Noise/Vibration on acceleration

[Dave Savard]

Hi, its been a while since I posted here, but I have a strange low frequency noise, almost more like a vibration, when accelerating from a dead stop. It is worse when accelerating and turning to either direction, seems to be coming from the rear of the truck. It lasts for only several seconds, then is gone. Slowing down to a stop, even while turning, does not produce the same effect.



'04 ST 58K miles, 4.10LS, 1.5" TT, Warrior Shackles, 265-75-16 Toyo Open Country ATs, Rancho RSXs, PCM not flashed for tire size, rear wheel well liners trimmed- no rubbing there, tires rotated - no change, tire pressure 36psi front and rear.



Any ideas?



Dave S.

 

[Todd Z]

Dave try it in 4wd... Maybe it is a rear axle brg, Rear brg



But it sounds like the slip that is felt when the rear clutch packs go bad.



Check your gear box fluids, and maybe change the rear fluid or add and extra friction modifier bottle to the rear.... and do some slow figure 8's in a parking lot to lubricate the clutches properly...





Todd Z

 

[Dave Savard]

Thanks Todd,

Fluid levels are all OK.

You're thinking along the same lines I am. I was considering ordering a Trickflow or Summit rear cover and swapping to RP in the diff this weekend, if it warms up. Cheap and fast, and if it doesn't cure it, I guess I can try to talk SWMBO into a Detroit, ARB or Eaton locker!



Dave S.

 

[Todd Z]

I would diagnose it first before you spend all the money on oil and covers....



Todd Z

 

[Dave Savard]

Thanks Todd,

I'm going change the lube and add FM to it anyway, I consider it part diagnosis, part PM. The cover is something I was planning on doing at some time in the future as well, if only for looks. $40.00 for fluids is just piece of mind, even if it doesn't solve the issue and gets thrown away having to go back in again. Pulling the cover is better than just sucking out the old fluid, I can check for and clean out any metal and friction plate material at the bottom that could cause more damage if left there unseen.



Same in 4wd, tried it while at lunch. Jacked up each end of the axle and got no play in the wheels, either in/out, up/down, or side/side too. No excessive heat build up that would go with a toasted bearing. Seems solid there, I had inspected under the disks inside the e-brake area for any leakage at 55K when I did the last rotate. Problem existed then and I was wondering if anything was loose inside and dragging.



Thanks again,

Dave S.

 

[Gavin Allan]

Bad rear U-joint.