I know 4.5 is what most say. but others say 6.5? others 8? i have a pre 97 with t-case drop. think i can manage 6.5 for a bit before i get the sye?

 

Well if you can manage it than whats the question?

Personally I wouldn't go above 4.5.

 

The question is not how high CAN you go, the question is how high SHOULD you go if you don't want to screw up other stuff.

The way I look at it, if you're looking to drop the coin for a 6+" jack on the truck, doing it right is not that much more expensive.

 

mine has 8.5" and no SYE....

There's no problem if your rear transmission has a good angle

I feel a little vibration when it reach 100 KPH ...

 

I've an 01 with 5 1/2" of lift with a TC drop....no vibration or noise at any speed ...maybe I just got lucky

 

Main factor is what transmission and rear axle you have

Ex. A d35/ax15 jeep will be able to go higher without an sye than an aw4/8.25 jeep will

With that being said, if your rear has good droop then id suggest it sooner

 

I wouldn't go above 4.5" without it. Even if you don't have vibes, the angle still isn't good for your transfer case.