Hello. I have a problem with my 2000 Expedition. I had a flat rear tire and changed it with the spare. The actual size of the tire was 315/70/17 and the spare 265/70/17. When I drove it with the spare to the tire shop to get it fixed, my suv started to squeal from the rear end and making clunking noises and I was only driving it at 25. After leaving the tire shop I noticed the clunking more when I make a turn like the u joints were out but I just replaced them 7 months ago. Any ideas on what it could be?

 

Sounds like the tires gave the posi a hard time. Only chatters in turns and 2000 has a straight axle, right? I'd have the rear fluid changed and add new posi additive. Could be some particles in there and that is probably the least expensive thing you can do. Plus, it can't hurt... it can only help, even if it's not the problem.

 

Did you have it in A4WD when you had the spare on it? If so the problem you experienced was probably the speed sensors seeing the wheels spinning at different speeds and trying to engage the 4wd. Why it continued after the original tire was put back could point to something being torn up.

 

@ developer yea its a straaight axle.
@ alwaysfords41 no the 4wd was off it was on awd also if it was the speed sensors what can i do to fix this?

 

You have A4WD as one of the positions on your 4 position dial (not AWD), which is what I was after. You weren't in 2WD is the key. The speed sensors saw the different rotational speeds of the wheels as wheel slippage and were causing the truck to go into 4WD to correct it. The speed sensors aren't what is shredded, it is likely something in your 4WD drive line.

 

Ok thanks but one thing I checked is that when I put it in 4hi it drives great no struggling but when I don't have it on 4hi it struggles a bit Could It Be That the shift motor might be stuck??

 

If it were stuck it would act the same in both positions. You put the original tire back on after it was fixed, correct?

 

Pull the fuse for the 4WD system and see if the noise goes away.

 

some lube place put non posi fluid in my 99 expy posi rear diff and that screwed it up...was skipping let to right and making a lot of noise...