TheSloMoShow
NAXJA Forum User
- Location
- Columbus,OH
Hi everyone.
I've recently been running into a pretty irritating issue on my XJ that won't go away. I'm hoping someone has some insight on which direction I should pursue next.
<Symptoms>
1. "tick" at idle
2. hard tapping/vibration under load (1500-2500 rpms), every gear except OD.
<Assumptions>
1. Bad flexplate
2. Exhaust leak (manifold/gasket/flange gasket etc)
3. I'm paranoid and just need to let this go.
<Findings>
I bought this Jeep in Nov/2015, and never noticed this noise/vibration until after I installed my SYE this past March. Almost instantly, I noticed that while under load (1500-2500 rpms) and in every gear but OD, there was this really apparent tap/vibration from right beneath my feet. As soon as I let off the gas though or as soon as it kicks into the next higher gear the vibration subsides a little. Then, completely subsides once in OD.
My initial thought was incorrect driveline angles with the install of the SYE, but the rear pinion yoke is correctly aligned with the TC side yoke. Just a week ago, I happened to come across a thread about loose flexplate bolts and cracks.
So, I pulled the cover this last weekend. All bolts were tight and I didn't notice any cracks. I actually pulled the bolts out, and re-tightened with loctite to spec. I did notice though, the holes in the flexplate that the 4 bolts go through are somewhat 'ovaled'. I didn't know if this is how OEM flexplate comes, or if those 4 holes should be as tight as the o.d. of either one of the 4 bolts. There was a slight bit of play in the flexplate (fore and aft) if I pryed at the flexplate teeth with a wrench (maybe 5-10mm of play). Also, I let the Jeep run with the cover off and there's no visible wobble - it seems centered.
I do notice that the tapping sound goes away a bit after warmed up or a long drive, although the vibration/tapping feeling never subsides. It only goes away when engine load goes back to 0 or once finally in OD.
<Question to the Forum>
So my question is, what do you feel is the next best step?
I originally was deadset on replacing flexplate and torque converter, but now am having doubts. I don't mind the work to do this job, but only if I know it's going to fix the issue. Seeing as this sound has sometimes just been an exhaust leak for others, I'm not sure replacing flexplate will do anything (although the fact that I have a vibration in my floorboard leads me to believe it is the plate).
...How would you determine if the culprit is an exhaust leak? I don't know of any "smoking gun" ways besides finding visually some crack etc.
...Can the flexplate still be bad, even if no visible signs of cracks or warpage?
...if I happen to pull the transmission, what other items besides torque converter, flexplate, trans oil pump and rear main seal are worth inspecting and/or replacing?
Maybe both issues are there and I need to fix each, but I can't stand to spend money and time fixing something only to find you fixed it for no apparent reason :banghead:
Thanks for the help!
I've recently been running into a pretty irritating issue on my XJ that won't go away. I'm hoping someone has some insight on which direction I should pursue next.
<Symptoms>
1. "tick" at idle
2. hard tapping/vibration under load (1500-2500 rpms), every gear except OD.
<Assumptions>
1. Bad flexplate
2. Exhaust leak (manifold/gasket/flange gasket etc)
3. I'm paranoid and just need to let this go.
<Findings>
I bought this Jeep in Nov/2015, and never noticed this noise/vibration until after I installed my SYE this past March. Almost instantly, I noticed that while under load (1500-2500 rpms) and in every gear but OD, there was this really apparent tap/vibration from right beneath my feet. As soon as I let off the gas though or as soon as it kicks into the next higher gear the vibration subsides a little. Then, completely subsides once in OD.
My initial thought was incorrect driveline angles with the install of the SYE, but the rear pinion yoke is correctly aligned with the TC side yoke. Just a week ago, I happened to come across a thread about loose flexplate bolts and cracks.
So, I pulled the cover this last weekend. All bolts were tight and I didn't notice any cracks. I actually pulled the bolts out, and re-tightened with loctite to spec. I did notice though, the holes in the flexplate that the 4 bolts go through are somewhat 'ovaled'. I didn't know if this is how OEM flexplate comes, or if those 4 holes should be as tight as the o.d. of either one of the 4 bolts. There was a slight bit of play in the flexplate (fore and aft) if I pryed at the flexplate teeth with a wrench (maybe 5-10mm of play). Also, I let the Jeep run with the cover off and there's no visible wobble - it seems centered.
I do notice that the tapping sound goes away a bit after warmed up or a long drive, although the vibration/tapping feeling never subsides. It only goes away when engine load goes back to 0 or once finally in OD.
<Question to the Forum>
So my question is, what do you feel is the next best step?
I originally was deadset on replacing flexplate and torque converter, but now am having doubts. I don't mind the work to do this job, but only if I know it's going to fix the issue. Seeing as this sound has sometimes just been an exhaust leak for others, I'm not sure replacing flexplate will do anything (although the fact that I have a vibration in my floorboard leads me to believe it is the plate).
...How would you determine if the culprit is an exhaust leak? I don't know of any "smoking gun" ways besides finding visually some crack etc.
...Can the flexplate still be bad, even if no visible signs of cracks or warpage?
...if I happen to pull the transmission, what other items besides torque converter, flexplate, trans oil pump and rear main seal are worth inspecting and/or replacing?
Maybe both issues are there and I need to fix each, but I can't stand to spend money and time fixing something only to find you fixed it for no apparent reason :banghead:
Thanks for the help!