1998 5.0L V8 Explorer BW 4404 TC

[jjvanderlaan]

I've been having an issue with my 1998 Explorer, it's an AWD V8 5L. As I accelerate it has been making a knocking/banging sound somewhere in the driveline. As I accelerate it knocks hard several times, and then starts to go away as I gain speed. I have inspected all the usual suspects: driveshaft CV joint, CV axles, u-joints, etc. and all seem to be in good shape. The only thing I did notice was that the spline on the end of the front driveshaft was a bit loose, but not to the point where it would be skipping teeth.

I suspect the issue may be in the transfer case based on some reading I have done. I am thinking loose chain in the transfer case or viscous coupling?

With the front drive shaft removed, the sound goes away. Currently I have both drive shafts removed and the case seems to have more slop than it should. See the videos below. I am not familiar with transfer cases so I am unsure if there should be this much play? Would this be a loose chain or viscous coupling issue based on what I am describing?





Thanks
Jon

 

[410Fortune]

I would suspect the CV connection on your front d shaft, the t case side of things. Even though it looks okay these joints are the weak link in the front driveline and can cause a ratcheting noise like you describe.

You can however drain the fluid from the AWD t case and have a look at it. These AWD t cases do wear out, usually we see 160-180K miles from them, with regular fluid changes you can see well over 250K miles

Your t case does seem to be making a noise in that video, although it is hard to see what you are doing. With both d shafts un hooked there will be some slop back and forth.

How many miles on your 98?
Have you checked the boots on your CV axles?
Any excessive play in the front differential?
How are your wheel bearings?

 

[jjvanderlaan]

I drained the fluid last night and it was brown and muddy looking.

In the video I am simply moving the output flange on the front side back and forth.

The Tcase was put on roughly 40K miles ago and was a used one, I have not changed the fluid since. I don't recall how many miles were on the Tcase at the time, but the truck itself has 240K.

The CV axle boots looked to be in good shape and the front diff seemed solid. Wheel bearings should be good, they were done roughly 2 months ago.
If the CV axles were bad, would I be able to pull them off and tell?

Thanks for the input.