Viper6791
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- #1
Hi everyone, my first post officially but have been reading the forum since I got my JL 2 years ago. So, I have 37s and a 2.5 inch lift. It’s a sport but I have rubicon axles regeared to 4.88. Recently in 4 hi I’ve had weird vibrations above about 40 mph and it gets more intense as I go faster. This is on snow covered roads by the way so not a driving on paved roads in 4 hi issue. Also present on paved roads to test though. My first thought is of course my front drive shaft. As you know the JL has a FAD so it makes sense it’s only there in 4 hi. The part that throws me is it miraculously disappears once u pass about 55-60. Does the FAD kick in at this speed? When I shift into 4 hi above around those speed, which I know you aren’t supposed to I was just testing it, it vibrates for about a half a second and then stops, seemingly going back into 2hi even though the t case shifter is still in 4 hi position. So my two questions are: is my hunch that it is the front drive shaft vibrating correct? And why does it seem to disappear suddenly above a certain speed? Thanks, Zach.
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