Gas_Guzzler4800
3rd May 2012, 08:02 AM
Hey guys I have been chasing a thud from the rear of my 2002 GU 4.8 manual. It is quite intermittent and happens under varying conditions. Sometimes its while releasing the clutch from a standstill, sometimes its after the clutch pedal has been fully released and the truck has been rolling for a metre or two etc. I slid under and noticed my upper trailing arm bushes were absolutely flogged out so I had these replaced ( with rubber ) and it has helped but not fully cured the problem. The lower bushes appear to be in good condition with no excessive movement or visible cracks etc. I thought it may be related to the backlash in the diff as I notice the car jerks/lunges when the accelerator is released and reapplied at speed. However, there is very little play at all, well within tolerance.
Im thinking I may have to remove the lower trailing arms and inspect the bushes off the car to be sure and I'll check the rear calipers arent sticking while I am there. Has anyone else come across this issue or the jerking/lunging at speed?
Also this problem seems to happen immediately after fitting a 3" lift kit, which also got me thinking. The spline on the rear tailshaft may have been worn in a certain spot. Lifting the car will effectively move the position of the spline further out. Maybe when the rear end drops on take off it slips back into the worn spot on the spline?
Im thinking I may have to remove the lower trailing arms and inspect the bushes off the car to be sure and I'll check the rear calipers arent sticking while I am there. Has anyone else come across this issue or the jerking/lunging at speed?
Also this problem seems to happen immediately after fitting a 3" lift kit, which also got me thinking. The spline on the rear tailshaft may have been worn in a certain spot. Lifting the car will effectively move the position of the spline further out. Maybe when the rear end drops on take off it slips back into the worn spot on the spline?