yet another mystery sound? help

[hokie8358]

ok i know one more mystery sound to solve!! but i need major help on this one,so put your thinking caps on. i purchased a m1008 from the DLA in richmond va. bout 10 months ago. you guys on here got me through the death wobble issue,which was a first. thanks!! just last week i installed a 6in. all leaf skyjacker suspension lift, with 315 size mastercraft mud tires. now keep in mind before stock i had no issues or sounds with it at any speed.

now when i accelerate 0-25mph still good but when i hit 40-55 cruisin speed and you maintain or let off on the fuel, there is a loud clanging or metallic grinding or rubbing sound coming from the cab to the rear diff. area. now ,when i give it power again it quits and is smooth. and when you really notice it is when you take it out of gear and throw it to neutral say at 40-50mph rolling along with 6.2 idling at that speed IT SOUNDS AWFUL!!

now the only things thus far i have done to it to rule out sum things is,replaced the bent driveshaft of course and joints was good top and bottom when installed,new rear wheel cylinders and the brakes were good and spindle bearings inner and outer was fine. so i say i am at a stand still!!

please help. oh yeah almost forgot, when truck is setting still i put it to neutral on level ground with engine off and moved the rear driveshaft, is it normal for it to rotate half way around and then to return back to original spot? i am assuming this is the locker unit allowing it to do this. all info is greatly appreciated. thanks

 

[Barrman]

You are able to rotate the input yoke on the rear axle more than 180° with the truck in neutral and the parking brake on, correct? I just tried that on a CUCV 14 bolt across my class. Maybe 30° of free play. I think you need rear differential work.

 

[hokie8358]

yes, i can grab the rear driveshaft and rotate it 180 degrees in neutral. when i let go it returns back to the starting posistion.

 

[chevyCUCV]

My driveshaft does not spin back like you are saying, with rear wheels off the ground what happens?

I would guess your rear end is messed up?
Have you pulled the rear diff cover yet?

 

[transman]

I would bet on rear diff issues. pull the cover and check the condition and quanity of lube (or lack of).With the driveshaft held from moving the ring gear should only move about .010 .(the thicknessof a match pack). Too much play or gouges/scratches on thegear teeth are signs of trouble. checking this way takes the locker out of the equation.

 

[hokie8358]

what happens when tires are off the ground, i spin one wheel and the other
moves in the same direction. i will pull cover in a bit and check the unit. i have not done this but you can tell that sum one has been in it before.

 

[SGT Estum]

When jacked up, if you spin one rear wheel the other should be turning in the opposite direction.

 

[Barrman]

Not with a locker in the rear. Or at least, not with a locker that is still there and working.

 

[SGT Estum]

Not with a locker in the rear. Or at least, not with a locker that is still there and working.

Good point... for whatever reason I was thinking M1009. I should read more carefully

 

[Ghost2012]

Good point... for whatever reason I was thinking M1009. I should read more carefully

Try going past 180... could it be a tire SO out of round it's weighted to one side?