I've had some trouble with vibrations since I did a front axle swap. I immediately concluded that it was my front drive shaft but the actual problem eluded me for a long time, until 10 mins ago while I was working under my jeep. My front DS is too short, it seems.

According to this site my collapsed length should be 28.620". First of all, what exactly does the collapsed length refer to? Is it from cap to cap when it's fully collapsed? On my rig, sitting on level ground and normal ride height, I measured roughly 33.5" from cap to cap (which is the problem.) I'm going to replace my current DS with one out of a ZJ, but I don't know which. The previous link has a measurement table for all ZJs but I'm not sure which one would be appropriate. Should I go for the 33.5", the 33", the 32.875", etc?

 

since you are lifted you should measure the distance from tc yoke to axle yoke, whatever that length is ideally you want a ds that fits that when the ds is in the center of its travel. give or take a 1/2 " . since you usually need more travel for drop than compression, more travel out is better than in. can you dig it.

 

Mostly for my own reference, what axle did you have and what was it replaced with?

 

Yea, I measured the 33.5" from cap to cap while the driveshaft was still connected (albeit barely). So you suggest I go for the 33" one?


It's the same model axle, D30. I went from stock 99 HP D30 to a 97 HP D30 that I built. But for some reason, it's given me lota of problems that I can't explain. It was the same model and same lift so why did I have to get longer shocks? Idk.

 

96/98 5.2, 5.9 31.250 w/ 249 & Model 30 52098379


96/97 4.0 Automatic 31.250 52098850

Measurements are center to center on u joint .....

 

There is a D30 that has a shorter pinion. Perhaps you have one..
Longer shocks? Did the other axle have Bar Pin Eliminators?
Control Arm Drop systems push the axle forward also.

 

is that 33" THE CENTER OF THE SLIPS TRAVEL ? IF SO YOU COULD USE IT. if that 33" is fully compressed it too long, if fully extended its too short.

 

I've not heard of any HP D30 models having a short pinion, but if that's true, I think you might be right. Old axle didn't have BPEs, but I added them to the new axle because why the hell not! CAD brackets do push the axle forward, but I had the same brackets and control arms on the old axle as well.

Thanks for all of the response guys, I think I going to go with the 33" one when I get a chance. I've got to finish my high steer and sort out problems with my track bar first though.

 

Thanks for all of the response guys, I think I going to go with the 33" one when I get a chance. I've got to finish my high steer and sort out problems with my track bar first though.


Gonna be to long will bottom out on compression....