let's talk rear d/shaft vibes...

it doesnt look like i'll be getting the SYE done this week.... with the impending road trip to Moab i honestly dont know how worrried i should be about the increased vibes from the rear shaft... this is reffering to my 99 XJ by the way... i get it at about 30 mph mildly, then again from about 64 to 73 mph.... not too bad if i can keep it above or below that range.. Moab means 5000 miles in 11 days!! from what i know the vibes are from the ujoint angles being out of plane and the fact that the later t/cases have a longer unsupported output shaft... i assume uncorrected vibes will lead to ujoint failure and t/case and pinion bearing stress.... i dont expect anyone to tell me how long i can run without a problem but at least tell me what kind of vibes you are living with and for how long maybe.... we all know how to get rid of them, but how bad are vibes really?? i may get the new shaft and take it with me to Moab just in case..
mike

The fact that they are there should worry you.. the fact that you know they are at one speed but not really as much at another should also worry you... you can damage bearing, seals and cause whole sorts of problems...... I know that somehow I messed up the rear seal on the tranny when I was playing with vibes, angles, SYE...... (over the period of couple months or so) and as a result I was leaking much of that expensive GL3.....

i'm torn here.... guess i have to put off some stuff and just plain DO IT!!!!

You may also want to consider springing for a HD SYE kit.The hacn-n-tap kit didnt do it for me so I changed it out for a JB Kit(No vibes now)!Way stronger and about 4" more drivshaft length(less angle).

Just for a completely different outlook on the issues. driveline vibes vary from very mild (some people do not notice) to almost not drivable. Simple fact, the stronger the vibes the more damage they will do. living with bearable vibes in small amounts for a period of time may reduce the life of the joints and or maybe even a seal but it is near impossible to try to predict what it might or might not do (particularly with such a long drive).

You might also want to consider changing the angles in order to affect/move the vibrations to less significant places (over 75mph) for example.

My basic thought is that if it is bearable to drive with the vibe it probably will not do too much damage as long as you do not leave it for too long of a period of time (but the chance is always there).

Michael