Drivetrain BANG noise

[Scannerboy1968]

I have a 98 Explorer Limited. It has 180,000 miles and I recently experienced a front hub bearing go bad (thought I was going to loose the wheel from the terrible sounds it made). Anyway got that problem fixed and drove it for about 3 weeks before the next problem started.
Upon quick acceleration off of the line, there is a very load deep bang in the drivetrain (almost like a U-joint breaking). After you get up to speed, everything is fine. Also if you take off gradually up to like 20 or 25 and then accellerate, everything is fine. Being a full time AWD, my theory is it might be a duel ratio transfer case and the lower ratio is having a problem. What are your thoughts on problems ?

Thanks, Andy

 

[maxcr3]

I had the same noise on my 99 explorer 161,000 miles. I spent a lot of time and money tracking it. I would start with changing the transfer case oil. The clutches could be the problem. After drive shafts, spider gears, axles, changing the transfer case fluid fixed the problem. I heard the noise decrease with the fluid change. By four weeks the noise was completing gone. I used Amsoil oil.

 

[Scannerboy1968]

Fluid Change?

Max,
That is one item I have extremely neglected on this vehicle. I have never changed fluid and I have owned it since 50K miles. But from a couple postings I have read, there is some kind of viscous coupling inside it? I appreciate the recommendation and will definately give it a shot. What is the spec required for the Amsoil?
Thanks, Andy

 

[maxcr3]

Andy,
I used Amsoil Synthetic Universal Automatic Transmission Fluid 2.7 Pints. It was a snap to change.
Max

 

[Scannerboy1968]

Thanks for Fluid Spec

Max,
Again, I appreciate the response and fluid spec. I'll give it a shot.
Thanks, Andy