drive train deamon i cant chase down
 

hello im new here and have a problem i cant find that i have researched to death!
my 2008 ranger 4x4 posi rear end with 260km on it has a weird thumping in the drive train, when cold it dosent do it , its only after driving for about 20 mins it starts and keeps getting worse till i park it for a few hours.
its hard to tell where its coming from , id have to say rear, it dosent seem to change under acceleration or decel,its not effected by turning...seems the worst at 30mph but is still there thru out any speed and its like a thump at every rotation of the driveline,and sometimes feels also like the thump is a loose metalic noise if that makes sense...
this winter i inspected rear end and axle bearings replaced one axle bearing, rear end looked to be fine with no wear on ring or pinion, pinion has no play that i can find
i replaced rear drive shaft u joints, one u join has a little side to side play between the caps now but other than that is tight up and down
im driving it with no front drive shaft right now, no difference
ive had this problem for almost a year but in the last few months it had got progressively worse to the point where i wont drive long distances with it,
i put a used auto trans in it in the fall with no change to my drive line problem

anyone have any ideas??? i cant figure out why it starts after 20 mins of driving? its so bad that i would think it would be there even when cold...

Have you rotated the tires, bad tire can do that.

If it is an extended cab the carrier bearing could be the problem but usually a different symptom.

The limited slip axles require a friction modifier to allow "slipping", this is an additive or you can get oil with it already added.

yup i have friction mod in it, its not like shuttering cluthes.

mine is extended cab but it has one solid steel drive shaft, i kinda thought all the newer ones had aluminum shafts in them but mine was steel since i bought it... and it has the blue grease on the slip joint...i think thats the proper stuff ford recomends?
i havent rotated tires but i have put a different set on since ive had this problem i should try that just to rule it out...

You said one of the U-joints has a little side play between the caps. That is not normal. There should be no play or movement in the U-joints in any way. I think you have a defective U-joint.

Drive train
 

I would take drive shaft out and have it balanced, the slip yokes are junk on these trucks from the factory

i was thinking i should do that, theres no weights on myne but its also so rusty i cant see where there would have been some tacked on , but i would think if its out of ballance it would also do the same thing cold, im taking out the rear drive shaft now and putting my old tires on to see if it makes a change.... hate to take my shiny explorer rims off tho, they look good on a ranger

I would try balancing the driveshaft yourself first, just to see if that might be the problem.

Google: balance drive shaft with clamps

Not expensive or even hard to do, if it improves balance, less vibration, then it would be worthwhile getting it professionally done.

Yes, the u-joints shouldn't have any play, and would be tight when cold and then loosen up as grease warmed up.
So really worth a second look at that

Hi all, first posty here. agree with u-joint replacement. I just checked mine hoping I would find one with play, but not the case. What I did find was a lot of play in / at the rear end. Anyone have experience with this?

Welcome to the forum.

You should start your own thread, what you are doing is called "high jacking a thread" since you are asking a question about your own vehicle in someone else's thread.

But not to worry, just start one of your own by clicking on New Thread button on forums main page.

Also as far as the question...........is the play on the pinion so in and out movement of drive line, or is the play rotational, i.e. you can turn the driveshaft 1/4 turn or 1/8 turn before it stops?

If your shocks have over 80k on them, I would look at them. On the ranger, when they get weak (and you do not notice it that much because of the stiff suspension) they cause your tread to wear a little funny.
I just experienced it with mine, and I thought I had drive parts going bad or even a bearing.
Put new shocks on, and they keep better contact with the road. If your tires are not worn too bad the new shocks will help even the wear back out after a while and the noise will go away.
Also experienced it on my old 2002 Ranger.

Thank you guys for the helpfull info
i replaced both u joints in my rear shaft, and i have got one vibration taking care of, the slight thump i felt every rotation is now gone, but i am still experiencing a rumbeling vibration as the drive train heats up,almost feels like gears are not messing properly and randomly something is trying to bind up, does not feel like a rear end, so im leaning more towards the transfercase, i also hear a high pitched bearing noise the more i drive it...

can anyone explain what a streched chain in the t case will feel like?