Clunking sound when decelerating

[lefty7]

Just replaced the rear tires and now have a clunking sound when decelerating. It sounds like I'm going over cracks in the road. I seen some other posts that for auto/full time 4x4 you need to change all four tires at the same time is this true? Is there anything else it could be?

 

[Radeon]

From what ive read.Change all four tires or tires must be within 2/32 of each other.

 

[lefty7]

Yeah I've seen the same thing but just want to be sure before I go out and buy two more tires.

Thanks

 

[kworonowski]

yea i found out that even if you are within the 2/32 you may still run into the problem of the tires overall circumfrence being off (different years have different sidewall heights) even with the same make n model. best to go with matched set. best of luck'

 

[Exproblems]

I seen some other posts that for auto/full time 4x4 you need to change all four tires at the same time is this true? Is there anything else it could be?

>>>>>>>>>>>>>>>>>>>>>

Nope, you got it. Just like the others are telling you. All 4 tires should get replaced at the same time and be of the same size and dimensions, tread depth etc. From what I read in here, you can pull the fuse to the auto 4x4 to keep the system from trying to engage due to the unbalanced size in tires until you can get another 2 new tires to match the others you just bought. Personally, I hate the auto 4x4 system. I liked it better when you ran in 2 wheel drive full time and selected 4 wheel drive when needed. This system just causes more headaches and is more costly when it comes to tires. Kind of explains why Ford keeps advertising tire sales on TV and claims to sell more than 3 million tires per year and uses Tv show "Dirty Jobs" host Mike Rowe as their pitch man.

 

[lefty7]

Thanks for the info, It turns out it's not as critical as you might think. Did some research and found that the tires should be within 3/4 inch circumference. like I said I bought two new tires for the back and had the noise, I then checked everything underneath fluids, uv joints etc and found nothing wrong. I then pull the 4x4 auto fuse and the problem still existed but not as bad. Then I measured the circumference of each tire, my front tires are 1 1/2 inches smaller. I then put my spare on the passenger front, my spare is about the same size as the new back tires and the problem went away. So this tells me that with the spare on the front there is less binding. So yes it's the tires. lol

Thanks for your help.
Lefty7