Not sure if it is a problem...

[Esther]

1986 fj60, stock everything, 117000 miles. I have this weird noise from my tranny, it seems to come and go at no particular time and sounds like a revving motor, but quieter. On any given trip, it will make the noise for about 5 seconds or less, off and on during the trip. There is no loss of power and rpm gauge is fine. Someone suggested that I check the fluids, I did. The T-case fluid is clean and good, the tranny fluid is a bit dirty, but not ready to change just yet, maybe in 1000 miles. By the looks of the clean T-case fluid, I would suspect the the seals between the two are fine. I still am trying to determine if this noise I hear is something bad or something normal. I put 5000 miles on the truck since I bought it and it has always made the noise. BYW, new T-fluid 5000 miles ago.
I searched the posts but can't find anything. What do you transmission folks know about this?
John
PS: I searched.

 

[2mbb]

Could it be your radiator fan clutch? This kicks in and out depending upon temperature under the hood. It does sound like a revving motor. However, it comes from the front of the engine, not the transmission. Have you listened with the window open and closed to see if you can pinpoint where the sound is coming from?

 

[Trapper50cal]

Thats....

Could it be your radiator fan clutch? This kicks in and out depending upon temperature under the hood. It does sound like a revving motor. However, it comes from the front of the engine, not the transmission. Have you listened with the window open and closed to see if you can pinpoint where the sound is coming from?

That's what my first thought was....also Sometimes the pressure plate will scrape slightly when not in gear and and clutch is disengaged.

 

[Esther]

I'll check the fan thing with windows up and down. Never thought of that.
The pressure plate thing? How do you check that? I am not sure if this is related, but the last time I had it in four, it popped out and I had to hold it back in over a really rough road. It never did this before, I just thought it was a fluke because the truck was really bouncing. Is this related to the noise I hear?
John

 

[Trapper50cal]

Well

I'll check the fan thing with windows up and down. Never thought of that.
The pressure plate thing? How do you check that? I am not sure if this is related, but the last time I had it in four, it popped out and I had to hold it back in over a really rough road. It never did this before, I just thought it was a fluke because the truck was really bouncing. Is this related to the noise I hear?
John

You start the engine, engage the parking brake, take the truck out of gear and engage and disengage the clutch, listen for a difference in the noise that correlates to the clutch going in and out.

That being said, I thin the noise is the clutchfan, and it is normal. It is not however related to the disengaging transfercase. IDK on that one....