- Joined
- Mar 20, 2005
- Location
- Hendersonville, NC
Fighting driveline vibes on my wife's ZJ. Here's the deets, as the youngins say...
1998 ZJ, 3.5" lift on 32s. The ZJ had vibes when I first installed the lift years ago, but only 70 and above. Since we never drive it that fast, we didn't do anything about it. Earlier this year, I installed 4.56 gears to aid with performance and transmission longevity. After installing them, the same vibes were present, but now at 53 to 60.
It has the 242 transfer case and it is a very light wheeler. So I decided on the Hack n tap SYE from Iron Rock Offroad.
The above is the style of SYE installed. I then installed a 1310 series double cardan shaft from @Oliver's because Dave builds awesome shafts and I run them in everything. His are all I install in my shop also.
Took it out for a test drive. Vibes are present from 40-50, but acceptable. However, from 50-55, they are very noticeable. From 55-61, it's like driving on rumble strips. Very unpleasant and unacceptable. Once you pass 61, they immediately dissapate and once again are acceptable. Our commute is about 18 miles on 55 MPH roads, so obvuously I need to fix this. Dave sent me a repalcement shaft, just in case, with no change.
Stats:
Driveshaft angle is 11.5*. Measured with angle meter on shaft.
Pinion angle has been set from 8*-12*. Measured on back of housing on machined flat surface where you would install a housing spreader for diff work.
No vibes with rear shaft removed.
All of the adjustments yielded no real change. Over 12* you start getting noise along with the vibes. This is obviously wrong, but I did so just to see what would happen.
The SYE flange is flat against the output shaft, dampened with RTV so no metal to metal contact. The splines are not bottomed out on the flange. 2" present on output shaft and 2.5" present on the flange.
The axle is centered left to right via the track bar bracket. No compound agles present.
On jack stands, the vibe and noise comes in just like on the road, no change.
The vibe is felt in the rear of the Jeep and can be felt in the chassis. Without a doubt it is coming from the rear. You can feel it in your butt while driving. It feels like incorrect driveline angle or a poorly balanced shaft. But the angles are correct and I trust Dave's work.
Looking for off the wall ideas here. I have installed literally hundreds of SYE/driveshaft combos over the years and never had an issue like this. I have never installed one of the IRO hack n tap kits, before but it is admittedly just cut off x" of shaft, drill, tap, install.
Ideas, suggestions and smart @$$ remarks will be equally appreciated.
1998 ZJ, 3.5" lift on 32s. The ZJ had vibes when I first installed the lift years ago, but only 70 and above. Since we never drive it that fast, we didn't do anything about it. Earlier this year, I installed 4.56 gears to aid with performance and transmission longevity. After installing them, the same vibes were present, but now at 53 to 60.
It has the 242 transfer case and it is a very light wheeler. So I decided on the Hack n tap SYE from Iron Rock Offroad.
The above is the style of SYE installed. I then installed a 1310 series double cardan shaft from @Oliver's because Dave builds awesome shafts and I run them in everything. His are all I install in my shop also.
Took it out for a test drive. Vibes are present from 40-50, but acceptable. However, from 50-55, they are very noticeable. From 55-61, it's like driving on rumble strips. Very unpleasant and unacceptable. Once you pass 61, they immediately dissapate and once again are acceptable. Our commute is about 18 miles on 55 MPH roads, so obvuously I need to fix this. Dave sent me a repalcement shaft, just in case, with no change.
Stats:
Driveshaft angle is 11.5*. Measured with angle meter on shaft.
Pinion angle has been set from 8*-12*. Measured on back of housing on machined flat surface where you would install a housing spreader for diff work.
No vibes with rear shaft removed.
All of the adjustments yielded no real change. Over 12* you start getting noise along with the vibes. This is obviously wrong, but I did so just to see what would happen.
The SYE flange is flat against the output shaft, dampened with RTV so no metal to metal contact. The splines are not bottomed out on the flange. 2" present on output shaft and 2.5" present on the flange.
The axle is centered left to right via the track bar bracket. No compound agles present.
On jack stands, the vibe and noise comes in just like on the road, no change.
The vibe is felt in the rear of the Jeep and can be felt in the chassis. Without a doubt it is coming from the rear. You can feel it in your butt while driving. It feels like incorrect driveline angle or a poorly balanced shaft. But the angles are correct and I trust Dave's work.
Looking for off the wall ideas here. I have installed literally hundreds of SYE/driveshaft combos over the years and never had an issue like this. I have never installed one of the IRO hack n tap kits, before but it is admittedly just cut off x" of shaft, drill, tap, install.
Ideas, suggestions and smart @$$ remarks will be equally appreciated.
Last edited:
