GrazniM
10-18-2007, 04:08 PM
So I purchased Ford's 4.10 Racing performance ring and pinion set and 8.8 differential cover an install kit, 75w-140 fluid, friction modifier, etc. Went to my mechanic and spent the day with his crew during the install. All appeared to go well but the test drive at the end of the job did not....
Seems that at 18mph+ there is a regular clunking that can be heard and felt during coasting or deceleration; it is more pronounced between 20 - 30mph and the regular clunking slows as the vehicle loses speed.
Of course it was back on the lift: a second set of checks were made - and the axels and carrier were pulled again and backlash reset. All back in, another road-test.... same issue.
Initial backlash was just under .012 (the max), on the second attempt this was readjusted to about .007 (under the min of .008). We had also verified good tooth contact with marking compound. The second time around we also tested on the lift (car in drive) accelerating to 10 - 15 mph results in nothing, 20+ mph - regular clunking until the speed falls below 18mph.
No marks on new ford cover (though it feels like something is hitting something internally - hard to tell as the vibration travels). Not to influence opinion, but the carrier looked like it had very very light abrasions on one side (diagonals maybe about an inch in length) that might have come from the front end of the pinion???
Any thoughts/help would be appreciated; the guys at the shop are thinking a bad ring and pinion set (they encountered another bad set on a Ford truck the previous week). I'm keeping the car on ice until I can work this one out.:(
Seems that at 18mph+ there is a regular clunking that can be heard and felt during coasting or deceleration; it is more pronounced between 20 - 30mph and the regular clunking slows as the vehicle loses speed.
Of course it was back on the lift: a second set of checks were made - and the axels and carrier were pulled again and backlash reset. All back in, another road-test.... same issue.
Initial backlash was just under .012 (the max), on the second attempt this was readjusted to about .007 (under the min of .008). We had also verified good tooth contact with marking compound. The second time around we also tested on the lift (car in drive) accelerating to 10 - 15 mph results in nothing, 20+ mph - regular clunking until the speed falls below 18mph.
No marks on new ford cover (though it feels like something is hitting something internally - hard to tell as the vibration travels). Not to influence opinion, but the carrier looked like it had very very light abrasions on one side (diagonals maybe about an inch in length) that might have come from the front end of the pinion???
Any thoughts/help would be appreciated; the guys at the shop are thinking a bad ring and pinion set (they encountered another bad set on a Ford truck the previous week). I'm keeping the car on ice until I can work this one out.:(