Just been reading through the 'tech' forum, and came across this thread.

https://www.cherokeeforum.com/f2/200...estions-45786/

States that drive line vibs can occur in the front drive shaft due to a high lift.

I have an RC 6.5 lift coming, and only have a Dana30 (low Pinion) fitted.

Am I expected to get drive line vibs in the front, and do I have to fit a HP Dana30,???? Never heard this before - Only issues with the rear Driveshafts etc....

Cheers for any response.......

 

Its possible. Are you going to get an SYE? A t-case drop will work as a band-aid. I have a RC 4.5" lift with a t-case drop and mine doesnt vibrate at all.

 

Its less common to get front drive line vibes, but it could happen! Your kit should be coming with the Tcase drop & that should be enough for the front, but you for sure wanna get a slip yoke for the rear shaft!

 

was just gonna say, an SYE will not help the front driveshaft, only the back. But for a transfer case drop, at least on mine, it seems to point the output for the front shafter at a higher angle. I'd say the best way to go about fixing it if you have that problem is an SYE instead of the drop so the transfer case isn't tilted back, and swap out that low pinion Dana 30 for a high pinion Dana 30. But you won't know for sure if you're gonna get vibes until you have the lift installed.

 

It is possible on low pinion front ends. You will have two choices. Adjust the castor angle and straighten out the angle on the pinion u joint, or swap to a high pinion front end. Another option is to put a CV joint on the other end of the drive line too.

 

I've got the SYE and driveshaft sorted for the rear end, for when the kit arrives... so after your recomendations, I will fit the kit - see what vibrates - then look for a HP Dana30 if required.

Cheers for the help !!

 

Most vibes tend to come from fronts with auto lockers. The front driveshaft doesn't always turn with an open front but when it is locked it turns all the time. If the angles aren't perfect or the shaft isn't balanced you will get some vibration. That being said the difference in a low and high pinion front is only a few inches and if you have bad vibes the high pinion won't completely get rid of it. I ran 7.5" on my HP front with a locker and got lucky. Only vibes I had were from my tires because they were never balanced.

 

I'll see what vibes I get when I install the lift,.. incidently, I had fitted 33"TSL Swampers fitted to my last 4WD, and had an absolute nightmare trying to get them balanced properly. Has put me off getting Swampers in the future. Mite try 33" Silverstones (Simex copies) this time round.

I hope that once the kit is installed, caster angle set correctly, all will be well. - no vibes

 

Usually the front drive line vibrations occour when you have an excessive wear of the splines. Also vibrations are generated by rotational torque (like in the back) but in normal conditions the front DS is just dragged by the front wheels and no force is applied in 2wd.

 

If you have front driveline vibes a TC drop will make them worse. A TC is for rear DS vibes ONLY, it can and will make front pinion angles worse and cause vibes. Good reason for the SYE and DS for the rear. You can't do a SYE in the front, as it already, is set-up that way. You can adjust your control arms to adjust the pinion angles. If you get front vibe causes are Pinion angle, worn splines, ujoints, pinion bearing, damaged DS.