1999 explorer knocking/ clunking on full throttle

[frankie15oct]

Hey everyone! Been a while since I have been on here. Hope someone can help! I have a 1999 ford explorer with 4.0 and AWD. I have a clunking or knocking noise that appears to be coming from the back seat area when I accelerate at WOT . The sound comes at WOT and then seems to go away if I keep my foot in the throttle. I am hoping it is either a u joint or possibly the slip yoke in the two piece rear drive shaft. Anyone help or familiarity with this problem would be greatly appreciated!

 

[drdoom]

How many miles on that piece, and have you had any problems with the transfer case?

 

[frankie15oct]

I have about 155,000 miles on it. Transfer case seems to operate ok, what little I have tested it. Unfortunately I am a new owner to it. When I checked the play from transfer to rear drive shaft I found some movement but not sure how much should be too much. Thanks for replying!

 

[pbnj22]

the 4.0 with AWD... is that prototype!?

 

[drdoom]

Some rotational play is normal. The u joints, slip yoke, and companion flanges should be tight.

 

[frankie15oct]

All U joints and flanges feel tight, will 're check up down and side to side play and report back. I may be referring to the transfer case incorrectly. The shift switch is labled AWD 4H and 4 low with AWD being the normal setting. I don't think that with it being a 1999 that it would be a prototype? Thanks for all the help and replies

 

[frankie15oct]

Ok checked all all areas for play and did I not feel and excess. Checked at transfer case and rear diff and no play found. Thanks again

 

[frankie15oct]

To anyone who replied or followed this posts... My problem was as simple as rear tires had lower tread depth than front. Had the auto 4x4 going nuts I guess? new tires, problem fixed. Go figure..

 

[bluestream1]

SO you have a 5.0 not a 4.0???

 

[frankie15oct]

No 4.0 .