line do that more than once. Didn't find the leak until I had someone hold the steering wheel hard to the lock to force the pump into the relief valve, then there was a steady stream, but the hose would close back up under normal pressure and no drips or even much of a stain.
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Monday, April 12th, 2021 AT 12:01 PM
Tiny
TODD NICKOLES
  • MEMBER
  • 5 POSTS
Reservoir is full. Have been using Lucas stop leak for a while. How would I know if it is front differential? Remember it happened only in 4 wheel drive. And very strong burnt gear oil smell.
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Monday, April 12th, 2021 AT 12:01 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Hi,

if it smelled like gear oil, then it would have come from the differential. If I recall, the transfer case has ATF in it. The front differential takes 80w90 gear oil.

Here is a link showing how to check it:

https://www.2carpros.com/articles/differential-gear-oil-fluid-check

Let me know.

Joe
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Monday, April 12th, 2021 AT 12:01 PM

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