Ford Fest Posted March 20, 2014 Report Share Posted March 20, 2014 (edited) I'm asking because I said I would. . . I've had my 40th for a couple of years now and it has always made a howling noise when I reach 60 mph+. It only happens with acceleration, sound goes away when you lift off of the gas, doesn't matter what gear. It seems that it occurs when the pinion angle is changed at that speed. Meaning, as I'm driving at 60 mph and it is howling, if I go over a bump or dip in the road it wil stop for a brief second. Based on other threads and talking to a few TS members it sounds like it is the ring/pinion. They say this typically happens if the gear wasn't set-up correctly or if it was a bad set of gears when it has been swapped, most common to 3:73. According to SAI, they did not swap ring/pinion during conversion. My Ford tech says it does not appear thet the cover has ever been off of the housing. However, I rotated the drive shaft and the driverside rear wheel turned 3-3/4 turns and I turn around 2,000 rpm (maybe it's 2,200) in 6th gear going 65 mph. I have the same wheel/tire package from conversion. I contacted Ford Racing to order a new ring/pinion and described the issues. They said to hold off and ask other 40th owners if they have the same issue before we go to ripping in to the differential. They thought it could be the Eibach suspension package, hard bushings, a bearing or the 2 piece drive shaft (mentioned there is a bearing in it). The stock LCA, UCA and mount are still on the car. I have not greased the suspension and not sure it has been done since conversion back in 2009 and 4,000 miles later. Only been in the rain once, never through a car wash etc. if that matters. I did purchase grease, just waiting on the salt and sand to diisappear. Do any of you have this same issue? What rpm are you runting at 65 mph in 6th? Assuming you still have the same set-up Thoughts? Edited March 21, 2014 by Ford Fest Quote Link to comment Share on other sites More sharing options...
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